Topic 5.1 conception
?有氧呼吸和无氧呼吸
有氧呼吸
?见书
无氧呼吸
?见书
无氧呼吸在植物体内的表现
?1由植物的基因型决定
?a水稻种子发芽时, 有氧 =无氧
?b好气型种子
?小麦 玉米 向日葵在发芽初期也进行无氧
呼吸
?c 一些体积大的生活组织 （ 甜菜块根和马
铃薯块茎 ）
?如肉质浆果 → 苹果 （ 内部常进行无氧呼
吸 ） 内部黑斑的产生
?伤害 能量浪费
?d 水稻等植物是有强烈的无氧呼吸系统
?2 环境因素
呼吸代谢的生理意义
?A供能
?B 供原料
?C加强植物的抗病能力
?例：将有毒物质较为无毒物质, 使伤口
迅速木质化
Topic 5.2 植物呼吸代谢的多
样性
topic 5.2.1 高等植物呼吸代谢的多条
路线的概念
?
? 1965年 汤佩松
?全能自主多样性高等植物其呼吸代谢途径不可
能只有一条固定不变途径进行, 必然是在时间,
空间上的不同搭配 （ 程度, 速度 ）
?多条途径并非在某一植物同时存在, 即使同时
存在也非同时启动
?植物采取哪条路线, 主要取决于内因与外因 。
?内因 （ 不同植物器官, 组织, 发育年龄 基因型 ）
?外因 —环境中的温度 水 O2 CO2 病害
topic 5.2.2 呼吸途径的多样性
一、糖酵解 EMP
?一, 糖酵解 EMP 最终产物：丙酮酸 氨
基酸 乙醇 乳酸
?关健酶；磷酸果糖激酶 丙酮酸激酶
?O2是重要的调解因子
?抑制剂：碘乙酸 氟化物 竞争性地结合 3-
磷酸甘细醛脱氢酶的巯基
二、三羧酸循环
?1953
?见书
三、磷酸戊糖途径（ PPP or
HMP）
?如何检测葡糖分子的氧化通过以上三种
途径中的一种？
?用 14C—1和 14C—6标记的糖 分别供给两
个相似的植物组织, 测定各自释放的
CO2
?若是经过 EMP—TCA C6/C1=1
?若经过 PPP则在一般时间内 C6/C1＜ 1
?高等植物中多数组织的 C6/C1=0.50.—
0.75
PPP的生理意义
?① 能量：控制能量
?② 与物质中间代谢联系
?③ 是细胞内 NADPH重要源泉
四、乙醛酸循环途径
油料植物种子萌发时, 脂肪酸 → 糖
五、二羧酸循环（ DCA）
?普遍有在于微生物植物中有, 较少在低
等植物是 TCA的补充途径
六、光呼吸途径（乙醇酸代谢途径）
topic 5.2.3 电子传递链的多样性
?呼吸链
?氧化磷酸化
topic 5.2.4末端氧化酶的多样性
1．细胞色素氧化酶
?主要的末端氧化酶与多条链相联系, 占整个化
酶的 50%
?普遍存在于各种组织, 幼嫩组织中最活跃,
?正常情况下植物的主要末端氧化酶, 与 O2亲和
力很高
?低 O2情况下保证呼吸代谢正常退化
?耗 O2里的 3/4由此 E承担
2 抗氰氧化酶（交替氧化酶）
?对氰化物不敏感, 氧化磷酸化作用相对
较低, 称为产热或放热呼吸, 形成 ATP
少, 能量主要以热量散失 。
?广泛存在于高等植物和微生物, 还有玉
米, 豌豆, 绿豆的种子, 马铃薯的块茎,
胡萝卜的块根
?主要存在于, 天南星科海芋属 睡莲 等
沼泽植物
海芋属
?佛焰长序, 早春开花, 为了保证传粉,
这种产热呼吸保证植物在早春温度较低
时完成发育, 同时放热使恶臭散发, 吸
引苍蝇, 帮助传粉
?见 Essay 11.3
作用
?（ 1） 可达 1000—15000微升 /O2/鲜量 /小时
?可使温度上开至 40℃
?（ 2） 促使种子萌发
?（ 3） 分流电子的作用, 降低 满溢效应
?满溢效应 在细胞主路电子处于饱和状态
时, 细胞色素主路电子传途径发生满溢,
TCA循环较迅速时, 抗氰呼吸相对开高 。
3 多酚氧化酶
?荔枝的储藏：必须抑制酶活
?芒果的储藏
?樱桃, 水蜜桃：
?（ 1） 采取早, 中, 晚育种的樱桃, 分期
上市
?（ 2） 加工成缸头
?烟草：金黄色：迅速脱水, 抑制多酚氧
化酶的活性
?黑褐色
?在果品的保鲜, 缸头, 加工中多涉及此
酶的活性
4 抗坏血酸氧化酶
在胚胎发育中, 酶活
?在果蔬加工中, 抑制此酶活
5 黄素氧化酶
?见书
?注意电子传递链和末端氧化酶的多样性
?见书
电子传递链图解
酶 金属辅
基
辅酶 定位 与 o2亲和
力
与 ATP偶
联
细胞色素氧化酶 血红素
Fe
NAD 线粒体 极高 +++
交替氧化酶 非血红
素 Fe
NAD 高 +
酚氧化酶 Cu NADP 细胞质 中 —
抗坏血酸氧化酶 Cu NAD 低 —
乙醇酸氧化酶 NAD 乙醇酸
氧化体
低 —
几种末端氧化酶主要特性比较
?In addition to the five standard
protein complexes found in nearly all
other mitochondria,the electron
transport chain of plant mitochondria
contains five additional enzymes
marked in green,
?None of these additional enzymes
pump protons,
?Specific inhibitors,rotenone鱼藤酮
for complex I,antimycin for complex
III,cyanide氰化物 for complex IV,and
salicylhydroxamic acid (SHAM) for
the alternative oxidase,are important
tools to investigate the electron
transport chain of plant mitochondria,
Topic 5.3
The Alternative Oxidase
?The presence of the alternative
oxidase (AOX) is one of the features
that sets plant (and fungal)
mitochondria apart from mammalian
mitochondria.
?This enzyme has therefore received a
lot of attention from plant scientists
? we now have a fairly good
understanding of the regulation of its
activity
?quantifying the AOX activity
? the role of the AOX in whole plant
respiration
The Structure
? The alternative oxidase is a quinol对苯二酚
-oxygen oxidoreductase and it does not
pump protons,
? The oxygenase transfers electrons from
ubiquinone泛醌，辅酶 Q to oxygen and
generates water as the end product of the
reaction so four electrons must be
transferred to oxygen,
?The precise mechanism for this is
not known,but the protein has iron
binding motifs,so the oxidation
reaction probably requires Fe
?The functional form of the enzyme is
a dimer,with the two polypeptides
either covalently or non-covalently
bound to each other,
?predicted structure places the
protein in the inner mitochondrial
membrane,with the active site and
the regulatory cysteines exposed to
the matrix,
The Amount and Activity of the AOX
Are Carefully Regulated
? The AOX does not pump protons,so when
electrons from NADH oxidation flow
through the AOX,at least two of the three
sites of proton translocation are bypassed,
Therefore,energy conservation in the
form of ATP is much smaller when the
OAX is active,
? The activity of the AOX must therefore be
carefully regulated,
?There are several AOX isoforms in
some plant species,The relative
amounts of three isoforms of AOX
vary with age in soybean cotyledons
子叶,the best-studied developmental
system,
The total AOX amount increases with
age,as does the capacity of the AOX
pathway
Treatment of cell cultures with
antimycin A,which inhibits complex
III,or with H2O2,which causes
oxidative stress both induce AOX
expression
?The activity of AOX is also stimulated by
2-oxo含氧的 organic acids,in particular
by pyruvate丙酮酸,
?This may be a feed-forward mechanism
that upregulates the capacity of the
electron transport chain when the
glycolytic end product is available,（ 即
防止满溢效应）
AOX Activity Can Be Measured In Vivo
?For many years,benzhydroxamic
acid derivatives,(e.g.,
salicylhydroxamic acid (SHAM),were
used to quantify the capacity and
activity of the AOX pathway in both
isolated mitochondria and intact
tissues.
AOX capacity
?AOX capacity was determined from
the rate of respiration in the
presence of KCN,which blocks the
cytochrome pathway,and corrected
for residual respiration in the
presence of both KCN and SHAM.
AOX activity
?AOX activity was determined from
the decrease in the rate of respiration
when SHAM was added in the
absence of KCN,
?The assumption was that the
cytochrome pathway was always
activated first and that the AOX would
be engaged only when the cytochrome
pathway was saturated
?However,as we have seen above,this
assumption is not correct,
?A better method for measuring AOX
activity is now available,It makes use of
the fact that cytochrome c oxidase and
AOX do not discriminate against 18O
relative to 16O to the same extent.
?The so-called oxygen discrimination of
the sample (tissue or mitochondria) can
be measured by mass spectrometry
? (1) with KCN to resolve the oxygen
discrimination by AOX
? (2) with SHAM to resolve the oxygen
discrimination by cytochrome c oxidase
? (3) without inhibitors to resolve the
discrimination value resulting from the
activity of the both enzymes,
?From these values the percentage
contribution by AOX and cytochrome c
oxidase to the total uninhibited rate of
respiration can be calculated.,
The Alternative Oxidase has Several
Functions
Function 1
The AOX pathway appears particularly
active in thermogenic产热的 flowers and
it is primarily responsible for heat
production
?Respiration through the cytochrome c
oxidase system cannot generate an
appreciable increase in tissue
temperature,
Function 2
?The alternative oxidase may also work as
a bypass to oxidize NADH and FADH2
under ADP-limiting conditions under which
the cytochrome oxidase pathway is
restricted,
?In this way,the citric acid cycle and the
glycolytic pathway can continue to run and
provide the cell with biosynthetic
precursors,
Function 3
?The AOX pathway also limits the
formation of reactive oxygen species
(ROS),ROS are formed as byproducts
of electron transport under aerobic
conditions
?ROS can cause damage to proteins,
lipids,and DNA and the cell must
therefore limit their formation,
?AOX helps prevent overreduction of the
electron transport chain and thus
lowers ROS production
?Maxwell demonstrated the importance
of the AOX for limiting ROS formation
in living cells,
?They measured the ROS level in a wild-
type tobacco cell culture and in cells in
which the amount of AOX was either
overexpressed or reduced by
antisensing,
?Overexpression of AOX lowered the
steady state level of ROS,whereas
underexpression caused a five-fold
increase in cellular ROS,
?This result also points to the
mitochondrion as an important site of
ROS generation in plant cells.
Topic 5.4 Temperature Regulation by
Thermogenic Flowers
?These groups are all primitive原始 seed-
plants with large,fleshy肉质的 floral
structures that are often associated with
beetle,bee or fly pollinators,
?Heat production is usually thought to
enhance the production and dispersal of
floral scents气味 that make the plants
more attractive
?or be a reward to insects by keeping them
warm in floral chambers where they
remain overnight,
Example
?Some species,such as the arum海芋属
lilies百合,are so intensely thermogenic
产热 that their flowers can increase up to
35° C above the surroundings,
?in Brazil,the inflorescence of
Philodendron selloum is capable of
warming to over 40° C at air
temperatures close to freezing.
?Skunk cabbage,Symplocarpus foetidus
can maintain temperatures above 15° C
when the air temperature drops to –
15° C,and it often melts the snow
around the plant
Substrate
? the substrate for respiration is
starch,often imported from other
parts of the plant,but in P,selloum,
the substrate is lipid that is stored
in the florets prior to blooming,
?Analysis of heat production by direct
calorimetry and respirometry show that
all of the energy in the substrates ends
up as heat.
?Although there is the possibility of some
energy going into phosphorylation of
ADP or into synthesis of floral
structures,this appears to be negligible,
Respiratory rates
?The respiratory rates of some
thermogenic flowers are the highest
among plants,and in fact exceed even
those of warm-blooded animals.
? For example,the tissue of Arum maculatum
produces up to 0.40 Watts per gram (W g–1),
while a flying hummingbird produces only
0.24 W g–1,
? At an air temperature of 10° C,a 125 g
inflorescence of P,selloum produces about
five times the amount of the heat of a 125 g rat
under the same conditions,
? Such high rates of heat production demand a
good supply of oxygen.
Supply of oxygen
? In the florets of P,selloum,this is achieved by
diffusion through a network of tiny
intercellular gas spaces that permeate the
tissue to the center.
? The demand for oxygen is so high,that the
oxygen partial pressure at the center of the
floret drops to about one-quarter of
atmospheric,but remains just above the
critical level where oxygen uptake becomes
diffusion-limited,
?A few species of the most powerfully
thermogenic flowers also exhibit
temperature regulation,that is,they
regulate the rate of respiration and
achieve a relatively constant
temperature in the flower,regardless of
external air temperature
?In these cases,the respiratory rate
increases almost linearly as the ambient
环境 temperature drops,and the mean
temperature of the flower is almost
constant
Physiological
thermoregulatory温度调节
control mechanism
? The physiological thermoregulatory control
mechanism is not known
? It is certain,however,that it is unlike the
mechanism in birds and mammals that relies
on a complex nervous interaction between
temperature receptors,central nervous
system processing,and control of organs that
affect rates of heat production and loss.
? In plants,the regulation must occur at a
strictly biochemical level,
?One possible regulator is salicylic acid水
杨酸,which is known to be involved in
triggering thermogenesis in arum lilies,
?Another possibility is the AOX
The reason of
Temperature regulation
? In animals,its adaptive value is to maintain
high and stable body temperatures that
permit them to be active under cold
conditions,
? Compared to thermally compliant
poikilotherms (cold-blooded animals),animal
homeotherms are able to find more food,
compete better for territory and mates,and
reproduce faster—all evolutionarily
advantageous in many circumstances
?Temperature regulation is not a
requirement to enhance the
vaporization of scents; unregulated high
temperatures would suffice满足
?there is increasing evidence that
thermoregulation in flowers is a service
offered as a reward to insect visitors,
?Large flying insects,chiefly beetles,
which require high body temperatures
during activity,often pollinate first,
thermoregulatory flowers
?Second,these insects often remain in
floral chambers for about a day,and
thermoregulation coincides with this
period,
?During their residence,they mate,eat,
and digest—activities that benefit from
high temperatures,
?If beetles inside P,selloum had to
produce their own heat actively to raise
body temperatures to 35° C,they would
use about 50 times the amount of
energy as they would during passive
heating inside a thermogenic flower.
?While many non-thermoregulatory
flowers offer energy in the form of
nectar,starch,or pollen to their insect
visitors,thermoregulatory flowers can
offer energy directly as heat,
? studies of the dragon lily Dracunculus
vulgaris show conclusively that
thermoregulation is not associated with
scent production,but more likely with
beetle entrapment
? The 80 cm inflorescence of this arum lily
consists of a floral chamber and a large spike
钉,called the appendix,protruding above it,
? During the first day of blooming,the
appendix produces a powerful scent of rotting
meat that attracts carrion beetles吃腐肉的甲
虫,which fall into the chamber and provide
pollen to receptive female florets小花,
? They remain in the chamber overnight while
the female florets become nonreceptive,and
they are released the next day after being
showered with pollen from the male florets,It
is significant that the appendix is strongly
thermogenic,but not thermoregulatory,Its
heat is entirely lost by evaporation of water
carrying the scent,and respiration falls with
decreasing ambient temperature,
?On the other hand,respiration in the
floral chamber rises with decreasing
ambient temperature,the characteristic
of thermoregulatory tissue,
?Because the site of thermoregulation is
associated with the site of trapped
beetles rather than the scent production,
it is consistent with the idea of an
energy reward,
Topic 5.5 FoF1-ATPases,The World's
Smallest Rotary Motors
?FoF1-ATP synthases (also called F-
ATPases) are present in the inner
membranes of mitochondria,
chloroplasts,and bacteria,
?these large,multisubunit enzymes
consist of a water-soluble catalytic
complex (F1) attached to an integral
membrane protein complex (Fo) that
transports protons across the
membrane
?The F1 complex is composed of at
least five different types of subunits
(three α,three β,one γ,one δ,and
one ε),When the F1 complex is
dissociated from the membrane,it is
active as an ATPase,
?In fact,under the appropriate
conditions the intact FoF1-ATP
synthase can run in reverse and act
as a proton pump,using the energy
of ATP hydrolysis to move H+ across
the membrane
Binding-change
mechanism
?1,The major energy-requiring
step is not the synthesis of
ATP from ADP and Pi,but the
release of ATP from the
enzyme,
?2,Substrate is bound and
products are released at three
separate but interacting
catalytic sites,corresponding
to the three catalytic subunits
(β subunits),Each catalytic
site can exist in one of three
conformations,tight,loose,or
open,
?3,The binding changes are coupled
to proton transport by rotation of the
γ subunit,That is,the flow of protons
down their electrochemical gradient
through the Fo complex causes the γ
subunit to rotate.
?The first two predictions of the
binding-change model are supported
by many lines of evidence,mainly
kinetic studies,and are now
generally accepted,
?However,the prediction of a
rotary mechanism for coupling
proton flow to ATP synthesis has
been more difficult to
demonstrate,Recently,two major
breakthroughs have led to
confirmation of the third
prediction as well.
The first breakthrough
?the determination of the crystal
structure of the F1-part of bovine
mitochondrial ATPase by the
laboratory of John Walker in
Cambridge,England
?The crystal structure showed that the
three catalytic β subunits differ in
their conformations and in the
nucleotide bound to them,consistent
with the binding-change mechanism,
?the γ subunit is inserted like a shaft
轴 through the center of the catalytic
complex,which consists of three α
subunits and three β subunits
arranged alternately in a
doughnutlike炸油圈饼 似的 structure,
? Moreover,the interface between the γ
subunit and the α and β subunits is highly
hydrophobic不亲水的,
? The hydrophobicity of the interface
minimizes the interactions between the
subunits,consistent with the rotation of
the γ subunit within the hole formed by
the catalytic complex,
?In other words,the γ subunit looks like a
molecular bearing轴承 lubricated by a
hydrophobic interface,
The second discovery
?Definitive demonstration of rotation
requires a video recording of the
spinning of the enzyme in real time,
?But although they are large for
proteins,F1-ATP synthases are still
far too small to be visualized in a
light microscope.
? To visualize the rotation of the enzyme,
Masasuke Yoshida and his colleagues at
the Tokyo Institute of Technology came up
with an ingenious精巧 method to make the
enzyme much larger than it is,
? they attached an actin filament labeled
with a fluorescent dye to the base of the γ
subunit using another protein as a "glue."
? They then attached the F1 complex upside
down to a glass surface,
?If the γ subunit rotates with respect to the
catalytic complex,the actin filament
should swing around with it,
? Since the filament is very long compared
to the ATP synthase (about 1 μm),its
rotation should be visible in a
fluorescence microscope.
?In other words,the fluorescently
tagged actin filament,which is large
enough to visualize in a light
microscope,reports the rotation of
the γ subunit
?The results were spectacular!
? When ATP was added to the
modified enzyme,the actin filaments
were seen to swing around in a circle
at as much as 4 revolutions per
second in a fluorescence microscope
?To give some idea of scale,if you
were a γ subunit,this rotation rate
would be equivalent to swinging a
several hundred meter-long rod
around your head at 4 revolutions
per second in water
?However,the measured velocity is
undoubtedly an underestimation of
the actual velocity in vivo,because
of the enormous torque扭矩 required
to swing such a large mass,
? For their contributions to elucidation of
the mechanism of ATP synthesis,Paul
Boyer and John Walker shared half the
Nobel prize in physiology or medicine in
1997,
? The other half went to Jens Skou for his
pioneering work on the K+,Na+-ATP
synthase,the mammalian counterpart of
the plant plasma membrane H+-ATP
synthase
The binding-change mechanism
A method for visualizing rotation of the γ subunit
Sequential images of the rotating actin filament attached
to the γ subunit
as viewed in a fluorescence microscope,
Topic 5.3影响呼吸作用的因素
?呼吸速率和呼吸商
?氧气
?二氧化碳
?水
?温度
第五章复习题
?名称解释：
?呼吸链 呼吸系数 呼吸控制比 抗氰呼吸
末端氧化酶
?1,有氧和无氧呼吸各有何特点
?2,比较光合作用与呼吸作用
?3,植物呼吸代谢多样性的基本内容？ 有
何生理意义？
?4,如何判断呼吸底物是经 EMP-TCA或
PPP途径降解？ 细胞内糖降解首先进入
哪种途径是受什么因素调节？
?5,HMP途径有何生理意义？
果蔬储藏时呼吸作用的二重性
?呼吸作用是一切生命活动的重要标志,
果蔬在储藏过程中的一切生理变化, 都
靠呼吸作用来维持 。 它们离开了栽培条
件, 不能进行光合作用, 无法制造养分 。
呼吸所产生的能量, 一部分用来维持自
身的生命活动, 使之保持自身对外界微
生物的侵入具有抵抗能力, 也使自身对
表皮伤口有一定的愈合能力；另外, 一
部分以热能的形式释放, 即呼吸热 。
?呼吸作用既是本身生存的表现，又是自
身消亡的动力。
?储藏的 目的：尽量延长前者的时间，阻
止后者的出现。
苹果贮藏
?苹果是我国市场上主要果品之一，也是
各地果品贮藏的重要种类苹果的品种很
多，供市场的主要品种就有了 30多个，
按成熟期分为早熟、中熟、晚熟三类，
?早熟品种在 6月下旬至 7月下旬成熟, 有
祝光, 伏花皮, 黄魁 。 由于生长期短,
果肉组织不够紧密, 因而不耐储藏, 一
般不作为储藏品种来用 。
?中熟品种主要有红玉, 元帅 （ 红香蕉 ） 金
冠 （ 黄元帅, 金帅 ）, 红星, 秋花皮等,
在八九月间成熟, 风味较好, 较耐贮藏 。
随着冷库的建设, 这类苹果的贮藏日益增
多
?晚熟品种主要有国光, 鸡冠, 青香蕉, 印
度青红 。 在 10月至 11月上旬成熟, 质量一
般较好, 耐贮藏, 是贮藏的主要品种 。
一、对贮藏条件的要求
?贮藏苹果的适宜温度为 0— 1℃, 适宜空
气相对湿度为 85— 90%,适宜气体成分
为：氧浓度 2-4%,二氧化碳为 3-5%。
?因黄元帅等中熟苹果在采摘时正值秋老
虎季节，气温果温都较高
?据试验，苹果在 4.4℃ 下成熟速度比在
0℃ 条件下快一倍 ;在 9℃ 下比要 4.4℃ 快
一倍；在 21℃ 下又比 9℃ 下快一倍也就是
说，苹果采摘后在室外 21℃ 放一天，就
等于缩短了 7-10天的冷藏寿命。
?因此, 采后及时预冷降温, 尽快散掉果
实所带的田间热, 降低果实内的呼吸强
度, 对保证后期质量, 延长贮藏寿命具
有非常重要的作用 。
?预贮 对果, 蔬贮藏都有重要 。
?红香蕉苹果在贮藏中容易出现“返砂”现象，
除与品种特性有关外，与采后的延时预冷降温
关系重大
?所谓“返砂”是指果皮开裂果肉外露，口感绵
软的现象，主要是因为果实中的原果胶分解为
水溶性果胶，与纤维素分离，使细胞间的结合
松弛，果实于是由硬变软，失去清脆的风味
?如果采摘后及时预冷降温，降低其呼吸强度，
则可以减缓“返砂”的发生。
二、贮藏方法
?1 适时采收
?采收标准
?以红香蕉苹果为例
?可溶形固形物 10% 以上, 果实硬度
16.5%磅 /平方米, 着色面积 95%,用淀
粉染色时, 果心线内的部分不在被染色 。
从时间上算, 一般为果树盛长后的 147天
左右 。
?2,准备好包装材料
?a.塑料 （ 无毒聚乙烯 ） 袋
?不是聚氯乙烯
?b,硅胶窗
?硅胶窗
?用一种透气性极强的薄膜塑料一硅橡胶,
做成气体交换窗 （ 硅窗 ） 镶嵌在普通的
包装薄膜帐 （ 袋, 或库, 窖的气窗上 ）
即可以自动调节贮藏环境中 O2和 CO2浓
度, 这种气调方式称为硅窗气调
?CO2与 O2的透气比为 5,1。这种透气比
对贮藏水果、蔬菜很适合，只要在包装
塑料上镶嵌一定面积的硅橡胶，加上适
宜低温，即可达到保护目的。
?用硅窗气调贮藏果蔬能省去人工调节 O2
和 CO2浓度的工作, 能够节省 N2和有关
设备, 具有方便可靠投资少特点 。
?3．贮藏前药剂处理
?① 苹果采收后, 用 6%的 Cacl2浸果, 可
提高果实硬度, 降低生理病害发病率,
好果率比对照提高 7-8%。
?② 溴氯烷薰蒸
?溴氯烷是一种薰蒸型广谱抗药剂, 有较好的杀
菌和抑菌作用, 对青霉菌等有很好的杀伤效果 。
?从苹果品种来看, 对抗菌能力差的苹果, 薰蒸
效果越明显, 如果在薰蒸后对果实进行包装,
以采用纸包装的效果好 。 这是因为与塑料包装
相比, 还有透气性好, 降温快等优点 。
?使用时, 每百斤果实用 20克溴氯烷, 防病效果
好
?4,贮藏方法
?（ 1） 硅窗气调法
?用塑料薄膜制成塑料帐，装上硅窗，框
架放在塑料底垫上，苹果放在框架中，
每层边高可达 1.2米，可放多层，罩上塑
料帐，大帐垂边与底边叠几圈、压紧、
造成贮存苹果的密封环境
?苹果装在帐内，由于苹果呼吸，帐内氧
气逐渐减少，二氧化碳浓度高于大气，
这样就形成两种气体与大气的正负压差，
帐内 CO2由硅窗排出,O2从大气中透入，
当氧气含量低于 2%时，可打开气调帐的
气体平衡孔，放进少量空气，补充氧气。
?硅窗气调法贮藏苹果, 贮存的时间广,
损耗较小, 不耗能量, 不需大设备, 适
合于广大农村采用 。
?2,纸箱贮藏
?每个苹果用白纸包好,0 ℃ -2℃ 贮藏，
检查 除腐烂果
其他章节的知识点
光敏色素
?红外光和远红外光都可影响植物光形态
建成, 其受体是光敏色素, 一种可溶于
水的色素蛋白, 它广泛存在于除真菌以
外的低等和高等植物中, 对光周期, 花
诱导等都有重要影响 。 光形态建成指依
赖于光的控制细胞分化, 形态结构以及
器官与组织的建成 。
组织培养
?指在无菌条件下，分离并在培养基中培
养离体植物组织的技术。
?愈伤组织,一团无分化状态的细胞
?分化与脱分化
植物激素的种类及功能
生长素, 3 -吲哚乙酸 （ IAA）, 萘乙酸
（ NAA）, 2,4-二氯氧乙酸 （ 2,4-D）
?赤霉素, GA
?赤霉素和生长素的作用
?细胞分裂素, 6-苄基嘌呤 （ 6-BA）, 激
动素 （ KN）, 玉米素 （ zeatin）
?细胞分裂素与生长素的比值
?脱落酸 （ ABA）
?乙烯,成熟激素
? 乙烯利
春化作用
?低温对植物开花或促进开花作用
呼吸骤变,
?当果实成熟到一定程度时, 呼吸速率首
先是降低, 然后突然增高, 最后又下降,
此时果实进入完全成熟 。 这个呼吸高峰,
称为呼吸骤变 respiratory climacteric）
即果实的后熟
? 具有呼吸骤变的果实有：苹果, 香蕉,
梨, 桃
? 不具有呼吸骤变的果实有：橙, 凤梨等
基因芯片：
?又叫 DNA微陈列, 是指固定在固相载体
上的高密度 DNA微点列, 具体地说就是
把大量靶基因或寡核苷酸片段有序地,
高密度地排列在玻璃, 硅等载体上, 称
之为基因芯片 。
?基因芯片的应用，给生命科学的研究带
来了革命的推动，它具有高通量、大规
模、高度并行性、快速高效、高灵敏度、
蕴藏高价值以及高度、自动化等诸多优
点。
?有氧呼吸和无氧呼吸
有氧呼吸
?见书
无氧呼吸
?见书
无氧呼吸在植物体内的表现
?1由植物的基因型决定
?a水稻种子发芽时, 有氧 =无氧
?b好气型种子
?小麦 玉米 向日葵在发芽初期也进行无氧
呼吸
?c 一些体积大的生活组织 （ 甜菜块根和马
铃薯块茎 ）
?如肉质浆果 → 苹果 （ 内部常进行无氧呼
吸 ） 内部黑斑的产生
?伤害 能量浪费
?d 水稻等植物是有强烈的无氧呼吸系统
?2 环境因素
呼吸代谢的生理意义
?A供能
?B 供原料
?C加强植物的抗病能力
?例：将有毒物质较为无毒物质, 使伤口
迅速木质化
Topic 5.2 植物呼吸代谢的多
样性
topic 5.2.1 高等植物呼吸代谢的多条
路线的概念
?
? 1965年 汤佩松
?全能自主多样性高等植物其呼吸代谢途径不可
能只有一条固定不变途径进行, 必然是在时间,
空间上的不同搭配 （ 程度, 速度 ）
?多条途径并非在某一植物同时存在, 即使同时
存在也非同时启动
?植物采取哪条路线, 主要取决于内因与外因 。
?内因 （ 不同植物器官, 组织, 发育年龄 基因型 ）
?外因 —环境中的温度 水 O2 CO2 病害
topic 5.2.2 呼吸途径的多样性
一、糖酵解 EMP
?一, 糖酵解 EMP 最终产物：丙酮酸 氨
基酸 乙醇 乳酸
?关健酶；磷酸果糖激酶 丙酮酸激酶
?O2是重要的调解因子
?抑制剂：碘乙酸 氟化物 竞争性地结合 3-
磷酸甘细醛脱氢酶的巯基
二、三羧酸循环
?1953
?见书
三、磷酸戊糖途径（ PPP or
HMP）
?如何检测葡糖分子的氧化通过以上三种
途径中的一种？
?用 14C—1和 14C—6标记的糖 分别供给两
个相似的植物组织, 测定各自释放的
CO2
?若是经过 EMP—TCA C6/C1=1
?若经过 PPP则在一般时间内 C6/C1＜ 1
?高等植物中多数组织的 C6/C1=0.50.—
0.75
PPP的生理意义
?① 能量：控制能量
?② 与物质中间代谢联系
?③ 是细胞内 NADPH重要源泉
四、乙醛酸循环途径
油料植物种子萌发时, 脂肪酸 → 糖
五、二羧酸循环（ DCA）
?普遍有在于微生物植物中有, 较少在低
等植物是 TCA的补充途径
六、光呼吸途径（乙醇酸代谢途径）
topic 5.2.3 电子传递链的多样性
?呼吸链
?氧化磷酸化
topic 5.2.4末端氧化酶的多样性
1．细胞色素氧化酶
?主要的末端氧化酶与多条链相联系, 占整个化
酶的 50%
?普遍存在于各种组织, 幼嫩组织中最活跃,
?正常情况下植物的主要末端氧化酶, 与 O2亲和
力很高
?低 O2情况下保证呼吸代谢正常退化
?耗 O2里的 3/4由此 E承担
2 抗氰氧化酶（交替氧化酶）
?对氰化物不敏感, 氧化磷酸化作用相对
较低, 称为产热或放热呼吸, 形成 ATP
少, 能量主要以热量散失 。
?广泛存在于高等植物和微生物, 还有玉
米, 豌豆, 绿豆的种子, 马铃薯的块茎,
胡萝卜的块根
?主要存在于, 天南星科海芋属 睡莲 等
沼泽植物
海芋属
?佛焰长序, 早春开花, 为了保证传粉,
这种产热呼吸保证植物在早春温度较低
时完成发育, 同时放热使恶臭散发, 吸
引苍蝇, 帮助传粉
?见 Essay 11.3
作用
?（ 1） 可达 1000—15000微升 /O2/鲜量 /小时
?可使温度上开至 40℃
?（ 2） 促使种子萌发
?（ 3） 分流电子的作用, 降低 满溢效应
?满溢效应 在细胞主路电子处于饱和状态
时, 细胞色素主路电子传途径发生满溢,
TCA循环较迅速时, 抗氰呼吸相对开高 。
3 多酚氧化酶
?荔枝的储藏：必须抑制酶活
?芒果的储藏
?樱桃, 水蜜桃：
?（ 1） 采取早, 中, 晚育种的樱桃, 分期
上市
?（ 2） 加工成缸头
?烟草：金黄色：迅速脱水, 抑制多酚氧
化酶的活性
?黑褐色
?在果品的保鲜, 缸头, 加工中多涉及此
酶的活性
4 抗坏血酸氧化酶
在胚胎发育中, 酶活
?在果蔬加工中, 抑制此酶活
5 黄素氧化酶
?见书
?注意电子传递链和末端氧化酶的多样性
?见书
电子传递链图解
酶 金属辅
基
辅酶 定位 与 o2亲和
力
与 ATP偶
联
细胞色素氧化酶 血红素
Fe
NAD 线粒体 极高 +++
交替氧化酶 非血红
素 Fe
NAD 高 +
酚氧化酶 Cu NADP 细胞质 中 —
抗坏血酸氧化酶 Cu NAD 低 —
乙醇酸氧化酶 NAD 乙醇酸
氧化体
低 —
几种末端氧化酶主要特性比较
?In addition to the five standard
protein complexes found in nearly all
other mitochondria,the electron
transport chain of plant mitochondria
contains five additional enzymes
marked in green,
?None of these additional enzymes
pump protons,
?Specific inhibitors,rotenone鱼藤酮
for complex I,antimycin for complex
III,cyanide氰化物 for complex IV,and
salicylhydroxamic acid (SHAM) for
the alternative oxidase,are important
tools to investigate the electron
transport chain of plant mitochondria,
Topic 5.3
The Alternative Oxidase
?The presence of the alternative
oxidase (AOX) is one of the features
that sets plant (and fungal)
mitochondria apart from mammalian
mitochondria.
?This enzyme has therefore received a
lot of attention from plant scientists
? we now have a fairly good
understanding of the regulation of its
activity
?quantifying the AOX activity
? the role of the AOX in whole plant
respiration
The Structure
? The alternative oxidase is a quinol对苯二酚
-oxygen oxidoreductase and it does not
pump protons,
? The oxygenase transfers electrons from
ubiquinone泛醌，辅酶 Q to oxygen and
generates water as the end product of the
reaction so four electrons must be
transferred to oxygen,
?The precise mechanism for this is
not known,but the protein has iron
binding motifs,so the oxidation
reaction probably requires Fe
?The functional form of the enzyme is
a dimer,with the two polypeptides
either covalently or non-covalently
bound to each other,
?predicted structure places the
protein in the inner mitochondrial
membrane,with the active site and
the regulatory cysteines exposed to
the matrix,
The Amount and Activity of the AOX
Are Carefully Regulated
? The AOX does not pump protons,so when
electrons from NADH oxidation flow
through the AOX,at least two of the three
sites of proton translocation are bypassed,
Therefore,energy conservation in the
form of ATP is much smaller when the
OAX is active,
? The activity of the AOX must therefore be
carefully regulated,
?There are several AOX isoforms in
some plant species,The relative
amounts of three isoforms of AOX
vary with age in soybean cotyledons
子叶,the best-studied developmental
system,
The total AOX amount increases with
age,as does the capacity of the AOX
pathway
Treatment of cell cultures with
antimycin A,which inhibits complex
III,or with H2O2,which causes
oxidative stress both induce AOX
expression
?The activity of AOX is also stimulated by
2-oxo含氧的 organic acids,in particular
by pyruvate丙酮酸,
?This may be a feed-forward mechanism
that upregulates the capacity of the
electron transport chain when the
glycolytic end product is available,（ 即
防止满溢效应）
AOX Activity Can Be Measured In Vivo
?For many years,benzhydroxamic
acid derivatives,(e.g.,
salicylhydroxamic acid (SHAM),were
used to quantify the capacity and
activity of the AOX pathway in both
isolated mitochondria and intact
tissues.
AOX capacity
?AOX capacity was determined from
the rate of respiration in the
presence of KCN,which blocks the
cytochrome pathway,and corrected
for residual respiration in the
presence of both KCN and SHAM.
AOX activity
?AOX activity was determined from
the decrease in the rate of respiration
when SHAM was added in the
absence of KCN,
?The assumption was that the
cytochrome pathway was always
activated first and that the AOX would
be engaged only when the cytochrome
pathway was saturated
?However,as we have seen above,this
assumption is not correct,
?A better method for measuring AOX
activity is now available,It makes use of
the fact that cytochrome c oxidase and
AOX do not discriminate against 18O
relative to 16O to the same extent.
?The so-called oxygen discrimination of
the sample (tissue or mitochondria) can
be measured by mass spectrometry
? (1) with KCN to resolve the oxygen
discrimination by AOX
? (2) with SHAM to resolve the oxygen
discrimination by cytochrome c oxidase
? (3) without inhibitors to resolve the
discrimination value resulting from the
activity of the both enzymes,
?From these values the percentage
contribution by AOX and cytochrome c
oxidase to the total uninhibited rate of
respiration can be calculated.,
The Alternative Oxidase has Several
Functions
Function 1
The AOX pathway appears particularly
active in thermogenic产热的 flowers and
it is primarily responsible for heat
production
?Respiration through the cytochrome c
oxidase system cannot generate an
appreciable increase in tissue
temperature,
Function 2
?The alternative oxidase may also work as
a bypass to oxidize NADH and FADH2
under ADP-limiting conditions under which
the cytochrome oxidase pathway is
restricted,
?In this way,the citric acid cycle and the
glycolytic pathway can continue to run and
provide the cell with biosynthetic
precursors,
Function 3
?The AOX pathway also limits the
formation of reactive oxygen species
(ROS),ROS are formed as byproducts
of electron transport under aerobic
conditions
?ROS can cause damage to proteins,
lipids,and DNA and the cell must
therefore limit their formation,
?AOX helps prevent overreduction of the
electron transport chain and thus
lowers ROS production
?Maxwell demonstrated the importance
of the AOX for limiting ROS formation
in living cells,
?They measured the ROS level in a wild-
type tobacco cell culture and in cells in
which the amount of AOX was either
overexpressed or reduced by
antisensing,
?Overexpression of AOX lowered the
steady state level of ROS,whereas
underexpression caused a five-fold
increase in cellular ROS,
?This result also points to the
mitochondrion as an important site of
ROS generation in plant cells.
Topic 5.4 Temperature Regulation by
Thermogenic Flowers
?These groups are all primitive原始 seed-
plants with large,fleshy肉质的 floral
structures that are often associated with
beetle,bee or fly pollinators,
?Heat production is usually thought to
enhance the production and dispersal of
floral scents气味 that make the plants
more attractive
?or be a reward to insects by keeping them
warm in floral chambers where they
remain overnight,
Example
?Some species,such as the arum海芋属
lilies百合,are so intensely thermogenic
产热 that their flowers can increase up to
35° C above the surroundings,
?in Brazil,the inflorescence of
Philodendron selloum is capable of
warming to over 40° C at air
temperatures close to freezing.
?Skunk cabbage,Symplocarpus foetidus
can maintain temperatures above 15° C
when the air temperature drops to –
15° C,and it often melts the snow
around the plant
Substrate
? the substrate for respiration is
starch,often imported from other
parts of the plant,but in P,selloum,
the substrate is lipid that is stored
in the florets prior to blooming,
?Analysis of heat production by direct
calorimetry and respirometry show that
all of the energy in the substrates ends
up as heat.
?Although there is the possibility of some
energy going into phosphorylation of
ADP or into synthesis of floral
structures,this appears to be negligible,
Respiratory rates
?The respiratory rates of some
thermogenic flowers are the highest
among plants,and in fact exceed even
those of warm-blooded animals.
? For example,the tissue of Arum maculatum
produces up to 0.40 Watts per gram (W g–1),
while a flying hummingbird produces only
0.24 W g–1,
? At an air temperature of 10° C,a 125 g
inflorescence of P,selloum produces about
five times the amount of the heat of a 125 g rat
under the same conditions,
? Such high rates of heat production demand a
good supply of oxygen.
Supply of oxygen
? In the florets of P,selloum,this is achieved by
diffusion through a network of tiny
intercellular gas spaces that permeate the
tissue to the center.
? The demand for oxygen is so high,that the
oxygen partial pressure at the center of the
floret drops to about one-quarter of
atmospheric,but remains just above the
critical level where oxygen uptake becomes
diffusion-limited,
?A few species of the most powerfully
thermogenic flowers also exhibit
temperature regulation,that is,they
regulate the rate of respiration and
achieve a relatively constant
temperature in the flower,regardless of
external air temperature
?In these cases,the respiratory rate
increases almost linearly as the ambient
环境 temperature drops,and the mean
temperature of the flower is almost
constant
Physiological
thermoregulatory温度调节
control mechanism
? The physiological thermoregulatory control
mechanism is not known
? It is certain,however,that it is unlike the
mechanism in birds and mammals that relies
on a complex nervous interaction between
temperature receptors,central nervous
system processing,and control of organs that
affect rates of heat production and loss.
? In plants,the regulation must occur at a
strictly biochemical level,
?One possible regulator is salicylic acid水
杨酸,which is known to be involved in
triggering thermogenesis in arum lilies,
?Another possibility is the AOX
The reason of
Temperature regulation
? In animals,its adaptive value is to maintain
high and stable body temperatures that
permit them to be active under cold
conditions,
? Compared to thermally compliant
poikilotherms (cold-blooded animals),animal
homeotherms are able to find more food,
compete better for territory and mates,and
reproduce faster—all evolutionarily
advantageous in many circumstances
?Temperature regulation is not a
requirement to enhance the
vaporization of scents; unregulated high
temperatures would suffice满足
?there is increasing evidence that
thermoregulation in flowers is a service
offered as a reward to insect visitors,
?Large flying insects,chiefly beetles,
which require high body temperatures
during activity,often pollinate first,
thermoregulatory flowers
?Second,these insects often remain in
floral chambers for about a day,and
thermoregulation coincides with this
period,
?During their residence,they mate,eat,
and digest—activities that benefit from
high temperatures,
?If beetles inside P,selloum had to
produce their own heat actively to raise
body temperatures to 35° C,they would
use about 50 times the amount of
energy as they would during passive
heating inside a thermogenic flower.
?While many non-thermoregulatory
flowers offer energy in the form of
nectar,starch,or pollen to their insect
visitors,thermoregulatory flowers can
offer energy directly as heat,
? studies of the dragon lily Dracunculus
vulgaris show conclusively that
thermoregulation is not associated with
scent production,but more likely with
beetle entrapment
? The 80 cm inflorescence of this arum lily
consists of a floral chamber and a large spike
钉,called the appendix,protruding above it,
? During the first day of blooming,the
appendix produces a powerful scent of rotting
meat that attracts carrion beetles吃腐肉的甲
虫,which fall into the chamber and provide
pollen to receptive female florets小花,
? They remain in the chamber overnight while
the female florets become nonreceptive,and
they are released the next day after being
showered with pollen from the male florets,It
is significant that the appendix is strongly
thermogenic,but not thermoregulatory,Its
heat is entirely lost by evaporation of water
carrying the scent,and respiration falls with
decreasing ambient temperature,
?On the other hand,respiration in the
floral chamber rises with decreasing
ambient temperature,the characteristic
of thermoregulatory tissue,
?Because the site of thermoregulation is
associated with the site of trapped
beetles rather than the scent production,
it is consistent with the idea of an
energy reward,
Topic 5.5 FoF1-ATPases,The World's
Smallest Rotary Motors
?FoF1-ATP synthases (also called F-
ATPases) are present in the inner
membranes of mitochondria,
chloroplasts,and bacteria,
?these large,multisubunit enzymes
consist of a water-soluble catalytic
complex (F1) attached to an integral
membrane protein complex (Fo) that
transports protons across the
membrane
?The F1 complex is composed of at
least five different types of subunits
(three α,three β,one γ,one δ,and
one ε),When the F1 complex is
dissociated from the membrane,it is
active as an ATPase,
?In fact,under the appropriate
conditions the intact FoF1-ATP
synthase can run in reverse and act
as a proton pump,using the energy
of ATP hydrolysis to move H+ across
the membrane
Binding-change
mechanism
?1,The major energy-requiring
step is not the synthesis of
ATP from ADP and Pi,but the
release of ATP from the
enzyme,
?2,Substrate is bound and
products are released at three
separate but interacting
catalytic sites,corresponding
to the three catalytic subunits
(β subunits),Each catalytic
site can exist in one of three
conformations,tight,loose,or
open,
?3,The binding changes are coupled
to proton transport by rotation of the
γ subunit,That is,the flow of protons
down their electrochemical gradient
through the Fo complex causes the γ
subunit to rotate.
?The first two predictions of the
binding-change model are supported
by many lines of evidence,mainly
kinetic studies,and are now
generally accepted,
?However,the prediction of a
rotary mechanism for coupling
proton flow to ATP synthesis has
been more difficult to
demonstrate,Recently,two major
breakthroughs have led to
confirmation of the third
prediction as well.
The first breakthrough
?the determination of the crystal
structure of the F1-part of bovine
mitochondrial ATPase by the
laboratory of John Walker in
Cambridge,England
?The crystal structure showed that the
three catalytic β subunits differ in
their conformations and in the
nucleotide bound to them,consistent
with the binding-change mechanism,
?the γ subunit is inserted like a shaft
轴 through the center of the catalytic
complex,which consists of three α
subunits and three β subunits
arranged alternately in a
doughnutlike炸油圈饼 似的 structure,
? Moreover,the interface between the γ
subunit and the α and β subunits is highly
hydrophobic不亲水的,
? The hydrophobicity of the interface
minimizes the interactions between the
subunits,consistent with the rotation of
the γ subunit within the hole formed by
the catalytic complex,
?In other words,the γ subunit looks like a
molecular bearing轴承 lubricated by a
hydrophobic interface,
The second discovery
?Definitive demonstration of rotation
requires a video recording of the
spinning of the enzyme in real time,
?But although they are large for
proteins,F1-ATP synthases are still
far too small to be visualized in a
light microscope.
? To visualize the rotation of the enzyme,
Masasuke Yoshida and his colleagues at
the Tokyo Institute of Technology came up
with an ingenious精巧 method to make the
enzyme much larger than it is,
? they attached an actin filament labeled
with a fluorescent dye to the base of the γ
subunit using another protein as a "glue."
? They then attached the F1 complex upside
down to a glass surface,
?If the γ subunit rotates with respect to the
catalytic complex,the actin filament
should swing around with it,
? Since the filament is very long compared
to the ATP synthase (about 1 μm),its
rotation should be visible in a
fluorescence microscope.
?In other words,the fluorescently
tagged actin filament,which is large
enough to visualize in a light
microscope,reports the rotation of
the γ subunit
?The results were spectacular!
? When ATP was added to the
modified enzyme,the actin filaments
were seen to swing around in a circle
at as much as 4 revolutions per
second in a fluorescence microscope
?To give some idea of scale,if you
were a γ subunit,this rotation rate
would be equivalent to swinging a
several hundred meter-long rod
around your head at 4 revolutions
per second in water
?However,the measured velocity is
undoubtedly an underestimation of
the actual velocity in vivo,because
of the enormous torque扭矩 required
to swing such a large mass,
? For their contributions to elucidation of
the mechanism of ATP synthesis,Paul
Boyer and John Walker shared half the
Nobel prize in physiology or medicine in
1997,
? The other half went to Jens Skou for his
pioneering work on the K+,Na+-ATP
synthase,the mammalian counterpart of
the plant plasma membrane H+-ATP
synthase
The binding-change mechanism
A method for visualizing rotation of the γ subunit
Sequential images of the rotating actin filament attached
to the γ subunit
as viewed in a fluorescence microscope,
Topic 5.3影响呼吸作用的因素
?呼吸速率和呼吸商
?氧气
?二氧化碳
?水
?温度
第五章复习题
?名称解释：
?呼吸链 呼吸系数 呼吸控制比 抗氰呼吸
末端氧化酶
?1,有氧和无氧呼吸各有何特点
?2,比较光合作用与呼吸作用
?3,植物呼吸代谢多样性的基本内容？ 有
何生理意义？
?4,如何判断呼吸底物是经 EMP-TCA或
PPP途径降解？ 细胞内糖降解首先进入
哪种途径是受什么因素调节？
?5,HMP途径有何生理意义？
果蔬储藏时呼吸作用的二重性
?呼吸作用是一切生命活动的重要标志,
果蔬在储藏过程中的一切生理变化, 都
靠呼吸作用来维持 。 它们离开了栽培条
件, 不能进行光合作用, 无法制造养分 。
呼吸所产生的能量, 一部分用来维持自
身的生命活动, 使之保持自身对外界微
生物的侵入具有抵抗能力, 也使自身对
表皮伤口有一定的愈合能力；另外, 一
部分以热能的形式释放, 即呼吸热 。
?呼吸作用既是本身生存的表现，又是自
身消亡的动力。
?储藏的 目的：尽量延长前者的时间，阻
止后者的出现。
苹果贮藏
?苹果是我国市场上主要果品之一，也是
各地果品贮藏的重要种类苹果的品种很
多，供市场的主要品种就有了 30多个，
按成熟期分为早熟、中熟、晚熟三类，
?早熟品种在 6月下旬至 7月下旬成熟, 有
祝光, 伏花皮, 黄魁 。 由于生长期短,
果肉组织不够紧密, 因而不耐储藏, 一
般不作为储藏品种来用 。
?中熟品种主要有红玉, 元帅 （ 红香蕉 ） 金
冠 （ 黄元帅, 金帅 ）, 红星, 秋花皮等,
在八九月间成熟, 风味较好, 较耐贮藏 。
随着冷库的建设, 这类苹果的贮藏日益增
多
?晚熟品种主要有国光, 鸡冠, 青香蕉, 印
度青红 。 在 10月至 11月上旬成熟, 质量一
般较好, 耐贮藏, 是贮藏的主要品种 。
一、对贮藏条件的要求
?贮藏苹果的适宜温度为 0— 1℃, 适宜空
气相对湿度为 85— 90%,适宜气体成分
为：氧浓度 2-4%,二氧化碳为 3-5%。
?因黄元帅等中熟苹果在采摘时正值秋老
虎季节，气温果温都较高
?据试验，苹果在 4.4℃ 下成熟速度比在
0℃ 条件下快一倍 ;在 9℃ 下比要 4.4℃ 快
一倍；在 21℃ 下又比 9℃ 下快一倍也就是
说，苹果采摘后在室外 21℃ 放一天，就
等于缩短了 7-10天的冷藏寿命。
?因此, 采后及时预冷降温, 尽快散掉果
实所带的田间热, 降低果实内的呼吸强
度, 对保证后期质量, 延长贮藏寿命具
有非常重要的作用 。
?预贮 对果, 蔬贮藏都有重要 。
?红香蕉苹果在贮藏中容易出现“返砂”现象，
除与品种特性有关外，与采后的延时预冷降温
关系重大
?所谓“返砂”是指果皮开裂果肉外露，口感绵
软的现象，主要是因为果实中的原果胶分解为
水溶性果胶，与纤维素分离，使细胞间的结合
松弛，果实于是由硬变软，失去清脆的风味
?如果采摘后及时预冷降温，降低其呼吸强度，
则可以减缓“返砂”的发生。
二、贮藏方法
?1 适时采收
?采收标准
?以红香蕉苹果为例
?可溶形固形物 10% 以上, 果实硬度
16.5%磅 /平方米, 着色面积 95%,用淀
粉染色时, 果心线内的部分不在被染色 。
从时间上算, 一般为果树盛长后的 147天
左右 。
?2,准备好包装材料
?a.塑料 （ 无毒聚乙烯 ） 袋
?不是聚氯乙烯
?b,硅胶窗
?硅胶窗
?用一种透气性极强的薄膜塑料一硅橡胶,
做成气体交换窗 （ 硅窗 ） 镶嵌在普通的
包装薄膜帐 （ 袋, 或库, 窖的气窗上 ）
即可以自动调节贮藏环境中 O2和 CO2浓
度, 这种气调方式称为硅窗气调
?CO2与 O2的透气比为 5,1。这种透气比
对贮藏水果、蔬菜很适合，只要在包装
塑料上镶嵌一定面积的硅橡胶，加上适
宜低温，即可达到保护目的。
?用硅窗气调贮藏果蔬能省去人工调节 O2
和 CO2浓度的工作, 能够节省 N2和有关
设备, 具有方便可靠投资少特点 。
?3．贮藏前药剂处理
?① 苹果采收后, 用 6%的 Cacl2浸果, 可
提高果实硬度, 降低生理病害发病率,
好果率比对照提高 7-8%。
?② 溴氯烷薰蒸
?溴氯烷是一种薰蒸型广谱抗药剂, 有较好的杀
菌和抑菌作用, 对青霉菌等有很好的杀伤效果 。
?从苹果品种来看, 对抗菌能力差的苹果, 薰蒸
效果越明显, 如果在薰蒸后对果实进行包装,
以采用纸包装的效果好 。 这是因为与塑料包装
相比, 还有透气性好, 降温快等优点 。
?使用时, 每百斤果实用 20克溴氯烷, 防病效果
好
?4,贮藏方法
?（ 1） 硅窗气调法
?用塑料薄膜制成塑料帐，装上硅窗，框
架放在塑料底垫上，苹果放在框架中，
每层边高可达 1.2米，可放多层，罩上塑
料帐，大帐垂边与底边叠几圈、压紧、
造成贮存苹果的密封环境
?苹果装在帐内，由于苹果呼吸，帐内氧
气逐渐减少，二氧化碳浓度高于大气，
这样就形成两种气体与大气的正负压差，
帐内 CO2由硅窗排出,O2从大气中透入，
当氧气含量低于 2%时，可打开气调帐的
气体平衡孔，放进少量空气，补充氧气。
?硅窗气调法贮藏苹果, 贮存的时间广,
损耗较小, 不耗能量, 不需大设备, 适
合于广大农村采用 。
?2,纸箱贮藏
?每个苹果用白纸包好,0 ℃ -2℃ 贮藏，
检查 除腐烂果
其他章节的知识点
光敏色素
?红外光和远红外光都可影响植物光形态
建成, 其受体是光敏色素, 一种可溶于
水的色素蛋白, 它广泛存在于除真菌以
外的低等和高等植物中, 对光周期, 花
诱导等都有重要影响 。 光形态建成指依
赖于光的控制细胞分化, 形态结构以及
器官与组织的建成 。
组织培养
?指在无菌条件下，分离并在培养基中培
养离体植物组织的技术。
?愈伤组织,一团无分化状态的细胞
?分化与脱分化
植物激素的种类及功能
生长素, 3 -吲哚乙酸 （ IAA）, 萘乙酸
（ NAA）, 2,4-二氯氧乙酸 （ 2,4-D）
?赤霉素, GA
?赤霉素和生长素的作用
?细胞分裂素, 6-苄基嘌呤 （ 6-BA）, 激
动素 （ KN）, 玉米素 （ zeatin）
?细胞分裂素与生长素的比值
?脱落酸 （ ABA）
?乙烯,成熟激素
? 乙烯利
春化作用
?低温对植物开花或促进开花作用
呼吸骤变,
?当果实成熟到一定程度时, 呼吸速率首
先是降低, 然后突然增高, 最后又下降,
此时果实进入完全成熟 。 这个呼吸高峰,
称为呼吸骤变 respiratory climacteric）
即果实的后熟
? 具有呼吸骤变的果实有：苹果, 香蕉,
梨, 桃
? 不具有呼吸骤变的果实有：橙, 凤梨等
基因芯片：
?又叫 DNA微陈列, 是指固定在固相载体
上的高密度 DNA微点列, 具体地说就是
把大量靶基因或寡核苷酸片段有序地,
高密度地排列在玻璃, 硅等载体上, 称
之为基因芯片 。
?基因芯片的应用，给生命科学的研究带
来了革命的推动，它具有高通量、大规
模、高度并行性、快速高效、高灵敏度、
蕴藏高价值以及高度、自动化等诸多优
点。
