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1.
The present work comprises a study of 6 wheat varieties of various degrees of cold resistance. They are: 2 winter varieties, Nungta 183 and Huapei 187; 2 spring varieties, Nanta 2419 and Piyü; and 2 intermediate varieties (according to their winter hardiness), Pima No. 1 and Pingyüan 50. All these varieties were cultivated under the same natural conditions. Cytological changes of each of the varieties were studied comparatively at different stages of the overwintering period. In addition, certain morphological and physiological features of the above mentioned varieties were also studied. With the temperature gradually falling in autumn, the rate of the cell divisions and the physiological activities of the nucleoli of the winter varieties decreased, the growth of the plants and the development of the apical cones were suppressed, and so more storage materials were left. The less hardy and non-hardy varieties, on the other hand, retained their cytophysiological activities and high growing rate, so that the stored materials were much less than those left in the winter varieties. However the non-resistant varieties could not withstand the winter frost and survived no more. The plants of the less hardy varieties were partly killed by winter frost. When the temperature dropped further in winter, plasmolysis gradually appeared in the cells of the tillering nodes of the cold resistant wheat plants, and it disappeared with the return of the warmer weather. The degrees of the plasmolysis in different varieties were found proportional to their cold hardiness, and no plasrnolysis was observed in the spring wheat. Thus a correlation apparently exists between the plasmolysis and the cold resistance in wheat. In winter, the vacuoles of the young leaf cells and of the cells of the primary meristematic tissues of the apical cones became smaller and smaller, while a dense reticular structure appeared in the cytoplasm. In spring, the vacuoles restored, and the reticular structure disappeared. It seems that the occurrence of the reticular structure in the winter season is also closely correlated with the cold resistance of the wheat plants. It was found that the nuclei and the chloroplasts of the winter varieties were more resistant to cold than those of the less resistant and non-resistant varieties. The stability of these structures increased in hardened condition. Morphological changes of the chloroplasts of the young leaf cells occured from autumn to winter, they were transformed from polymorphic to uniformly globular. The chloroplasts of some cells were balling together, however, they actually retained their individualities. The chondriosomes increased in size and quantity during the hardened period. They became short and thick, some were in globular form or they clumped together in severe winter, and gradually restored when warmer weather arrived in the spring. The correlations of the mitosis, the plasmolysis, the appearance of the reticular structure in the cytoplasm and the stability of the nuclei with the cold resistance of the wheat were discussed.  相似文献   

2.
Resistance to pink snow mould, caused by Microdochium nivale, was investigated in four resistant winter wheat lines from the USDA World Cereal Collection (CI9342, CI14106, PI173440 and PI181268) and three Nordic wheat lines (Bjørke, Rida and V1004). Pink snow mould resistance was tested in non‐hardened and cold‐hardened plants incubated under artificial snow cover and in detached leaf segments mounted on water agar and incubated at either 3°C in darkness or at room temperature with light during the day. The wheat lines CI9342, CI14106 and PI181268 were more resistant than the Nordic lines, both before and after cold hardening. Thus, although cold hardening strongly increases the level of snow mould resistance in all the wheat lines, some resistance mechanisms are also present prior to cold hardening in some of the resistant lines. CI9342, CI14106 and PI181268 also had a higher level of resistance than the other lines in the detached leaf assay, indicating that these lines have some resistance mechanisms acting in the leaves. The resistance of PI173440 was expressed only in intact hardened plants and not in non‐hardened plants or in detached leaves. This indicates that this line relies on cold hardening‐related changes in the crown for its resistance. In the detached leaf assay the rate of lesion development varied greatly between leaves of different order. The highest correlation with the whole plant test was obtained when using secondary leaves and incubation at 3°C in the dark.  相似文献   

3.
The localization and distribution of the glycoproteins in cellular membranes of strong cold hardy winter wheat (Triticum aestivum L. cv. Yanda 1817) seedlings were studied employing the modified cytochemical method using Concanavalin A-Horseradish peroxidase conjugates. The results obtained showed that the reaction products of Horseradish peroxidase activity which indicated the presence of glycoproteins appeared as individual particles distributed at plasmalemma, endoplasmic reticulmn, nuclear envelope and tonoplast in the leaflet cells of the seedlings grown under optimum temperature 25℃ day/20℃ night. After cold acclimation of the seedlings at low temperature during late autumn and early winter, the quantity of glycoproteins distributed in endoplasmic reticulum and nuclear envelope was significantly increased, and glycoproteins were transported into almost all of the plasmodesmata. At some sites of mitochondria and plastides newly formed glycoproteins were observed. However, no distribution of glycoproteins was for,nd in Golgi bodies during the whole observations. The role of glycoproteins for the development and stability of cold resistance in plant through blocking up the plasmodesma passage in the overwintering period of winter wheat seedlings, and the possible differences of the synthetic site and transportation pathway of glycoproteins between animal and plant systems were discussed.  相似文献   

4.
Two varieties of winter wheat ( Triticum aestivum L.) differing in freezing resistance ("Holme" from Sweden, freezing resistant, and "Amandus" from Germany, less freezing resistant) were hardened for five weeks by gradually reducing the day/night temperature from 20°C/15°C during the first week to 2° C/0° C during the fifth week and the photoperiod from 15 to 9 h. This treatment increased the freezing resistance of both varieties in comparison to unhardened control plants. Hardening caused an increase in osmolarity of cell sap and in the levels of proline and abscisic acid (ABA). Increase in osmolarity preceded the increase in ABA level, and proline levels increased later than ABA levels. Holme had higher values of osmolarity as well as higher levels of ABA and proline. but the differences between the two varieties were significant only for proline. Since the pressure potential remained constant or increased slightly during the hardening period, it is suggested that the accumulation of ABA is due to the hardening process and not to simple water stress caused by cold-induced inhibition of water uptake by the root.
Spraying hardened plants with 10−4 M ABA 24 h before a freezing test increased freezing resistance in both varieties, but did not obliterate the differences in freezing resistance between the two varieties. Spraying hardened plants with an aqueous proline solution (10%, w/v) was without effect on freezing resistance. It is concluded that the hardening procedure causes an accumulation of ABA in winter wheat leaves and that ABA is involved in the chain of events leading to freezing resistance.  相似文献   

5.
Jian LC  Sun LH  Dong HZ 《Plant physiology》1982,70(1):127-131
A cytochemical study of ATPase activity in the cells of cold hardened and nonhardened winter wheat (Triticum aestivum L. cv. Nongke No. 1) seedlings was carried out by electron microscopic observation of lead phosphate precipitation. ATPase activity associated with various cellular organelles was altered during cold hardening. (a) At 22°C, high plasmalemma ATPase activity was observed in both cold hardened and nonhardened tissues; at 5°C, high activity of plasmalemma ATPase was observed in hardened tissues, but not in unhardened tissues. (b) In nonhardened tissues, tonoplast and vacuoles did not exhibit high ATPase activity at either 22 or 5°C, while in hardened tissues high activity was observed at both temperatures. (c) At 5°C, ATPase activity of nucleoli and chromatin was decreased in hardened tissues, but not in nonhardened tissues. It is suggested that adaptive changes in ATPase activity associated with a particular cellular organelle or membrane may be associated with the development of frost resistance of winter wheat seedlings.  相似文献   

6.
The interaction between light and temperature during the development of freezing tolerance was studied in winter wheat (Triticum aestivum L. var. Mv Emese). Ten-day-old plants were cold hardened at 5 degrees C for 12 days under normal (250 micromol m(-2)s(-1)) or low light (20 micromol m(-2)s(-1)) conditions. Some of the plants were kept at 20/18 degrees C for 12 days at high light intensity (500 micromol m(-2)s(-1)), which also increased the freezing tolerance of winter wheat. The freezing survival rate, the lipid composition, the antioxidant activity, and the salicylic acid content were investigated during frost hardening. The saturation level of hexadecanoic acid decreased not only in plants hardened at low temperature, but also, to a lesser extent, in plants kept under high light irradiation at normal growth temperature. The greatest induction of the enzymes glutathione reductase (EC 1.6.4.2.) and ascorbate peroxidase (EC 1.11.1.11.) occurred when the cold treatment was carried out in normal light, but high light intensity at normal, non-hardening temperature also increased the activity of these enzymes. The catalase (EC 1.11.1.6.) activity was also higher in plants grown at high light intensity than in the controls. The greatest level of induction in the activity of the guaiacol peroxidase (EC 1.11.1.7.) enzyme occurred under cold conditions with low light. The bound ortho-hydroxy-cinnamic acid increased by up to two orders of magnitude in plants that were cold hardened in normal light. Both high light intensity and low temperature hardening caused an increase in the free and bound salicylic acid content of the leaves. This increase was most pronounced in plants that were cold treated in normal light.  相似文献   

7.
Historical datasets have much to offer. We analyse data from winter wheat, spring and winter barley, oil seed rape, sugar beet and forage maize from the UK National List and Recommended List trials over the period 1948–2007. We find that since 1982, for the cereal crops and oil seed rape, at least 88% of the improvement in yield is attributable to genetic improvement, with little evidence that changes in agronomy have improved yields. In contrast, in the same time period, plant breeding and changes in agronomy have contributed almost equally to increased yields of forage maize and sugar beet. For the cereals prior to 1982, contributions from plant breeding were 42, 60 and 86% for winter barley, winter wheat and spring barley, respectively. These results demonstrate the overwhelming importance of plant breeding in increasing crop productivity in the UK. Winter wheat data are analysed in more detail to exemplify the use of historical data series to study and detect disease resistance breakdown, sensitivity of varieties to climatic factors, and also to test methods of genomic selection. We show that breakdown of disease resistance can cause biased estimates of variety and year effects, but that comparison of results between fungicide treated and untreated trials over years may be a means to screen for durable resistance. We find the greatest sensitivities of the winter wheat germplasm to seasonal differences in rainfall and temperature are to summer rainfall and winter temperature. Finally, for genomic selection, correlations between observed and predicted yield ranged from 0.17 to 0.83. The high correlation resulted from markers predicting kinship amongst lines rather than tagging multiple QTL. We believe the full value of these data will come from exploiting links with other experiments and experimental populations. However, not to exploit such valuable historical datasets is wasteful.  相似文献   

8.
通过对冬季室内和室外分别生长30d的冬小麦在节律性和非节律性融冻变温过程中抗氧化酶活力和渗透调解物含量变化的分析,揭示其在冬小麦适应日融冻胁迫中的作用。结果表明:生育期不同的室内(均温11℃,拔节期)和室外(均温1℃,分蘖静滞期)冬小麦叶片抗氧化酶和脯氨酸对日光强和温度节律变化的响应趋势是一致的,即随日出而增高,中午气温较高时最高,日落而降低;在非节律性变温处理中,室外冬小麦抗氧化酶活力和脯氨酸含量随气温上升至18℃而增高,气温迅速下降到-2.5℃而降低,经历冻-融-冻胁迫冬小麦生长良好。室内冬小麦抗氧化酶活力随气温降低到-6℃,叶片结冻,迅速下降,气温升高到18℃而增加,经历融-冻-融胁迫后植株死亡;室外冬小麦光合速率(Pn)和比室内的低,而抗氧化酶活力高于室内;冬小麦快速提高抗氧化酶活力和脯氨酸含量,抑制氧自由基积累、维护细胞水分平衡,这在适应冬季节律性融冻胁迫中起重要作用;暖冬中冬小麦较高的Pn和较低的抗氧化酶活力可能是引起冬小麦在"倒春寒"中死亡的生理原因。  相似文献   

9.
不同品种小麦叶片对拔节期低温的生理响应及抗寒性评价   总被引:6,自引:0,他引:6  
以黄淮海麦区参加区试的24个小麦品种为材料,分析了拔节期低温胁迫对其叶片相对电导率、可溶性糖含量、可溶性蛋白含量、游离脯氨酸含量、丙二醛(MDA)含量以及超氧化物歧化酶(SOD)和过氧化物酶(POD)活性的影响。结果表明,低温胁迫后,叶片相对电导率、可溶性糖含量、脯氨酸含量、MDA含量、SOD活性和POD活性均高于对照(P0.01),而可溶性蛋白含量低于对照(P0.01)。小麦叶片各指标存在极显著的品种间差异(P0.01)。以叶片各指标的相对值作为抗寒性指标,采用隶属函数法和极极点排序法计算参试品种的平均隶属度值为0.19—0.63,综合排序值为1.66—4.08。通过K-means聚类,将24个小麦品种聚为5类。其中良星619、丰德存麦1号、B07-4056、石H083-363、山农055843和良星99等6个品种抗寒性最强,宿553、陕农509、A-9、中原6号、徐麦4036、舜麦1718和石麦19等7个品种抗寒性强,尧麦16、C-44、山农05-066、冀麦585和石B05-7388等5个品种抗寒性中等,偃展4110、B-33、B05-6507和石4185等4个品种抗寒性弱,石06-6136和石优20这2个品种抗寒性最弱。相关分析表明,平均隶属度值和综合排序值与相对可溶性糖含量、相对脯氨酸含量、相对POD活性呈正相关(P0.05),与相对MDA含量呈负相关(P0.05)。叶片可溶性糖含量、游离脯氨酸含量、POD活性及MDA含量可以作为拔节期小麦抗寒性的鉴定评价指标。  相似文献   

10.
Both CCC and cold (5°C) treatment gave rise to an increased content of the water-soluble proteins in leaf tissue of the winter rape, irrespective of the day length. This effect was accompanied by a decrease of the insoluble nitrogen compounds content, mainly under theLD (the 16 hour day). The applied retardant also stimulated the consumption of the structural compounds induced by low temperature. Low temperature treatment hardened plants more distinctly than the CCC application. The frost hardening effect of CCC andSD (the 8 hour day) was manifested only at 20°C and it disappeared at 5°C. Changes in frost hardiness were not correlated with the changes in the reducing sugar content and in the reducing ability of the studied tissue. The coincident effect of CCC and cold on the reducing sugar content was observed underSD conditions.  相似文献   

11.
12.
Freezing tolerance of isolated protoplasts of three wheat, varieties which differ from each other in cold resistance has been measured. The results obtained in the present study indicate that the survival percentage of wheat protoplasts after freezing treatment is indirect correlation with the cold resistance of its varieties. It is discussed that the change in plasmolemma plays a role in the mechanism of chilling injury and cold resistance of plants, and the results obtained may be used as an indicator for determining the cold resistance of the plants.  相似文献   

13.
潮滩红树植物抗低温适应的生态学研究   总被引:21,自引:0,他引:21       下载免费PDF全文
采用电导法定量测定了中国东南沿海红树植物叶片的抗寒力变化。结果表明;(1)海南琼山东寨港主要红树种类冬季抗寒力(半致死温度)介于-2.3~-6.8℃之间,其中红树科植物抗寒力较强,多数种类属于低温敏感性相对较弱的L类型;海桑科和楝科红树种类抗寒力较弱,属于低温敏感性较强的H类型。(2)随纬度升高(个别地点除外),秋茄(Kandelia candel)、桐花树(Aegiceras corniculatum)和红海榄(Rhizophors,stylosa)抗寒力增强,呈现种群分化趋势。(3)同一地点,秋茄和桐花树抗寒力有明显季节变化:夏季最低,秋冬两季高于春季。(4)同一群落内,生长于中潮区滩面的秋茄抗寒力强于高潮区,但桐花树抗寒力在各个滩面相差木大。(5)秋茄和桐花树树冠上不同部位叶片的抗寒力不同,由表及里,由上至下,呈降低趋势。红树叶片抗寒力的种群分化、季节变化和部位差异是其趋异适应的结果,有益于红树植物的生存和繁育。  相似文献   

14.
Miniswards of white clover (Trifolium repensL.) varieties Menna,Huia, AberCrest and AberHerald, with contrasting winter hardiness,were established from cloned material in flat boxes. The miniswardswere placed in an unheated glasshouse with natural lightingfor the winter of 1995/96. During this time there were severalperiods of cold weather. The plants experienced temperaturesat least as severe as those experienced by unprotected plantsduring preceding mild winters. Growth measurements carried outmonthly suggested the cloned genotypes were representative ofthe varieties from which they were derived. Growth continuedthroughout the experiment, particularly when expressed as appearanceof new internodes. During the coldest weather these internodeswere short, and the amount of tissue produced was small. Starchconcentration showed a complex pattern of changes during thewinter. Older internodes were the major site of starch storagein the autumn; starch was lost from these internodes duringthe winter and early spring. Starch synthesis also occurred,even during the coldest periods. Starch accumulated in all newstolon tissue. There were significant differences between varieties.AberCrest and AberHerald retained higher concentrations of starchin older stolon tissue, synthesized higher concentrations ofstarch in young tissue and retained these for longer. Therewere few differences in soluble sugar concentrations betweenvarieties, but there were significant changes during the winter.In mid-winter, sucrose and pinitol were at their highest concentrations,whereas reducing sugars were at their lowest concentrations.This study further supports the important role of starch reservesin supporting winter survival.Copyright 1998 Annals of BotanyCompany Trifolium repens; white clover; winter hardiness; starch; sugar; pinitol.  相似文献   

15.
We studied CO2 exchange and phenolic compound production in various organs of unhardened and hardened winter wheat (Triticum aestivum L.) plants. The rates of CO2 assimilation at saturating illumination (photosynthesis) and CO2 evolution in darkness (respiration) declined substantially at the autumnal decrease of ambient temperature. However, because of a higher cold resistance of photosynthesis, the ratio of photosynthesis to respiration rates increased 1.5-fold. These gas exchange changes were accompanied by the accumulation of total soluble phenolics in leaves and a polymeric phenolic compound lignin in roots. We did not observe any changes in the production of either soluble or polymeric (lignin) phenolics in crowns.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 366–371.Original Russian Text Copyright © 2005 by Zagoskina, Olenichenko, Klimov, Astakhova, Zhivukhina, Trunova.  相似文献   

16.
The influence of long and short days during the hardening period on the cold hardiness of perennial ryegrass seedlings was studied as was the relative hardiness of roots and shoots. Hardiness was assessed by the electrolyte release method which was a measure of the amount of damage subsequent to low temperature treatment. Long days promoted hardiness in shoots of Pax 0tofte plants and in one case under short days the roots were found to be hardy. Generally roots were less hardy than shoots in Pax 0tofte and S23 plants hardened under long days for 2 wk. When hardened at the fourth leaf stage for 2 wk at + 5 oC under long day conditions, Pax 0tofte plants were more hardy than those of S23. The long day effect on hardiness was arrived at more rapidly, there being no difference in hardiness after 3 wk in Pax 0tofte hardened under long or short days, whereas a significant degree of hardening was observed after 1 wk of hardening under long days at – 4 oC. The results obtained are discussed in relation to winter kill of grasses in the West of Scotland, and it is considered that root damage is not an important factor in causing winter kill. The promotive effect of long days on hardiness when hardening commences in late autumn is considered an advantage in temperate regions as it may also allow early frosts to be withstood.  相似文献   

17.
Haemagglutinating activity was determined in cell walls and total cell organelles of crown cells of Winter wheat (Triticum aestivum L. ) plants. The effect of fusicoccin (FC) was investigated using fractions obtained from plants hardened for 7 days at 2 degrees C and from untreated plants. FC concentration (5x10(-7) m) increased the frost resistance of the plants. The temporal pattern of lectin activity during hardening could be described by a single-peak curve. In the cell wall fraction, the highest activity manifested itself after one-day hardening, and in the fraction of organelles it peaked after five-days hardening. The carbohydrate specificity of lectins also changed during hardening; cell wall lectins completely lost their capacity for interaction with uridine diphosphoglucose, glucose 6-phosphate, D-galactosamine, and N-acetylglucosamine and the lectins of organelles retained some affinity only for amino sugars. After hardening the test plants, the activity of the lectins increased substantially in the cell walls and plastids, decreased in the nuclei, and was practically flat in mitochondria and microsomes. Consequently, low temperature and FC with their antistress effect improved frost resistance and stimulated the activity of the lectins of some cell structures of the tillering node of winter wheat. A similar action of low temperature and FC in increasing the activity of lectins of plastids was found. Further information was obtained on the subcellular localization of lectins providing additional information on their possible participation in the development of frost resistance of winter wheat.  相似文献   

18.
丛国强  尹成林  何邦令  李玲  高克祥 《生态学报》2015,35(18):6120-6128
为明确不同水分条件下内生真菌对冬小麦苗期生长和抗旱性的影响,以抗旱型小麦品种山农16和水分敏感型小麦品种山农22为材料,利用荧光定量PCR技术检测小麦干旱诱导基因脱水素wzy2的表达量来了解冬小麦在干旱胁迫下相关基因的表达差异,通过测定相关生理指标与酶活性来判断小麦发育及其在干旱胁迫下的生理响应状况。结果表明,与正常水分ND35组相比,接种球毛壳菌(Chaetomium globosum)ND35的干旱处理组小麦的根冠比、总蛋白含量、脯氨酸含量及丙二醛含量等指标显著提高,小麦叶片含水量和可溶性糖含量有所降低。在干旱处理组中,球毛壳菌ND35可以显著提高小麦山农16的根长和山农22的株高,接种球毛壳ND35的山农16脯氨酸含量、可溶性糖含量、过氧化氢酶活性比对照组均显著提高,丙二醛含量比对照组降低9.0%,但差异不显著;山农22脯氨酸含量和过氧化氢酶活性比对照组显著提高,丙二醛含量和可溶性糖含量比对照组有所降低,但可溶性糖含量差异不显著;相对定量检测数据显示,接种球毛壳ND35后,两种小麦脱水素wzy2基因的表达量较对照组均能够显著提高。综合分析说明内生真菌球毛壳ND35可以促进冬小麦苗期根系和植株发育,小麦提前进入三叶期,增强小麦避旱性,同时提高小麦根系活力,增强小麦耐旱性;提高个体细胞内水分、糖分、脯氨酸含量,降低丙二醛的氧化性损伤,增强过氧化氢酶活性,从而提高两种冬小麦对干旱胁迫的耐受能力;球毛壳ND35促进小麦干旱诱导相关基因wzy2的表达量,进而提高抗旱相关蛋白的表达,从而提高两种冬小麦耐脱水性和对干旱胁迫的适应性。  相似文献   

19.
The effect of light on gene expression and hormonal status during the development of freezing tolerance was studied in winter wheat (Triticum aestivum var. Mv Emese) and in the spring wheat variety Nadro. Ten-day-old plants (3-leaf stage) were cold hardened at 5°C for 12 days under either normal (250 μmol m(-2) s(-1) ) or low (20 μmol m(-2) s(-1) ) light conditions. Comprehensive analysis was carried out to explore the background of frost tolerance and the differences between these wheat varieties. Global genome analysis was performed, enquiring about the details of the cold signaling pathways. The expression level of a large number of genes is affected by light, and this effect may differ in different wheat genotypes. Photosynthesis-related processes probably play a key role in the enhancement of freezing tolerance; however, there are several other genes whose induction is light-dependent, so either there is cross-talk between signaling of chloroplast originating and other protective mechanisms or there are other light sensors that transduce signals to the components responsible for stress tolerance. Changes in the level of both plant hormones (indole-3-acetic acid, cytokinins, nitric oxide and ethylene precursor 1-aminocyclopropane-1-carboxylic acid) and other stress-related protective substances (proline, phenolics) were investigated during the phases of the hardening period. Hormonal levels were also affected by light and their dynamics indicate that wheat plants try to keep growing during the cold-hardening period. The data from this experiment may provide a new insight into the cross talk between cold and light signaling in wheat.  相似文献   

20.
对布迪椰子的幼叶、成熟叶、叶柄和根在不同季节的干重热值、去灰分热值和灰分含量进行了研究,结果表明:干重热值四个季节的平均值为成熟叶(20.65kJg-1)>幼叶(19.84kJg-1)>根(19.55kJg-1)>叶柄(18.77kJg-1),秋季的干重热值明显高于其它三个季节的干重热值,冬季的干重热值最低,去灰分热值与干重热值的变化趋势基本相同。灰分含量四个季节的平均值为根(5.14%)>叶柄(4.33%)>幼叶(4.21%)>成熟叶(3.97%)。成熟叶的灰分含量一直维持在比较低的水平,而幼叶的在秋季明显下降,在冬季明显上升,幼叶灰分含量的季节变化趋势与成熟叶的相同,叶柄灰分含量在冬季明显低于根部。布迪椰子这种不同器官在不同季节的热值和灰分的变化规律显示其具有较强的耐寒适应性。  相似文献   

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