植物耐寒机理与耐寒植物新品种培育

低温灾害是普遍存在的对植物造成严重伤害的自然灾害,研究植物耐寒的分子机理并积极培育耐寒植物新品种对农业等生产活动具有重要意义.主要介绍植物抵御低温时的生理生化变化和关键基因,以及抗冻蛋白在耐寒植物新品种培育中的应用,并探讨植物耐寒育种的发展趋势.     

Thermal acclimation and the dynamic response of plant respiration to temperature

Temperature-mediated changes in plant respiration (R) are now accepted as an important component of the biosphere's response to global climate change. Here we discuss the underlying mechanisms responsible for the dynamic response of plant respiration to short and long-term temperature changes. The Q(10) is often assumed to be 2.0 (i.e. R doubles per 10 degrees C rise in temperature); however, the Q(10) is not constant (e.g. it declines near-linearly with increasing temperature). The temperature dependence of Q(10) is linked to shifts in the control exerted by maximum enzyme activity at low temperature and substrate limitations at high temperature. In the long term, acclimation of R to temperature is common, in effect reducing the temperature sensitivity of R to changes in thermal environment, with the temperature during plant development setting the maximal thermal acclimation of R.     

提高植物抗寒性的机理研究进展

低温胁迫是世界范围内影响植物产量和品质的主要非生物胁迫.植物抗寒生理生态研究是比较活跃和发展很快的领域.文章综述了提高植物抗寒性机理的研究进展.大量科学研究和生产实践表明,气象因素与植物自身因素是影响植物抗寒性的关键因素,前者主要是温度、光周期和水分,后者主要是植物的遗传学基础、生长时期、发育水平以及低温胁迫下细胞的抗氧化能力.保证植物抗寒基因充分表达对提高植物抗寒性有重要意义.植物抗寒性的遗传机制与调控主要通过5条路径实现:丰富多样的植物低温诱导蛋白,低温转录因子DREB/CBF可同时调控多个植物低温诱导基因的表达,DREB/CBF与辅助因子相互作用调控下游基因表达,Ca2+、ABA及蛋白质磷酸化上游调控低温诱导基因表达,以及不饱和脂肪酸酶基因的表达.基因工程改良植物抗寒性已获重要进展,但距产业化尚有许多开创性的工作要做,目前主要通过导入抗寒调控基因和抗寒功能基因而实现,后者主要是导入抗渗透胁迫相关基因、抗冻蛋白基因、脂肪酸去饱和代谢关键酶基因、SOD等抗氧化系统的基因以及与植物激素调节有关的基因.农林技术对提高植物抗寒性有重大实用价值,其中的不少技术蕴涵着深刻的科学机理,重点评述了抗寒育种、抗砧嫁接、抗寒锻炼、水肥耦合及化学诱导五大技术提高植物抗寒性的作用机理.展望了提高植物抗寒性的研究.     

Temperature drop, dry matter accumulation and cold resistance of young cucumber plants

The study aimed to provide information on the involvement of plant cold resistance in a whole cucumber (Cucumis sativus L.) plant response to temperature drop treatments. The main objective was to explain the effects of a temperature drop on dry matter production and plant morphogenesis. The experimental design included temperature drops to 12°C for 0, 1, 2, 4 and 6 hours at the beginning, in the middle and at the end of the night. The overall average temperature for all treatments was 20°C. A 2-hour temperature drop resulted in the most significant reduction in plant dry weight and leaf petiole length, but the highest degree of cold resistance. With the extension of a temperature drop duration to 4--6 hours, dry matter production was similar to that in the control plants, leaf petiole length increased, but not up to the control level and cold resistance was reduced, but was still higher compared to that of the control plants. Changes in dry matter production, leaf petiole length and cold resistance, depending on the duration of the temperature drop, were interrelated and their patterns varied little with the timing (position effect) of the temperature drop. It is concluded that plant cold resistance mechanisms play an important role in a whole plant response to temperature drop treatments. Thus, plant response to temperature drop treatments can be considered as a response to stress.     

冠层温度在水稻抗旱性基因型筛选中的应用及其测定技术

本文综述了冠层温度在水稻抗旱性基因型筛选中的应用及其研究进展,并介绍了利用红外测温仪测定冠层温度的方法。作物不同基因型之间存在冠层温度的差异,并且从理论上讲,冠层温度与作物水分利用相关,因而把冠层温度作于作物基因型筛选是有价值而且是可行的。利用红外测温仪测定水稻冠层温度是一顶非接触性测温法,为水稻抗旱性基因型的筛选提供了一种简便、快速、非破坏性的技术。     

The magnitude of the temperature-driven contribution to within-plant transport

Abstract The contribution from temperature gradients within a plant to convective transport is calculated. Its magnitude depends primarily on the temperature differences in the plant and the radius of the conducting elements; the other quantities affecting it are well-established physical constants. Assuming a temperature difference in the plant of 1 K and a conductive element radius of 10^?4 m, the speed of convective flow is 0.5 cm h^?1 and this is independent of distance.     

增温与放牧对矮嵩草草甸4种植物气孔密度和气孔长度的影响

设计增温和放牧耦合试验研究增温和放牧对高寒植物气孔密度和气孔长度的影响,选择矮嵩草（Kobresia humilis）、高山唐松草（Thalictrum aplinum）、垂穗披碱草（Elymus nutans Griseb.）和麻花艽（Gentiana straminea）作为试验材料。结果表明增温与放牧分别影响这4个物种气孔形态参数的不同方面：温度使4个物种气孔长度一致性地变小（P<005）,放牧使气孔密度和潜在气孔导度指数（PCI）一致性地上升（P<0.05）。气孔密度对增温的响应趋势和气孔长度对放牧的响应趋势在不同物种间存在差异。气孔长度减小可能是对增温引起的水分胁迫的响应,气孔密度和潜在气孔导度指数上升反映出四种植物在本研究相应的放牧强度下存在补偿性生长的可能。     

植物应答低温胁迫机制的研究进展

低温是植物生长过程中遇到的主要环境胁迫因子之一,而植物响应低温胁迫是一个多因素协同作用的过程,涉及到复杂的基因表达调控网络。尤其是低温下植物体内生理生化、细胞骨架结构及基因表达调控等方面的改变及相关机制,一直受到研究者的普遍关注。该文主要从细胞学及分子生物学等角度入手,将低温胁迫下植物对低温的响应及可能机制进行综述,着重对植物通过细胞内部细胞器结构与功能的改变来抵御或适应低温,尤其对细胞骨架,以及低温信号转导受体及中间体、下游胁迫相关基因的表达及其在细胞内部的调控及应答机制等方面的作用进行探讨,为耐低温植物新品种的培育及农业生产实践提供理论指导。     

Temperature-regulation of plant architecture

As sessile organisms, plants have evolved great plasticity to adapt to their surrounding environment. Temperature signals regulate the timing of multiple developmental processes and have dramatic effects on plant architecture and biomass. The modulation of plant architecture by temperature is of increasing relevance with regard to crop productivity and global climate change. Unlike many other organisms, the mechanisms through which plants sense changes in ambient temperature remain elusive. Multiple studies have identified crosstalk between ambient temperature sensing, light signaling, cold acclimation and pathogen response pathways. The regulation of plant architecture by temperature appears to involve the complex integration of multiple hormone signaling networks. Gibberellin (GA), Salicylic Acid (SA) and cytokinin have been implicated in the regulation of plant growth during chilling, whilst a predominant role for auxin is observed at high temperatures. This mini-review summarizes current knowledge of plant growth regulation by temperature and crosstalk with other abiotic and biotic stress signaling pathways.Key words: temperature, architecture, elongation, growth, hormone, auxin, gibberellin, salicylic acid, biomass     

Developmental patterns of a large set of barley (Hordeum vulgare) cultivars in response to ambient temperature

Ambient temperature plays an important role in plant development. In cereals, little is known about the exact effects of ambient temperature in the range between it being a vernalising agent and an abiotic stress factor; thus the genetic determinants involved in the registering and response to ambient temperature, and their natural variation has not been dissected either. Principally, we wished to establish the level of natural variation in response to ambient temperature in barley via studying plant phenological development. The responses to temperature of 168 barley genotypes of different provenances and seasonal growth habit groups were observed in controlled environments. The effects of four temperature regimes (13°C, 16.5°C, 18°C and 23°C) on the duration of plant phenophases were examined. The plant development was characterised in a series of consecutive phenophases that span the plant life cycle from germination through flowering to attainment of maximum plant height. Ambient temperature affected significantly plant development, with substantial variation in responses among the genotypes. Six major types of responses were identified, which depended strongly on seasonal growth habit, with only a small degree of overlap. Although the differences in the timing of development among clusters were significant under each temperature regime, the 23°C treatment resulted in the largest diversity of responses, with significant changes in the ranking of the six clusters compared to other treatments. Two clusters showed particularly unusual responses to 23°C: the development of one winter barley cluster was extremely accelerated by the 23°C treatment, whereas the development of one spring barley cluster was significantly delayed. Ambient temperature assumes importance as a regulatory cue in the intricate and complex temporal and spatial regulation network of plant development in cereals and acts mostly through its regulatory effect on certain developmental phases such as the onset and duration of the intensive stem elongation.     

湛江电厂对周围水域生态的影响分析

调查和实测资料分析结果表明,湛江电厂对麻斜海水生生态的影响主要局限于排水口附近温升在2℃以上的狭小区域,电厂温排水引起的温升对浮游生物和鱼类的影响表现为夏季在强增温区内使生物物种和数量减少,而对整个渔业生产和海洋微生物的生长不会产生明显影响,但电厂取水对麻斜海大型水生生物和鱼类会造成冲撞危害。     

寄主植物对甜菜夜蛾三龄幼虫抗寒力的影响

寄主植物是影响昆虫抗寒性的主要因子之一。研究了不同温度下甜菜夜蛾Spodoptera exigua(Hübner)3龄幼虫取食小白菜、甘蓝、葱和菠菜后,对过冷却能力和体内冷冻保护剂的影响。结果表明,寄主植物对甜菜夜蛾3龄幼虫的过冷却能力有显著性影响,其中以取食甘蓝的幼虫过冷却点最低。温度和寄主植物对其过冷却点、结冰点和虫体含水量有明显的交互作用。寄主植物对其体内的海藻糖含量有显著性影响,而对甘油和糖原含量没有显著性影响。温度和寄主植物仅对海藻糖含量有显著的交互作用。随着温度的升高,取食不同寄主的幼虫体内海藻糖和糖原含量的变化趋势完全相反,认为海藻糖是由糖原转化而来。研究结果提示冬季合适的寄主植物有利于甜菜夜蛾低龄幼虫越冬。     

The influence of floating vascular plants on the diurnal fluctuations of temperature near the water surface in early spring

On clear days the temperature in a mat of floating Lemnaceae was 4° to 11° above that of the surface of the open water. The temperature of the environment 2 cm above or below the plant surface closely followed the surface temperature's quick response to changes in net radiation. The plant surface reflects more enery and transmits less than the open water, therefore there is less fluctuation in temperature in the water 10 cm and more below the floating plant surface. This results in a diurnal thermal stratification. At the surface of the open water changes in temperature tended to be smaller and slower, related to the air temperature; and, with wind disturbance, the water profile maintained relatively homogeneous temperatures.     

Optimal temperature drop for the growth and development of young cucumber plants

The thermomorphological responses of young cucumber plants to a temperature drop lasting 2, 4 and 6 hours applied at the beginning, in the middle and at the end of the night were examined. Plant height, leaf petiole length and plant dry weight were measured and, based on the experimental data, the regression dependences of growth variables on the temperature drop were fitted. A method to determine the optimal temperature drop (the duration and time of exposure) which results in shortened plant height and leaf petiole length without a decrease in plant dry weight is proposed.     

How the Plant Temperature Links to the Air Temperature in the Desert Plant Artemisia ordosica

Plant temperature (Tp) is an important indicator of plant health. To determine the dynamics of plant temperature and self-cooling ability of the plant, we measured Tp in Artemisia ordosica in July, in the Mu Us Desert of Northwest China. Related factors were also monitored to investigate their effects on Tp, including environmental factors, such as air temperature (Ta), relative humidity, wind speed; and physiological factors, such as leaf water potential, sap flow, and water content. The results indicate that: 1) Tp generally changes in conjunction with Ta mainly, and varies with height and among the plant organs. Tp in the young branches is most constant, while it is the most sensitive in the leaves. 2) Correlations between Tp and environmental factors show that Tp is affected mainly by Ta. 3) The self-cooling ability of the plant was effective by midday, with Tp being lower than Ta. 4) Increasing sap flow and leaf water potential showed that transpiration formed part of the mechanism that supported self-cooling. Increased in water conductance and specific heat at midday may be additional factors that contribute to plant cooling ability. Therefore, our results confirmed plant self-cooling ability. The response to high temperatures is regulated by both transpiration speed and an increase in stem water conductance. This study provides quantitative data for plant management in terms of temperature control. Moreover, our findings will assist species selection with taking plant temperature as an index.     

Management of plant health risks associated with processing of plant-based wastes: A review

The rise in international trade of plants and plant products has increased the risk of introduction and spread of plant pathogens and pests. In addition, new risks are arising from the implementation of more environmentally friendly methods of biodegradable waste disposal, such as composting and anaerobic digestion. As these disposal methods do not involve sterilisation, there is good evidence that certain plant pathogens and pests can survive these processes. The temperature/time profile of the disposal process is the most significant and easily defined factor in controlling plant pathogens and pests. In this review, the current evidence for temperature/time effects on plant pathogens and pests is summarised. The advantages and disadvantages of direct and indirect process validation for the verification of composting processes, to determine their efficacy in destroying plant pathogens and pests in biowaste, are discussed. The availability of detection technology and its appropriateness for assessing the survival of quarantine organisms is also reviewed.     

植物环境响应启动子的诱导元件及转录因子

光、温度、水分等环境因素影响植物的生长发育,植物可以通过启动子中顺式作用元件与转录因子的相互协调作用,对这些信号产生响应,调控基因表达。本文综述了光、温度、水分诱导表达启动子中的顺式作用元件及相关转录因子研究的最新进展,从分子水平上探讨了环境因子诱导的基因表达调控,对研究植物适应环境的机制具有一定的意义。     

高寒草甸15种植物种子发芽的比较研究

对高寒草甸 15种植物种子的发芽进行了比较实验研究。结果显示 ,冷湿层化、温度变幅及光照条件能够提高或者降低多数高寒草甸植物种子发芽率。其中 ,13种植物对层化、11种对光照条件、14种对温度变幅处理有显著性响应。 15种植物中 ,有14种对单一因子或因子组合有反应 ,仅藏嵩草种子发芽对设定的因子或因子组合没有响应。根据不同植物种子对不同处理及其组合的发芽反应可将植物种子划分为不同的反应类型 ,通过对种子进行冷湿层化处理 ,可以部分或者全部地替代某些植物种子发芽对光、温需求。探明植物种子在特定环境因子组合条件下的发芽表现 ,对通过种子恢复退化草甸是至关重要的。