水分胁迫下小麦叶片蛋白质、淀粉和纤维素合成的示踪研究

利用光合１４ＣＯ２示踪技术,在－０．８ＭＰａＰＥＧ处理下,对等基因型不同抗旱性ＫＴＣ８６２１、ＮＤ７５３２和本地抗旱品种陕合６号小麦进行比较,其叶组织细胞质膜相对透性增加２７％－３２％,合成蛋白质放射性下降６２％－７０％;合成淀粉放射性下降必３％－６９％;合成纤维素放射性下降５９％－７１％。其中高抗旱的ＫＴＣ８６２１１大分子合成下降幅度小于等基因型低抗旱的ＮＤ７５３２和陕合６号,表明该品种叶体内大分子合成受水分胁迫的影响较小。正常水分条件下等基因型两品种叶酶溶物放射性及在ＰＥＧ干旱处理下的下降幅度均相近。陕合６号叶醇溶物放射性远远小于前两品种．     

玉米根系水流导度差异及其与解剖结构的关系

在人工气候室水培条件下,从单根水平研究了不同水分条件下玉米根系水流导度的基因型差异及解剖结构之间的关系.结果表明,抗旱性的杂交种户单四号具有水流导度上的杂种优势现象,不抗旱的父本803根系水流导度最低,3个品种根系水流导度大小为F₁代户单四号＞母本天四＞父本803;水分胁迫普遍降低了根系直径、导管直径和皮层厚度.同时,玉米品种根系的解剖结构和根系水流导度有关,正常水分条件下,根系导管直径与3个玉米品种的根系水流导度呈正相关,胁迫条件下则呈负相关.无论是在胁迫还是正常水分条件下,根系皮层厚度占根系直径的比例与根系水流导度都呈负相关,说明根系皮层是根系吸收水分的主要阻力部位.     

甘薯品种抗旱适应性综合评价的方法研究

在对水分胁迫下甘薯形态、生长势、生理生化和产量性状等指标与品种抗旱性进行相关分析的基础上,采用抗旱系数法、聚类分析法、隶属函数法对品种抗旱适应性予以综合评价.综合评价的结果,将15个供试甘薯品种按抗旱水平由弱到强划分为不抗（农大红、漳薯1号、8908-383）、低抗（宿芋1号、9318-58、渝苏303、89-1、95-411-153、西蒙1号）、中抗（92-111-107、渝薯34、南薯88、92-103-30）和高抗（Y3、潮薯1号）四级.上述几种关于甘薯品种抗旱适应性综合评价的方法具有较好的一致性.     

转AhNCED1基因拟南芥的形态特征和抗旱性研究

目的：探讨外源基因花生NCED1（AhNCED1）对拟南芥的形态特征和抗旱能力的影响。方法：观察转AhNCED1拟南芥的表型特征以及在干旱条件下的变化,利用扫描电镜观察植株叶上表面细胞和气孔大小。结果：与野生型相比,AhNCED1转基因植株矮壮,株型紧凑,分蘖和分枝数减少,幼苗根发育好。在干旱条件下转基因型植株叶大色绿,气孔开度减小,表皮细胞排列紧密。结论：转基因型植株在干旱条件下的表型特征与抗旱能力表明转基因拟南芥抗旱能力高于野生型。     

玉米抗旱品种的形态解剖学研究

在严格控水的防雨棚内,比较 抗旱筛选和省区试后表现抗旱高产的玉米新品种鲁玉１４号和对照掖单２号的殂态解剖结构,结果表明：玉米抗旱与不抗旱的差异并非品种的结构决定,而在抗旱性结构指标上存在差异。抗旱品种的叶片厚,气孔指数及气孔数／ｍｍ＾２大,侧根发生早、发生能力强可作为玉米抗旱育种与栽培的形态结构指标。     

沙棘的形态解剖学特性研究

1994～2002年先后在黄土高原半干旱区的安塞、吴旗县进行了沙棘形态解剖学特性试验研究。结果表明：沙棘叶具发达的表皮毛、较厚的角质层和发达的栅栏组织细胞,对大气干旱有强的适应性。根的周皮薄壁组织发达,细胞和细胞间隙较大,持水力强。沙棘由于具耐旱和节水型御旱的形态解剖和水分生理生态学特性,使沙棘耐旱、抗寒、耐水湿,在于旱、半干旱地区适应性强,并具有较高的生态、经济效益。本研究为沙棘在黄土高原半干旱区大面积荒山抗旱造林,经营管理提供了科学依据。     

胶孢镰刀菌产生串珠镰刀菌素的不稳定性

从陕北克山病病区分离到的两株串珠镰刀菌素产生菌株－胶孢镰刀菌陕－６号和２－１７号进行单孢分离,分别得到２３和１９个单孢分离株。这些单孢菌株可为两种培养型：一种形态上与原始菌株相似,产生串珠镰刀菌素,产色素,具有大、小分生孢子,转管八次产毒量有下降,另一种则不产串珠镰刀菌素和孢子,无色素,后者在二株菌的单孢分离菌中所占比例分别为６０．９％和１５．８％。由此可见,胶孢镰刀菌产毒稳定性受异核体和该菌单     

小青杨（populuspseud－simoni）生理生态特性的研究

在野外条件下,测定了小青杨树冠不同方向净光合速率和呼吸速率日进程呈双峰曲线形式,双峰出现在上午９时及下午１５时,低谷出现在１３时,即“午睡现象”,这与光照强度关系不大,而与环境因子有密切关系。小青杨树冠四个方向的光照强度都呈单峰曲线形式、温度也呈单峰曲线形式,但二者的峰值不同。树冠不同方向水分状况不同,饱和亏缺大者,水势较小,蒸腾强度也小。树冠不同方向,叶绿素含量不一,东面和北面叶绿含量较其他两面高,ａ／ｂ比值小于１。     

水分胁迫对小麦根质膜H~＋－ATPase活性与H~＋分泌的影响

在渗透势为－０．５和－１．０ＭＰａＰＥＧ处理下,不抗旱的郑引一号小麦根ＰＭＨ＋－ＡＴＰａｓｅ活性分别下降４５％和６５％,抗旱品种陕合六号则增加了１１％和１２％。小麦根组织Ｈ＋分泌与ＰＭＨ＋－ＡＴＰａｓｅ活性的变化趋势基本一致,即随着胁强增加,郑引一号Ｈ＋分泌下降,陕合六号Ｈ＋分泌是先升高后略降。Ｎａ３ＶＯ４和ＤＣＣＤ对Ｈ＋分泌有不同程度的抑制,品种之间没有明显的差异。外源电子受体Ｆｅ（ＣＮ）６３－的加入促进了小麦根Ｈ＋分泌,陕合六号增加２５％－３９％,郑引一号增加２１％－４５％。与此同时,Ｎａ３ＶＯ４没有表现出对Ｈ＋分泌的抑制作用。     

Adaptive plasticity in response to light and nutrient availability in the clonal plant Duchesnea indica

克隆植物蛇莓对光照强度和养分条件的适应性可塑性 表型可塑性可帮助植物缓冲环境压力并使其表型与当地环境相匹配,但目前仅少数性状的可塑性被广泛认为是适应性的。为充分理解可塑性的适应性意义,仍需进一步研究更多的植物功能性状及其环境因子。本研究将匍匐茎克隆植物蛇莓(Duchesnea indica)的21个基因型种植于不同的光照和养分条件下,并利用选择梯度分析检测了形态和生理可塑性对光照强度和养分有效性变化的适应性值。在遮荫条件下,蛇莓适合度(果实数、分株数和生物量)降低,节间缩短变细,成熟叶叶绿素含量降低,但叶柄长度、比叶面积、老叶叶绿素含量均增加。在低养分条件下,植株叶柄缩短,叶面积缩小变厚,叶绿素含量降低,但果实数量和根冠比增加。选择梯度分析表明,叶柄长度和老叶叶绿素含量对光照变化的可塑性是适应性的,老叶和成熟叶叶绿素含量对养分变化的可塑性也是适应性的。因此,不同性状的可塑性适应值取决于特定的生态背景。该研究的发现有助于理解克隆植物表型可塑性响应环境变化的适应性意义。     

Effect of Water Deficit Stress on Diffusive Resistance, Transpiration, and Spikelet Desiccation of Rice (Oryza sativa L.)

To understand the nature of panicle resistance to water loss,diffusive resistance, transpiration rate, and degree of tissuedesiccation were studied as affected by low tissue water potentialsand relative water contents (RWC) induced by water deficit stresses.A drought susceptible cultivar (IR20) and a moderately resistantcultivar (IRAT 13) were compared under moderate and severe waterdeficit stresses under greenhouse conditions. Irrigation waswithdrawn at flowering stage. During the 10-d stress period,changes in panicle and flag leaf transpiration and white headformation (desiccated) were monitored. Using cut panicles transpirationand white head formation at different RWC levels in 11 differentcultivars were also measured. In flag leaves, increased diffusiveresistance and leaf rolling reduced transpirational losses fromthe adaxial surfaces. Leaf resistance and rolling were linearlycorrelated with leaf water potentials. Resistance in paniclesincreased with progress decline in water potentials, but thechange was not as high as in leaves. Among test cultivars, diffusive resistance increased at thelate flowering stage but not at the early stage when panicleswere newly emerged. Increased water losses contributed to severespikelet desiccation and white heads. A few of the upland cultivarstested, such as Kinandang Patong, IRAT 140 and IRAT 13 conservedmore water and showed reduced water-deficit stress symptoms.Copyright1993, 1999 Academic Press Drought tolerance, drought susceptibility, rice panicles     

Drought effects on resource partition and conservation among leaf ontogenetic stages in epiphytic tank bromeliads

Studying the response to drought stress of keystone epiphytes such as tank bromeliads is essential to better understand their resistance capacity to future climate change. The objective was to test whether there is any variation in the carbon, water and nutrient status among different leaf ontogenetic stages in a bromeliad rosette subjected to a gradient of drought stress. We used a semi-controlled experiment consisting in a gradient of water shortage in Aechmea aquilega and Lutheria splendens. For each bromeliad and drought treatment, three leaves were collected based on their position in the rosette and several functional traits related to water and nutrient status, and carbon metabolism were measured. We found that water status traits (relative water content, leaf succulence, osmotic and midday water potentials) and carbon metabolism traits (carbon assimilation, maximum quantum yield of photosystem II, chlorophyll and starch contents) decreased with increasing drought stress, while leaf soluble sugars and carbon, nitrogen and phosphorus contents remained unchanged. The different leaf ontogenetic stages showed only marginal variations when subjected to a gradient of drought. Resources were not reallocated between different leaf ontogenetic stages but we found a reallocation of soluble sugars from leaf starch reserves to the root system. Both species were capable of metabolic and physiological adjustments in response to drought. Overall, this study advances our understanding of the resistance of bromeliads faced with increasing drought stress and paves the way for in-depth reflection on their strategies to cope with water shortage.     

Leaf Water Diffusion Resistance in Clonal Tea (Camellia sinensis L.): Effects of Water Stress, Leaf Age and Clones

Leaf diffusion resistance was influenced by leaf age in well-wateredand water-stressed clonal tea plants. In well-watered plantsand in two of the three clones studied, young leaves showeda significantly lower diffusion resistance than old leaves.In water-stressed plants young leaves always exhibited a higherdiffusion resistance than old leaves. The highest diffusionresistance, irrespective of leaf age and water stress, occurredin clone DN which is known to be the most drought tolerant ofthe three clones studied, suggesting that drought tolerancein clone DN is caused, at least in part, by a stomatal regulationmechanism. Water release characteristic curves for the threeclones indicated differences in the water content-water potentialrelationship between young and old leaves as well as betweenclones. The drought tolerant clones had a higher relative watercontent for a given water potential compared with the drought-susceptibleclone. Camellia sinensis L., tea, diffussion resistance, water stress     

晋西黄土丘陵区若干树种水分生理及抗旱性量化研究

1996年林木生长季节(5~10月)野外条件下测定了12个树种的P-V曲线水分参数。研究了水分参数的季节变化及与林木抗旱性的关系。提出树种在水分胁迫条件下以水分参数Ψ_i^sat和Ψ_i^tlp所定义的渗透调节能力。并研究了树种的这种渗透调节能力的季节变化规律及与环境因素的关系。应用数量分析的方法对林木的抗旱性予以综合评价。     

Improving drought resistance in small-grained cereals: A case study, progress and prospects

Drought is a serious problem in many parts of the world where wheat, barley and other small-grained cereals are part of the staple diets. Even in parts of South-eastern Europe, seasonal rainfall for winter cereals has been falling gradually for many years. Thus, since 1981 across three sites in Yugoslavia (Novi Sad, Kragujevac and Zajear), rainfall fell from a mean of 511 mm for October to July in 1981--1982 to about 453 mm during the same period for the 1995--1996 season. Nevertheless, average wheat yields for new varieties in Yugoslav Commission trials during this period have shown a steady increase from 7.6 to 8.8 t ha^–1. This is due to increasing the yield potential of the new varieties, even in trials giving low average yields, caused largely by drought. Thus, breeders in Yugoslavia are succeeding in improving drought resistance in new wheat varieties. However, future progress in improving drought resistance may be helped by focusing on specific traits which will help to improve either crop water use, water-use efficiency or harvest index. Thus, for example, rapid early leaf area development not only improves subsequent crop growth rates, but increases competition with weeds for water and nutrients. The rate of leaf area development is closely associated with embryo size, so selection for large embryo size should improve early growth rates. Osmotic adjustment in wheat in response to drought appears to be important for maintaining yields, and selection for high osmotic adjustment has improved drought yields. Carbon 13 discrimination () is an integral measure of plant water-use efficiency. Selecting for low has also resulted in increased yield under drought conditions. Other constitutive and induced traits, such as phenology, leaf xeromorphy, excised-leaf water loss, rooting behaviour, senescence and stored assimilates are also discussed in relation to improving yields in small-grain crops. Opportunities for marker-assisted selection are also considered. Incorporating specific drought resistance traits in breeding programmes should facilitate more rapid improvement in the drought resistance of wheat and other small-grained cereals.     

Comparative physiological and metabolomic responses of four <Emphasis Type="Italic">Brachypodium distachyon</Emphasis> varieties contrasting in drought stress resistance

Brachypodium distachyon (Brachypodium) is not only a monocot grass species, but also a promising model organism of crop research. In this study, the drought resistance of four Brachypodium varieties was identified including drought stress-tolerant Bd1-1 and Bd21, drought stress-susceptible Bd3-1 and Bd18-1. Physiological assay showed that drought-tolerant varieties (Bd1-1 and Bd21) were more effective in maintenance of leaf water content, activation of catalase and peroxidase activities and accumulation of reduced glutathione, resulting in alleviated cell damage and lower reactive oxygen species level than drought-susceptible varieties (Bd3-1 and Bd18-1) in response to drought stress. In addition, 54 primary metabolites were differentially regulated among Brachypodium varieties and after drought stress treatment, indicating the complexity of Brachypodium response to drought stress. We also identified several commonly regulated metabolites especially some compatible solutes including proline and soluble sugars, which exhibited higher concentrations in the drought-tolerant varieties. Taken together, this study suggested that natural variation of Brachypodium varieties in response to drought stress might be connected with higher leaf water, enhanced accumulation of osmolyte and more effective antioxidant system, as well as the modulation of metabolic profiles under drought stress conditions.     

Effect of drought on ear and flag leaf photosynthesis of two wheat cultivars differing in drought resistance

We investigated net photosynthetic rate (P_N) of ear and two uppermost (flag and penultimate) leaves of wheat cultivars Hongmangmai (drought resistant) and Haruhikari (drought sensitive) during post-anthesis under irrigated and non-irrigated field conditions. The P_Nof ear and flag leaf were significantly higher and less affected by drought in Hongmangmai than in Haruhikari. The rate of reduction in stomatal conductance (g_s) was similar for the two cultivars, but intercellular CO₂concentration (C_i) in the flag leaf of Hongmangmai was lower than that of Haruhikari in non-irrigated treatment. No differences were observed in leaf water potential (ψ₁) and osmotic adjustment of the flag leaf of the cultivars. These results imply that differences in photosynthetic inhibition on the flag leaf at low leaf ψ₁between the cultivars were primarily due to non-stomatal effects. Hence the main physiological factor associated with yield stability of Hongmangmai under drought stress may be attributed to the capacity for chloroplast activity in the flag leaf, which apparently allows sustained P_Nof flag leaf during grain filling under drought stress. The higher P_Nof ear in Hongmangmai under drought could also be related to its drought resistance.     

无机营养对春小麦抗旱适应性的影响

本文研究了无机营养对春小麦一些抗旱适应性的影响,主要包括:渗透调节的大小和变化过程、可溶性糖的积累、脯氨酸的积累、叶片导度的变化、离体叶片的失水速率、叶面积和耗水量的变化、根系生长和根/植冠值,并且分析了各个处理植株的水分利用效率(WUE)和产量的变异。认为,在干旱条件下,无机营养对于春小麦不同器官、不同生理功能,并不都具有一致的作用。有的利于提高植株的抗旱性,有的可以改变一些适应性产生的时间和发展过程,有的则不利于植株的抗旱性。通过综合分析,提出旱地施肥使作物增产的主要原因是,营养元素满足了作物生长所需,促进了根系发育,利于吸收水分、维持水分平衡和正常生理功能,但对作物自身的耐旱性并没有产生显著影响。     

Effect of low salinity on ion accumulation, gas exchange and postharvest drought resistance and habit of Coriandrum sativum L.

Aims

Drought resistance of crops is one of the great challenges for the world’s agricultural systems. Although the concept of ‘drought hardening’ has been known for many years, very little has been done on pre-harvest treatment that can help leafy vegetable crops resist drought stress on a retailer’s shelf. Our hypothesis was that for pot-grown vegetables a saline treatment could be found that would reduce transpiration pre- and post-harvest, but not harvestable yield.

Methods

Coriander (Coriandrum sativum L.) was used as a model plant; several accessions (k-4, k-43, k-52, k-60 and k-62) from N.I. Vavilov Research Institute of Plant Industry, Russia and two commercial cultivars—Kashmir and Americanum—were studied. Plant growth, weight, transpiration, net CO2 assimilation, respiration, wilting, apparent petioles rigidity, leaf sodium content, elemental analysis and osmotic potential were assessed.

Results

We found that minor salinity (12.5?mM Na2SO4) triggered both drought and salt resistance mechanisms, which regulate appearance and shelf-life of pot-grown coriander.

Conclusion

We found that the drought avoidance mechanisms (i.e. decreased transpiration and increased water use efficiency) and salt tolerance mechanisms induced by pre-harvest treatment could significantly postpone wilting and improve post-harvest habit of a leafy vegetable crop.     

花生抗旱性鉴定指标的筛选与评价

为确定鉴定花生(Arachis hypogaea)品种(系)抗旱性指标体系, 综合评价花生品种(系)的抗旱性, 在人工控水条件下, 通过盆栽试验, 测定了29个花生品种(系)苗期和花针期的株高、分枝数、生物累积量、叶片含水量和光合色素含量等与抗旱性有关的13个表观形态性状和生理性状的指标, 采用抗旱系数法和隶属函数值法, 对各指标性状进行了水分胁迫下的抗性评价和鉴定。结果表明, 29个花生品种(系)可划分为抗旱性较强、中等、较弱和不抗旱4类, 其中‘唐科8号’、‘冀花2号’、‘大唐油’、‘花育25号’、‘花育17号’、‘鲁花14号’、‘丰花1号’ 7个品种(系)具有较强的抗旱能力; 苗期同一品种(系)的主茎高、分枝数和生物累积量等形态指标和光合色素等生理指标的隶属函数值均有较大差别, 苗期各指标隶属函数值与品种(系)抗旱性无显著相关关系, 苗期单一形态指标不能作为鉴定品种(系)抗旱性的指标; 但苗期抗旱性综合评价值(D)与抗旱系数间存在显著相关关系, D的大小可作为抗旱性的鉴定指标。花针期形态指标和生理指标D值间, 以及各类指标D值与抗旱系数间均存在显著或极显著的相关关系, 此期植株形态指标、生理指标隶属函数值以及综合D值均可作为鉴定品种(系)抗旱性的指标。