盐分和水分胁迫对菊芋幼苗离子吸收及叶片酶活性的影响

采用砂培试验,用不同浓度的NaCl和等渗PEG6000(聚乙二醇6000,渗透势约为-0．44MPa)处理生长20d的菊芋幼苗,3d后分别测定其根、茎、叶中的Na^ 、K^ 、Cl^-含量以及叶片SOD、POD活性。结果表明,在NaCl和PEG胁迫下,根、茎、叶的Na^ 、Cl^-含量不断升高,而K^ 含量保持稳定。其中,茎中Na^ 含量高于根和叶。NaCl胁迫下,根、茎、叶的SX、Na值随胁迫强度的增加而递增,茎中SK、Na值小于根和叶。随着NaCl胁迫强度的增加,菊芋幼苗叶片的SOD和POD活性先上升后下降;PEG处理下,SOD活性分别高于对照和等渗NaCl处理31．1％和27．1％;而POD活性却分别低于对照和等渗NaCl处理26．0％和36．1％。     

盐分和干旱对沙枣幼苗生理特性的影响

以沙枣(Elaeagnus angustifolia L.)幼苗为实验材料,分别对其进行轻度干旱(土壤含水量7%—9%)、重度干旱(土壤含水量3%—5%)、100 mmol/L NaCl以及100 mmol/L NaCl处理下不同程度的盐旱共胁迫处理,处理2周后测其生理指标,包括生长指标、光合指标、渗透调节指标以及复水后生长指标,研究盐旱共胁迫对沙枣幼苗生理特性的影响。结果表明:和对照相比,轻度干旱对沙枣幼苗的生物量没有显著影响,重度干旱处理明显降低了沙枣的生物量,无论是轻度干旱还是重度干旱,都显著降低了沙枣幼苗的净光合速率、K~+含量,显著增加了Na~+含量、脯氨酸含量、可溶性糖含量、有机酸含量、总酚和类黄酮含量;和对照相比,100 mmol/L NaCl处理显著降低了沙枣幼苗的生物量、净光合速率和K~+含量,显著增加了Na~+含量、脯氨酸含量、可溶性糖含量、有机酸含量、总酚和类黄酮含量;和盐处理相比,轻度干旱和盐分共胁迫对沙枣幼苗的各项指标没有显著差异,而重度干旱和盐分共胁迫明显降低了沙枣幼苗的生物量、净光合速率;复水一周后,只有轻度干旱可以回复到对照水平。以上结果表明,盐分和干旱处理明显抑制了沙枣幼苗的生长,轻度干旱和盐分共胁迫条件下,沙枣幼苗表现出一定的交叉适应现象,而重度干旱却加重了盐害。     

不同形态氮素配比对盐胁迫下菊芋幼苗生理的影响

采用砂培方法研究了不同铵硝配比(NH4+/NO3-分别为4/1、1/1、1/4)的氮素营养和盐分胁迫耦合作用下菊芋幼苗的光合作用和离子吸收运输.结果表明:低浓度的盐胁迫对植物生长的抑制作用不大,而高浓度的盐胁迫却能明显抑制菊芋幼苗生物量的积累,在同一盐浓度下,提高硝态氮比例能够缓解盐胁迫对菊芋幼苗生长的抑制,促进菊芋幼苗鲜重和干重的增加;随着盐浓度的增加,菊芋幼苗地上部和地下部的Na+含量显著增加,而K+、Ca2+含量较对照显著降低,提高硝态氮比例有利于菊芋幼苗对K+和Ca2+的吸收和向上运输,从而维持地上部较高的K+/Na+和Ca2+/Na+;在3种铵硝比的氮素营养处理下,随着盐浓度的增加,菊芋幼苗叶片叶绿素含量、净光合速率、蒸腾速率、气孔导度和水分利用效率较对照均呈显著下降的趋势,细胞间隙CO2浓度则显著增加,提高硝态氮比例可显著提高盐胁迫下菊芋幼苗的叶绿素含量、净光合速率、蒸腾速率、气孔导度和水分利用效率,同时也能显著降低胞间CO2浓度,其中以铵硝比为1/4的氮素营养供应对盐胁迫的缓解作用相对较好,在100 mmol·L-1NaCl处理下其叶片叶绿素含量、净光合速率、蒸腾速率、气孔导度和水分利用效率分别是铵硝比为4/1的氮素营养处理值的1.63、1.57、1.39、1.37、1.2倍,而胞间CO2浓度则减少了17%.因此相对于铵态氮来说,硝态氮比例的增加有利于维持盐胁迫下菊芋幼苗体内矿质营养元素含量平衡,促进盐胁迫下菊芋光合功能的改善,增强菊芋对盐胁迫的抗性.     

植物反射光谱对水分生理变化响应的研究进展

实时、无损伤地探测植物的水分及生理变化是高光谱遥感的深层次应用。由水分胁迫引发的植物一系列反射光谱响应体现了碳-氮-水耦合作用的结果。以往的研究大多集中于单一因素的响应, 而忽略了多因素交互作用。该文综述和分析了植物水分状况变化引起的直接和间接光谱响应机制, 包括植物水分含量、色素、养分状况、光合作用和叶绿素荧光指标的光谱响应及其内在的关联, 探讨了反射光谱在探测植物水分生理活动应用中的主要方法与最新技术, 并指出碳-氮-水多指标、多时空尺度的综合分析对于估测植被生产力及其对气候变化的响应具有重要意义。     

盐分和水分胁迫对两种盐生植物盐爪爪和盐穗木种子萌发的影响

采用不同浓度NaCl和等渗PEG(分子量为6000)处理2种盐生植物种子(盐爪爪Kalidiumfoliatum、盐穗木Halostachys caspica)。结果表明,(1)NaCl和等渗PEG对种子的萌发均产生抑制作用,且PEG的抑制程度大于等渗NaCl,说明渗透胁迫是影响盐生植物种子萌发的主要因素;(2)盐胁迫和水分胁迫对盐生植物种子的萌发具有明显的抑制作用,降低了种子的萌发率,推迟了种子的初始萌发时间、延长了种子的萌发时间;(3)根据2种盐生植物种子萌发耐盐性比较,两种盐生植物均具有较强的耐盐性,在0~300 mmol.L-1NaCl盐溶液范围内,盐穗木种子相对萌发率达到95%以上,盐爪爪达到80%以上,说明盐穗木比盐爪爪具有更强的耐盐性。盐穗木种子耐盐适宜值为332.5 mmol.L-1,临界值为540 mmo.lL-1,极限值为749 mmo.lL-1;盐爪爪种子耐盐适宜值为246.5 mmol.L-1,临界值为391.8 mmo.lL-1,极限值为537 mmol.L-1;(4)低浓度的NaCl溶液对种子萌发的幼苗生长起着促进作用。在100 mmo.lL-1NaCl处理时,两种盐生植物幼苗的胚...     

等渗的盐分和水分胁迫对芦荟幼苗生长和离子分布的效应

 研究了等渗透势（-0.44、-0.88 MPa）NaCl和PEG 6000处理对六叶龄芦荟(Aloe vera)幼苗叶片生长速率、干物质积累、电解质渗漏和离子吸收、分配的效应。结果表明: -0.44、-0.88 MPa NaCl和PEG处理10 d均明显抑制芦荟幼苗叶片伸长生长,植株干物质积累速率显著降低, 叶片含水量降低,叶片细胞电解质渗漏率上升。NaCl对芦荟幼苗生长的抑制作用显著大于PEG处理的。不同器官离子含量、根系和叶片横切面X-射线微区分析结果表明, NaCl胁迫导致芦荟体内Na+、Cl－含量显著上升,根中增幅明显高于叶片,其中Cl－尤为显著。NaCl胁迫严重抑制芦荟对K+ 和Ca2+ 的吸收及其向叶片的运输,根、叶K+/Na+、Ca2+/Na+ 比率显著下降,而PEG胁迫对离子平衡的干扰较轻,是芦荟对水分胁迫的适应能力高于盐胁迫的主要原因之一。但芦荟对 -0.44～-0.88 MPa NaCl胁迫仍有一定的适应能力,主要原因是：1) 根系对离子的选择性吸收和运输较强,并随着盐胁迫强度增加其选择性增强; 2) 芦荟叶片中的盐分在贮水组织中显著积累,明显高于其它组织细胞。同时,芦荟是CAM（景天酸代谢）途径植物,蒸腾极小,盐分随蒸腾流进入地上部的机会小。     

盐分和水分胁迫对盐生植物灰绿藜种子萌发的影响

研究了不同浓度的NaCl和复合盐及等渗溶液(PEG-6000)处理下盐生植物灰绿藜(Chenopodium glaucum L.)种子的萌发状况.结果表明:灰绿藜种子的萌发率与处理溶液的浓度或渗透势之间有显著的负相关关系;在低浓度盐溶液(2.9 g*L-1)中灰绿藜种子的萌发率高于对照(蒸馏水);NaCl溶液对灰绿藜种子萌发的抑制作用大于复合盐溶液.渗透势为-0.2和-0.5 mPa 时,PEG-6000溶液对灰绿藜种子萌发的抑制作用小于等渗NaCl溶液,而在较高渗透势溶液中则正好相反.用渗透势≤-1.8 mPa 的PEG-6000溶液及所有浓度的NaCl和复合盐溶液处理的种子复水后相对萌发率都达到了90%以上,说明一定程度的盐分和水分胁迫对灰绿藜种子萌发潜力并没有很大的影响,并且萌发恢复率随处理盐浓度或PEG-6000溶液渗透势(≤-1.4 mPa)的增加而增加.     

盐生植物碱地肤对盐碱胁迫的生理响应特点

以天然盐生植物碱地肤(Kochia sieversiana)为材料,采用人工生态模拟方法对其施加0~480mmol/L的盐胁迫(摩尔比1∶1的NaCl和Na2SO4)和碱胁迫(摩尔比1∶1的NaHCO3和Na2CO3),测定了盐碱胁迫下的相对生长率(RGR)、叶绿素含量及丙二醛含量.结果表明:低浓度的盐胁迫(80mmol/L)对碱地肤的生长具有刺激作用,其在高达480mmol/L的盐胁迫或400mmol/L的碱胁迫下仍能存活并维持一定的生长,具有强抗盐性和强抗碱性;在相同盐浓度下,碱地肤受碱胁迫的伤害强度和对碱胁迫所做出的胁变反应均大于对盐胁迫.可见,碱地肤的抗盐性强于抗碱性,受碱胁迫的伤害大于盐胁迫,维持高含水量可能是碱地肤适应高强度盐碱胁迫的重要特性.     

藜科盐生植物的形态特征与耐盐分子机理研究进展

在非生物环境胁迫因子中,盐胁迫是造成农作物减产的主要因素之一.从藜科植物耐盐的形态生理学机制和分子生物学角度入手,讨论了藜科植物耐盐基因工程的新进展,探讨藜科盐生植物的盐胁迫机理,为利用基因工程手段培育耐盐植物奠定基础.     

植物耐盐性机理研究进展

在盐胁迫下环境中某些植物会在发生一些变化。从生理学、生物化学、盐胁迫分子学机制的角度对植物对盐胁迫的反应研究进行了回顾,并提供了一些目前知识水平上能增加植物盐耐性的方法。解释了在盐胁迫下植物的离子吸收、相溶性物质、抗氧化酶、植物激素、光合作用等方面的变化规律,其中也有耐盐植物功能调节的研究,这有助于从多学科研究的角度评估盐胁迫的生态重要性。     

A review of plant spectral reflectance response to water physiological changes

Spectral reflectance is a new, real time and non-destructive hyperspectral remote sensing application to monitor plant water status and physiological changes. The spectral reflectance responses induced by water stress reflect the interaction and coupling of carbon, nitrogen and water cycles. A majority of previous studies focused on a specific structural or physiological effect on spectral reflectance with little attention on their interactions. This paper reviewed and synthesized the direct and indirect spectral responses caused by changes in plant water content, pigments, nutrient status, photosynthesis and chlorophyll fluorescence indices and their internal association. This paper also discussed the common approaches and the new techniques in applying spectral reflectance for detecting water status and physiological activities in plants. This paper concluded that analysis of the spectral reflectance at multiple temporal or spatial scales might have a potential application in projecting vegetation productivities, particularly in the context of climate change.     

Long‐term effect of salinity on plant quality,water relations,photosynthetic parameters and ion distribution in Callistemon citrinus

The effect of saline stress on physiological and morphological parameters in Callistemon citrinus plants was studied to evaluate their adaptability to irrigation with saline water. C. citrinus plants, grown under greenhouse conditions, were subjected to two irrigation treatments lasting 56 weeks: control (0.8 dS·m^?1) and saline (4 dS·m^?1). The use of saline water in C. citrinus plants decreased aerial growth, increased the root/shoot ratio and improved the root system (increased root diameter and root density), but flowering and leaf colour were not affected. Salinity caused a decrease in stomatal conductance and evapotranspiration, which may prevent toxic levels being reached in the shoot. Net photosynthesis was reduced in plants subjected to salinity, although this response was evident much later than the decrease in stomatal conductance. Stem water potential was a good indicator of salt stress in C. citrinus. The relative salt tolerance of Callistemon was related to storage of higher levels of Na⁺ and Cl^? in the roots compared with the leaves, especially in the case of Na⁺, which could have helped to maintain the quality of plants. The results show that saline water (around 4 dS·m^?1) could be used for growing C. citrinus commercially. However, the cumulative effect of irrigating with saline water for 11 months was a decrease in photosynthesis and intrinsic water use efficiency, meaning that the interaction of the salinity level and the time of exposure to the salt stress should be considered important in this species.     

Seed germination and salinity tolerance in plant species growing on saline wastelands

Seven plant species including three chenopods:Suaeda fruticosa, Kochia indica, Atriplex crassifolia and four grasses:Sporobolus arabicus, Cynodon dactylon, Polypogon monspeliensis, Desmostachya bipinnata, varied greatly in their seed germination and growth responses to soil moisture or salinity. The germination percentage of each species was significantly lower at soil moisture level of 25 % of water holding capacity than at the levels ranging from 50 to 125 %. Increase in salinity resulted in gradual decrease in seed germination of each species. Growth responses of species to salinity varied widely from significant decrease with slight salinity to stimulation up to salinity levels of 20 dS m^-2. Higher K⁺Na⁺ratios in plant shoots of all species compared to that in the root medium indicated selective K⁺uptake. Higher tolerance in chenopod species seems to be attendant on their ability for internal ion regulation. We are thankful to Mr. Noor Ahmad for his assistance in experimental work.     

大麦种子对盐的发芽响应模型

为了明确盐对种子发芽影响的渗透效应和离子效应共同作用方式以及量化种子发芽对盐的响应, 以两个大麦(Hordeum vulgare)品种‘Cask’和‘County’为研究对象, 设置4个恒定温度(5、12、20和27 ℃)、5个等渗的NaCl和聚乙二醇(PEG)浓度梯度(-0.45、-0.88、-1.32、-1.76和-2.20 MPa, 蒸馏水作对照), 做常规发芽实验。结果显示: (1)两个品种在NaCl溶液中比在等渗的PEG溶液中发芽率高且发芽速度快; (2) NaCl和PEG分别作为渗透剂计算出的水势模型参数值差异很大, 说明水势模型不能用来描述种子发芽对盐的响应; (3)大麦种子在盐溶液中的发芽速率与盐浓度成显著的负相关直线关系, 因此我们修订了水势模型, 将修订后的模型命名为盐度模型, 用来量化盐对大麦种子发芽的影响。与水势模型计算出的发芽时间相比, 盐度模型计算出的50%种子发芽时间与大麦种子实际发芽时间更接近; (4)大麦种子在等渗的NaCl和PEG溶液中发芽速率差异随着水势降低, 先增加后降低。据此我们提出盐的渗透效应和离子效应共同作用于种子发芽的3种情况: 第一种在低盐条件下, 主要是渗透效应起负作用; 第二种情况在中盐条件下, 渗透效应和离子效应共同起作用, 离子效用的正作用强于渗透效应的负作用; 第三种情况在高盐条件下, 离子效应逐渐开始起离子毒害的负作用。     

半红树植物玉蕊对淹水-盐度胁迫的生长及生理响应

玉蕊(Barringtonia racemosa)是典型的半红树植物,具有重要的药用及观赏价值,目前已被列为濒危植物,亟需保护.为探明不同淹水水位、淹水时长以及水体盐度对玉蕊生长的影响,筛选出适合玉蕊生存的最佳环境组合,该文以二年生玉蕊实生苗为试验材料,模拟全日潮,采用L9(34)正交试验设计,对其生长及生理指标进行分...     

Differential response to salinity and water deficit stress in Polypogon monspeliensis (L.) Desf. provenances during germination

The effects of provenance, salinity (0, 100, 200, 300 and 400 mm NaCl) and water deficit (0, -0.6, -1.1, -1.6 and -2.1 MPa mannitol solutions) on germination success of Polypogon monspeliensis were investigated. Eight Tunisian provenances from different bioclimatic origins were considered. Seed mass varied significantly between populations. Germination percentage was significantly affected by provenance, salinity and their interaction. Even at 300 mm NaCl, germination percentage of Tabarka, Kelbia and Kebili ranged from ca. 60% to ca. 85%, whereas Monastir, Gabes and El Haouaria succeeded in germinating in 200 mm NaCl. The 300 mm NaCl treatment highly reduced germination of Monastir and El Haouaria, and inhibited that of Gabes. Soliman and El Jem were the least salt-tolerant provenances. The severity of water deficit impact on seed germination was also provenance-dependent, especially at osmotic potentials of -1.1 to -1.6 MPa. At -1.6 MPa, germination percentage of Tabarka, Monastir and Kebili was close to 80%, while that of Gabes, El Jem and Kelbia was 0%, 5% and 20%, respectively. Regardless of provenance, germination was strongly impaired at -2.1 MPa. The variability of stress tolerance in P. monspeliensis could be of practical significance in programmes aimed at restoring arid and salt-affected lands since it allows use of provenances that germinate and establish successfully under unfavourable conditions prevailing in such zones.     

Some important physiological selection criteria for salt tolerance in plants

Undoubtedly, plant breeders have made a significant achievement in the past few years, improving salinity tolerance in a number of potential crops using artificial selection and conventional breeding approaches, although molecular biology approaches are currently being intensively pursued for achieving this goal. However, most of the selection procedures used so far, were based merely on differences in agronomic characters. Agronomic characters represent the combined genetic and environmental effects on plant growth, and include the integration of the physiological phenomena conferring salinity tolerance. In fact, physiological criteria are able to supply more reliable information than agronomic characters. Although there are large numbers of reports in the literature mainly dealing with water relations, photosynthesis, and accumulation of various inorganic ions and organic metabolites in individual crops, there is little information available on the use of these attributes as selection criteria for improving salt tolerance through selection and breeding programs. In this review, the major adaptive components of salt tolerance such as osmotic adjustment, photosynthesis, water relations and ion relations are reviewed. In view of the complexity of salt tolerance and its great variation at intra-specific and inter-specific levels, it is difficult to identify single criteria, which could be used as effective selection targets. Rather it is most meaningful if physiological and biochemical indicators for individual species are determined rather than generic indicators.     

植物硒吸收转化机制及生理作用研究进展

硒是大多微生物、动物及人类的必要微量元素,但其在植物生长发育中的生理作用至今存在争议.较低浓度硒具有促进植物生长、提高植物耐受能力的功能,而大部分植物在高浓度下表现出中毒现象.随着人类对摄入硒及环境硒污染问题的认识加深,作物硒生物强化与硒污染植物修复问题引起重视,推动了对硒在植物中的吸收积累及代谢调控的研究.近年来对植物硒吸收及转化的研究表明,不同硒水平下植物对硒吸收积累及生理响应存在差异,土壤环境因素对植物硒吸收及转化具有重要影响,对高聚硒植物硒代谢研究逐渐揭示出硒在植物体内的转化过程和调控机理等.本文总结了目前硒生物强化与植物修复方面的研究进展,对环境中硒分布特点、植物硒吸收及其影响因素、植物体内硒转化及其过程调控关键酶,以及硒在植物中的生理作用等进行了综述,并对植物硒生理及分子机制未来研究方向进行展望.     

荒漠植物功能性状及其多样性对土壤水盐变化的响应

植物功能性状及其多样性对环境变化的响应研究有助于揭示极端环境下植物适应策略和群落构建机制。通过实地调查和实验分析,研究艾比湖荒漠植物形态、生理和化学等8个功能性状的特征,并从多维性状和一维性状角度揭示功能多样性对土壤水分和盐分变化的响应规律。结果表明:高水盐环境下(SW1),(1)群落加权株高、叶绿素含量(SPAD)及叶片碳(C)和钙(Ca)含量显著高于低水盐环境,叶片氮(N)、磷(P)、硫(S)含量在不同水盐环境间无显著差异。(2)SW1环境下,沿乔木-小乔木-灌木-草本层次,上层生活型植物性状值普遍高于下层植物,其中灌木叶片仅N、钾(K)含量显著高于草本;沿该生活型层次植物性状呈趋同变化。(3)低水盐环境下(SW2),乔木叶片性状差异特征与SW1相似;小乔木叶片C、N含量分别显著高于和低于灌木及草本;相比于草本,灌木SPAD、S含量显著高,K含量显著低,株高、C、N、P含量差异不显著;SW2环境下各生活型植物性状呈趋同变化。(4)SW1环境下多维功能丰富度、功能离散度显著高于SW2环境,但均匀度无显著差异。(5)一维功能均匀度在不同水盐环境间均无显著差异,但化学性状的均匀度总体高于植物株高;高水盐环境下叶片N、S和Ca的功能分异指数显著高于低水盐环境。研究为掌握胁迫环境下的植物适应策略和荒漠植被恢复提供参考。