Antioxidant and Photosynthetic Responses of Cotton to Soil Drought Stress during Flowering and Fruiting Stage

[Objective] The purpose of this study was to examine potential drought tolerance mechanisms in cotton (Gossypium hirsutum L.). Biochemical (antioxidant, protein and compatible osmolyte) and physiological (photosynthesis) responses to drought stress during the flowering and fruiting stages were examined. [Method] Using two cotton genotypes (A001 and A705) with different drought tolerance, a pot study was conducted in 2016 with treatments consisting of control (well-watered) and water stress. Water stress treatment was designed as withholding water from the pots until stomatal closure followed by limited water supply for 25 days where water-stressed plants received 40% of the optimum quantity of water. Measurements were made on soluble protein, proline and malonaldehyde (MDA) concentrations, peroxidase (POD) activity and photosynthetic characteristics (net photosynthetic rate P_n, transpiration rate E, stomatal conductance G_s) during the period of water stress. [Result] The soluble protein concentration was decreased and POD activity and MDA level were increased in the leaf subtending cotton boll of A001 under water deficit when compared with the control, but no response was observed in A705. Proline level responded to water deficit inconsistently between the two genotypes and across all sampling dates. Water stress significantly decreased P_n, E and G_s in the main stem leaves for both A001 and A705. [Conclusion] The results indicated that POD, soluble protein and MDA are involved in A001 and A705 responses to water deficit, and A705 is more tolerant to soil drought than A001.     

棉花不同钾效率基因型对水分和低钾胁迫的响应研究

为探明不同钾效率棉花基因型在水分和低钾胁迫条件下的差异,采用盆栽试验,对2种基因型棉花一些生理生化指标及生物学产量的差异性进行研究。结果表明,棉花在逆境胁迫条件下,其生长状况及生理生化过程中发生一系列适应性改变,不同基因型、不同生育时期,其抗逆性也不同。表现为：不同处理条件下,棉花钾高效基因型(103)叶绿素含量指数高于棉花钾低效基因型(122),生物学产量也较高。同时103叶片丙二醛(MDA)含量低于122,表明103抗逆性较强。2种基因型间可溶性糖与脯氨酸(Pro)含量以及过氧化物酶(POD)活性变化一致,差异不显著。     

Characterization of Barley Leaf Tolerance to Drought Stress by Chlorophyll Fluorescence and Electron Paramagnetic Resonance Studies

Two kinds of barley genotypes with various water‐stress tolerances, tolerant Cam/B1 and sensitive Maresi, were subjected to 10‐day soil‐drought stress in seedling and flag leaf developmental phases. After this time, both genotypes regardless of the growth stage showed a decrease in quantum yield of PSII photochemistry (Φ_PSII) upon stress treatment; however, this effect was stronger in the sensitive plants than in the tolerant ones. The drought stress in the flag leaf stage was associated with an increase in superoxide dismutase (SOD) level in both genotypes, whereas in seedlings, this effect was observed only for Maresi. The activity of other enzymes (catalase and peroxidase) was changed only in small degree. An increase in proline levels and activities of Δ¹‐pyrroline‐5‐carboxylate synthetase (P5CS) and ornithine delta‐aminotransferase (OAT) were observed independently of genotype and the phase of plant development, whereas the activity pyruvate dehydrogenase (PDH) decreased in tolerant genotype. Moreover, changes in the concentration of monocarbohydrates (glucose and fructose) and dicarbohydrates (saccharose, raffinose and maltose) were found: in seedlings, the amount of all soluble sugars increased, while in flag leaves decreased. The drought treatment resulted in a drop in starch level in the tolerant genotype, but in the sensitive one, the content of this substance increased in both developmental stages. EPR studies allowed the determination of the amount and character of organic radicals present in leaves. In control conditions, the content of these radical species was higher in the sensitive genotype than in tolerant one and decreased upon water stress, with the exception of flag leaves of the sensitive plant. Simulation procedure revealed four types of signals in the EPR spectra. One of them was attributed to a chlorophyll a cation and decreased upon drought. The second, ascribed to semiquinone radicals, reflected the redox balance disturbed by water deficit. The two remaining signals were connected with carbon‐centred radicals situated in the carbohydrate matrix. Their number was correlated with starch concentration.     

Interactive Effects of Sudden and Gradual Drought Stress and Foliar‐applied Glycinebetaine on Growth,Water Relations,Osmolyte Accumulation and Antioxidant Defence System in Two Maize Cultivars Differing in Drought Tolerance

Influence of sudden and gradual drought stress (DS) and foliar‐applied glycinebetaine (GB) on growth, water relations, osmolyte accumulation and antioxidant defence system were investigated in the plants of two maize (Zea mays L.) cultivars, that is, drought‐tolerant Shaandan 9 (S₉) and drought‐sensitive Shaandan 911 (S₉₁₁). Sudden DS caused less accumulation of GB and free proline, but a more accumulation of malondialdehyde (MDA), which resulted in a greater reduction in leaf relative water content (RWC) and dry matter (DM) in both cultivars compared with the gradual DS. Exogenous GB application caused a rise in DM, RWC, contents of GB and free proline as well as the activities of SOD, CAT and POD along with a decline in MDA content to various extent in both cultivars under both types of DS. A more pronounced effectiveness of GB application was observed in S₉₁₁ than that in S₉ under the same type of DS. It seemed that the more serious damage of DS was on maize plants, and the better positive role of GB was observed in terms of mitigating the adverse effects of DS. From this study, it was possible to propose that hardening for drought resistance by gradual DS treatment and GB application are effective to make plants robust to thrive under water‐deficit conditions.     

Genotypic Variation in Wheat in Response to Water Stress and Abscisic Acid-Induced Accumulation of Osmolytes in Developing Grains

Two wheat genotypes differing in water stress sensitivity (C306, relatively tolerant; HD2329, relatively susceptible) were water stressed during early grain filling by withholding water for 7 days at watery‐ripe (WR) stage and examined for water status, abscisic acid (ABA) and osmolytes in grains as well as in flag leaf (FL). Both the genotypes differed significantly from each other in endogenous levels of ABA, proline, glycine betaine, total soluble sugars, reducing sugars, sucrose and potassium. The tolerant genotype showed higher content of ABA, proline, glycine betaine, total sugars, reducing sugars and had higher water content in its FL and grains than the susceptible genotype, which contained more of glycine beatine and potassium but had lower ABA and water content in its FL and grains. Although carbohydrates constituted the major amount of all the solutes, proline and glycine betaine increased manifold during stress. Exogenous application of 2 μm ABA at 5 days after anthesis to FL of stressed plants increased the endogenous content of ABA, accelerated the accumulation of osmolytes, improved the water status of FL and grains that resulted in higher grain weight, especially in the susceptible genotype. Differential response of contrasting wheat genotypes to water stress may be governed by ABA‐dependent solute accumulation in grains and FL.     

土壤水分胁迫下茶树部分渗透调节物质的变化

为了了解不同茶树品种对干旱环境的适应性,分析了土壤水分胁迫对茶树部分渗透调节物质含量变化的影响。以茶树‘铁观音’和‘福鼎大白茶’2年生幼苗为材料,采用盆栽试验的方法,研究了在正常供水(土壤含水量为田间最大持水量的75%)、轻度水分胁迫(55%)、中度水分胁迫(35%)和重度水分胁迫(20%)条件下,茶树部分渗透调节物质的变化情况。结果表明,正常供水条件下,‘铁观音’叶片相对含水量、脯氨酸含量低于‘福鼎大白茶’,可溶性蛋白和可溶性糖含量高于‘福鼎大白茶’;水分胁迫下‘铁观音’、‘福鼎大白茶’叶片相对含水量随胁迫程度的加大而降低,可溶性蛋白质、可溶性糖以及脯氨酸的含量随胁迫程度的加大而增多,但在重度胁迫下,‘福鼎大白茶’的可溶性蛋白质及脯氨酸含量下降。在相同的水分胁迫条件下,‘铁观音’叶片相对含水量的降幅都小于‘福鼎大白茶’,而可溶性蛋白、可溶性糖和脯氨酸含量的增幅都比‘福鼎大白茶’大。表明在土壤水分胁迫下‘铁观音’的渗透调节适应能力高于‘福鼎大白茶’。     

不同增温处理对基质育苗移栽棉缓苗期部分生理生化指标的影响

试验以露地移栽为对照,研究了地膜覆盖和地膜覆盖加拱棚2种增温处理对基质育苗移栽棉花缓苗期的影响,结果表明,在缓苗期内,不同的增温处理对叶绿素影响不大,丙二醛MDA和脯氨酸含量均随生育进程呈现先增加后下降趋于稳定的趋势,覆膜和覆膜加拱棚较露地移栽含量低,温度高有利于缓解棉苗的受胁迫程度;3种不同处理条件下,超氧化物歧化酶...     

消落带植物南川柳对干旱胁迫的生理响应

为了探明消落带植物南川柳(Salix rosthornii Seemen)的耐旱特性,为消落带种群构建和植物选择提供理论依据,在盆栽条件下,对南川柳1年生幼苗采用控水方式进行干旱胁迫处理,同时设置对照组进行正常灌溉,并测定叶片相对含水量(RWC)、电解质渗漏(EL)、丙二醛(MDA)等一系列与植物耐旱能力相关的生理指标以及抗氧化性酶活性的变化,系统讨论了南川柳对干旱的生理响应。结果表明：在干旱胁迫下南川柳幼苗叶片具有较强的水分保持能力,并且在复水后有相对较快的恢复能力;10天和20天的干旱胁迫对南川柳叶片电解质渗漏的影响与对照相比差异不显著,随胁迫时间的持续,EL和MDA都显著升高。在干旱胁迫下,南川柳幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性整体呈先升高后降低的趋势,其中CAT对胁迫最为敏感,而POD响应相对较为缓慢;在复水20天后3种酶活性有所恢复,但均未恢复到对照的水平。     

Accession Variation for Salt Tolerance in Proso Millet (Panicum miliaceum L.) Using Leaf Proline Content and Activities of Some Key Antioxidant Enzymes

Inter‐accession variation for salt tolerance of Panicum miliaceum (proso millet) was appraised using leaf proline content and activities of antioxidant enzymes as selection criteria. Eighteen accessions of proso millet were grown under control conditions and after 14 days subjected to saline (120 mm NaCl) stress for 4 weeks. Salt stress substantially decreased relative water content (RWC), while increased leaf free proline and malondialdehyde (MDA) and activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of all accessions of proso millet. The difference among the accessions of P. miliaceum was significant in yield as well as in the activities of antioxidant enzymes analyses. On the basis of seed yield (expressed as per cent of control), of 18 accessions, three were categorised as salt‐tolerant (008211, 008214 and 008226), seven as moderately tolerant (008210, 008213, 008216, 008220, 008222, 008223 and 008242) and eight as salt‐sensitive (008208, 008215, 008217, 008218, 008221, 008225, 008230 and 008236). Of all P. miliaceum accessions, 008211, 008226, 008215 and 008218 were relatively higher in proline, 008214 and 008221 in MDA contents, 00812, 008225, 008236, 008222 and 008242 in SOD activity and 008218, 008220, 008211 and 008226 in POD and CAT enzyme activities. Thus, because of differential response of high or low seed yielded accessions in accumulation of proline and antioxidant enzyme activities, these variables were not found effective criteria for discriminating the P. miliaceum accessions for salt tolerance.     

转晚期胚胎发生丰富蛋白(LEA)基因棉花及抗旱性分析

本研究将紫杆柽柳(Tamarix and rossowii Litv)晚期胚胎发生丰富蛋白(LEADQ663481)基因导入新疆早熟棉新陆早18号,通过冬季海南加代、夏季新疆继代的方法获得T3代转基因棉花株系。从40株大田卡那霉素检测阳性植株中,经过PCR筛选证明3株为阳性的转化株。在室内条件下,对转化株幼苗进行水培实验,并用12%(w/v)PEG-6000处理12h模拟干旱胁迫。结果显示,干旱胁迫之后,转LEA基因棉花基因表达量显著增加;丙二醛生成量显著降低;游离脯氨酸、可溶性糖、可溶性蛋白的生成量显著增加;棉花表型分析也证明了转LEA基因棉花抗旱性有提高。培养45d后,转LEA基因棉花的生物量高于非转基因棉花。本研究结果表明,在干旱胁迫条件下,转LEA基因棉花表现出了优良的生长和生理优势,显示出转LEA基因棉花能提高棉花的抗旱能力。     

多酚氧化酶基因NtPPOE差异表达的效应分析

为研究烟草中多酚氧化酶基因的功能,本研究从GenBank中挑选一个烟草多酚氧化酶基因Polyphenol oxidase E(基因登录号:NW_015916967.1),命名为NtPPOE。构建NtPPOE基因的CRISPR载体和超表达载体,分别得到NtPPOE基因抑制/过量表达的转化植株。研究表明,基因敲除植株NtPPOE基因相对表达量降低,PPO活性降低,多酚类物质含量升高;超表达植株NtPPOE基因相对表达量升高,PPO活性升高,多酚类物质含量降低。NtPPOE基因表达量与PPO酶活性呈正相关,与多酚类物质含量呈极显著性负相关,NtPPOE基因的表达影响了烟草多酚代谢。本研究通过分析NtPPOE基因差异表达产生的效应,初步验证了NtPPOE基因的功能,并得到了NtPPOE基因抑制/过量表达的突变植株,为PPO基因功能研究和不同PPO活性品种的育种提供材料基础。     

中棉所29栽培技术及其生理特性研究

研究表明 ,抗虫杂交棉中棉所 2 9苗期叶绿素、IAA含量高 ,MDA含量低 ,SOD、CAT酶活性高 ,膜脂过氧化程度低 ,棉苗抗胁迫能力强 ,苗质好 ,生长健壮 ;中后期 MDA、ABA含量和 POD活性升高 ;整个生育期均保持较高的光合强度 ,N素营养充足 ,利于高产优质 ;在华北平原一熟种植最佳播期在 4月下旬 ,中等肥水条件下最佳密度为 5.2 5万株· hm- 2 ;对缩节安化调反应不敏感 ,应看苗化调     

Variability in Osmotic Stress Tolerance of Starch Potato Genotypes (Solanum tuberosum L.) as Revealed by an In Vitro Screening: Role of Proline,Osmotic Adjustment and Drought Response in Pot Trials

Solanum tuberosum (potato) as a drought sensitive plant is also one of the most promising plants to meet the demands for food and starch of a growing population. Distinguishing genotypes into tolerant and susceptible is therefore of utmost interest. We subjected eighteen potato genotypes and two wild species, S. tarijense and S. chacoense, to osmotic stress applied in vitro by addition of 0.2 m sorbitol to a solid medium. Here, we report that a ratio of root:shoot dry mass (DM) together with the SSI (stress susceptibility index, equivalent to drought susceptibility index by Fischer and Maurer, Aust. J. Agron. Res., 29, 1978) of shoot DM were found to be relevant parameters to characterize genotypes in vitro for their osmotic stress tolerance. Drought stress data from pot trials in a rainout shelter (2013 and 2015) correlated poorly with the data obtained in in vitro experiments. However, the most tolerant and most sensitive genotypes in vitro were also categorized to be more tolerant or sensitive than the average to drought stress in vivo. Both, under in vitro and in vivo conditions, proline displayed an increase under osmotic stress conditions in nearly all potatoes tested, but no direct correlations were found to stress tolerance. However, a genotype classified as tolerant displayed earlier proline accumulation. Proline is thought of as one factor for plants to withstand stressful conditions, but cannot be used to distinguish potato genotypes for their stress tolerance to osmotic stress in vitro. Analysis of the osmotic potential of in vitro and in vivo stressed plants displayed a general increase compared to the control.     

花生种子黄酮及多酚含量的生态差异分析

为探讨生态环境是否对花生种子黄酮及多酚产生影响,及两者变化与初生代谢物脂肪和总糖含量变化的相关性,选用全国广泛栽培的、种子黄酮及多酚含量具有极显著差异的花生品种16个,在多个试验点进行2年种植,鉴定种子总黄酮、总多酚、脂肪和总糖含量,结果表明,基因型效应显著影响花生种子黄酮及多酚含量,濮花23号为高TFC品种,豫花9327为高TPC品种。生态环境对花生种子黄酮及多酚含量具有极显著效应,合肥试验点为适于黄酮和多酚形成的种植区。此外,黄酮及多酚二次生代谢物与脂肪、可溶性蛋白和总糖等初生代谢物在地域间变化趋势年纪间不一致。     

三个不同耐高温棉花基因型主茎叶的生理生化特征

 对不同高温耐性棉花主茎叶的生理生化特性及其变化规律进行了比较研究。结果表明,耐高温棉花HLY细胞膜热稳定性显著高于敏感品系TS18,而与中度敏感品系XYM68在苗期和盛蕾期没有明显差异,到盛花和结铃盛期差异显著;三个材料之间的叶片脯氨酸含量除苗期外均存在显著差异,可溶性糖含量在结铃盛期才差异显著,而可溶性蛋白质含量差异不明显;HLY叶片叶绿素含量在盛花期和结铃盛期显著高于XYM68和TS18,而净光合速率在整个生育时期都显著高于XYM68和TS18。主茎叶细胞热稳定性、脯氨酸、可溶性糖及净光合速率能较好区分耐高温与敏感材料,这为耐高温棉花的筛选与鉴定提供了重要的生理生化指标。     

轻简化基质育苗棉苗栽前离床期耐受生理特性研究

【目的】明确棉花轻简化基质育苗技术下的幼苗离床耐受生理相关特性,为其安全存放和运输保护提供理论支持。【方法】设置了育苗基质添加保水剂和不添加保水剂的处理,以中棉所50为材料,研究了29 d苗龄的幼苗不同离床和复水条件下的相关生理指标变化。【结果】室内条件下棉苗离床的耐受过程中,幼苗叶片逐步失水,引起从叶片外部表层细胞结构到内部生理的一系列变化,最终影响移栽成活率。其中,离床3 d内是安全期,叶片含水量的损失不到5%,且及时复水后能达到幼苗离床前初始状态的98%以上,移栽成活率均在99%以上;此时叶片表层细胞结构相对完整,细胞连接相对平滑,保卫细胞相对饱满。离床5 d为临界期,此时复水仅能达到初期的93%左右;第5至7天叶片失水最快,这个阶段相对含水率日均下降15百分点;当失水降到50%以下(11 d后)时,叶片表层细胞皱缩较严重,细胞壁皱褶明显,气孔塌陷较深,复水后恢复能力弱。失水过程中真叶内脯氨酸、丙二醛含量和过氧化物酶活力随离床时间增加而上升/增加,过氧化氢酶和超氧化物歧化酶活力变化在前5 d上升,5 d后开始下降。【结论】保水剂有利于维持离床棉苗体内水分,缓解离床期干旱胁迫。     

追施不同形态氮肥对不同钾效率基因型棉花生长及产量品质的影响

【目的】探讨高、低供钾水平下,追施氮肥形态对棉花生长、钾素吸收利用以及产量、品质的影响。【方法】选择钾高效棉花品种辽棉18、冀棉958和钾低效棉花品种新棉99B为材料,进行营养钵培养试验,设置38.01mg·kg~(-1)和152.24 mg·kg~(-1)两个供钾水平,追施铵态氮肥(硫酸铵)和硝态氮肥(硝酸钙)两种形态氮素肥料。【结果】供钾不足会降低棉花果枝始节和单株成铃数,高钾处理棉花干物质积累量、钾累积量、钾利用指数以及产量显著高于低钾处理;与追施硝态氮肥相比,追施铵态氮肥会降低棉株高度、果枝数和单株成铃数,减少籽棉产量和总干物质积累量;追施铵态氮肥处理棉花对钾素的吸收和利用显著低于追施硝态氮肥处理。【结论】钾低效基因型品种棉花在钾素供应不足时对追施铵态氮肥更敏感,且棉花成熟越晚受到追施肥料氮素形态影响越大。     

打顶后涂抹萘乙酸对海岛棉根系活力及丙二醛含量的影响

为了揭示新疆棉花栽培技术中“打顶”措施与棉花早衰问题之间的关系,在水培条件下研究了低氮(1.0×10-3 mol·L-1)和高氮(4.0×10-3 mol· L-1)两种供氮水平下,不打顶、打顶、打顶后涂抹羊毛脂和打顶后涂抹羊毛脂+萘乙酸处理对棉花功能叶丙二醛含量和根系活力的影响.结果表明:在两种供氮水平下,棉花打顶、打顶后涂抹羊毛脂和涂抹羊毛脂+萘乙酸处理比不打顶处理根系活力增幅分别为94.4％～110.0％、55.9％～85.7％和51.5％～147.4％,差异显著；丙二醛(MDA)含量增幅分别为12.0％～17.3％、5.2％～6.5％和9.7％～10.9％,差异不显著.打顶和打顶后涂抹萘乙酸可促进棉花根系生长,提高根系活力和总吸收面积.     

Impact of nitrogen supply on leaf water relations and physiological traits in a set of potato (Solanum tuberosum L.) cultivars under drought stress

Improved adaptation of potato to limited water availability is needed for stable yields under drought. The maintenance of the cell water status and protection of cellular components against dehydration are important for drought tolerance, and the N status of plants affects the regulation of various respective metabolic processes. A 2‐year pot trial with 17 potato cultivars was conducted under a rain‐out shelter including two water regimes and two N‐levels to investigate genotypic differences concerning osmotic adjustment (OA) and relevant biochemical traits in relation to nitrogen (N) supply. Drought stress resulted in a rapid decrease in the leaf osmotic potential. The N, protein and proline contents increased under drought, while the N protein/N_Kjeldahl ratio decreased. Initially, total soluble sugars increased at both N‐levels but dropped back to the control level at high N‐availability under prolonged drought while remaining high in N‐deficient plants. Results indicate that potatoes have only a limited capacity of active OA and that increasing sugar and proline concentrations are rather associated with the protection of cellular components. High N supply promoted the N protein/N_Kjeldahl ratio at short‐term drought and enhanced proline accumulation. Significant genotypic differences were observed for all investigated traits.     

Remobilization of Proline and Other Nitrogen Compounds from Senescing Leaves of Maize under Water Stress

The effects of water stress around anthesis on proline accumulation and translocation from leaves of two maize cultivars (DA 4F37 and DA XL636) were studied. Water stress increased leaf proline content only in DA 4F37, while proline in leaf exudates was detected only in DA XL636 water-stressed plants. Proline translocation was not associated with increased nitrogen remobilization from leaves. The accumulating proline cultivar DA 4F37 showed a higher osmotic adjustment capacity than DA XL636. Leaf proline content in water-stressed DA 4F37 plants varied with daytime. High proline concentration during the morning was found in leaves with high relative water content. This evidence would support the hypothesis that proline is involved in osmotic adjustment.