逆境条件下小麦种子活力与种子萌发相关酶活性及其基因表达的关系

分析不同基因型小麦品种逆境萌发过程中种子萌发相关酶活性及基因表达差异,明确在逆境条件下,种子活力与种子萌发相关酶活性及基因表达量的关系.通过标准发芽试验和逆境(冷浸、人工老化、干旱胁迫)发芽试验,测定4个小麦品种种子活力、萌发过程中可溶性总糖和可溶性蛋白含量、α-淀粉酶活性、半胱氨酸蛋白酶活性及相关基因表达量.结果表明:干旱、人工老化和冷浸胁迫3种逆境对种子活力都有一定影响.不同萌发条件下,可溶性总糖含量呈现先小幅度升高后小幅度降低再迅速升高的趋势;而可溶性蛋白含量随着萌发时间的延长呈现逐渐下降的趋势.α-淀粉酶活性整体呈现逐渐升高的趋势,但在冷浸胁迫处理后,豫农949和轮选061的α-淀粉酶活性在萌发60 h后出现下降.半胱氨酸蛋白酶活性整体呈先降低后升高的趋势,但在干旱胁迫条件下,豫农949、豫麦49-198和轮选061的半胱氨酸蛋白酶活性呈现先升高后降低再升高的趋势.不同逆境萌发条件下,α-AMY(α-淀粉酶基因)表达量整体呈先上升后下降的趋势.冷浸胁迫处理后,轮选061的α-AMY表达量高于对照,在其他逆境萌发条件下,4个品种的α-AMY表达量均低于对照;人工老化处理后,长4738的CP(半胱氨酸蛋白酶基因)表达量与对照差异不显著,在其他逆境萌发条件下,4个品种的CP表达量均高于对照.种子萌发期间,不同萌发条件下α-淀粉酶和半胱氨酸蛋白酶活性与其基因表达并没有直接关系,α-淀粉酶活性与可溶性总糖含量达到显著正相关,半胱氨酸蛋白酶活性与可溶性蛋白含量的相关性不显著.在标准发芽条件下,α-淀粉酶活性与活力指数呈显著正相关,而在逆境萌发过程中,其相关性不显著.冷浸胁迫处理后,半胱氨酸蛋白酶活性与活力指数呈显著正相关,但在标准发芽、干旱胁迫、人工老化处理后,其相关性不显著.     

Effect of laser pretreatment on germination and membrane lipid peroxidation of Chinese pine seeds under drought stress

The germination of laser-irradiated Chinese pine seeds was carried out under drought stress.The activities of superoxide dismutase (SOD) and peroxidase (POD),and the content of malondialdehyde (MDA) were determined.Results showed notably increased germination percentage,root length,vitality index and fresh weight.The SOD and POD protective enzyme system activity of the Chinese pine seedlings obviously rose.It can be concluded that the germination and juvenile resistance of Chinese pine seeds under drought stress are enhanced after laser processing.     

Morpho-physiological and molecular characterization of drought tolerance traits in Gossypium hirsutum genotypes under drought stress

Drought stress is one of the major abiotic stresses affecting lint yield and fibre quality in cotton. With increase in population, degrading natural resources and frequent drought occurrences, development of high yielding, drought tolerant cotton cultivars is critical for sustainable cotton production across countries. Six Gossypium hirsutum genotypes identified for drought tolerance, wider adaptability and better fibre quality traits were characterized for various morpho-physiological and biochemical characters and their molecular basis was investigated under drought stress. Under drought conditions, genotypes revealed statistically significant differences for all the morpho-physiological and biochemical traits. The interaction (genotype × treatment) effects were highly significant for root length, excised leaf water loss and cell membrane thermostability indicating differential interaction of genotypes under control and stress conditions. Correlation studies revealed that under drought stress, relative water content had significant positive correlation with root length and root-to-shoot ratio while it had significant negative correlation with excised leaf water loss, epicuticular wax, proline, potassium and total soluble sugar content. Analysis of expression of fourteen drought stress related genes under water stress indicated that both ABA dependent and ABA independent mechanisms of drought tolerance might be operating differentially in the studied genotypes. IC325280 and LRA5166 exhibited ABA mediated expression of stress responsive genes and traits. Molecular basis of drought tolerance in IC357406, Suraj, IC259637 and CNH 28I genotypes could be attributed to ABA independent pathway. Based on physiological phenotyping, the genotypes IC325280 and IC357406 were identified to possess better root traits and LRA5166 was found to have enhanced cellular level tolerance. Variety Suraj exhibited good osmotic adjustment and better root traits to withstand water stress. The identified drought component trait(s) in specific genotypes would pave way for their pyramiding through marker assisted cotton breeding.Electronic supplementary materialThe online version of this article (10.1007/s12298-020-00890-3) contains supplementary material, which is available to authorized users.     

渗透胁迫下小麦根系渗透调节与根冠淀粉水解的研究

用不同浓度的PEG—600对抗旱性不同的小麦幼苗进行渗透胁迫处理,研究了小麦幼苗根系的淀粉酶活性、可溶性糖含量、渗透势、渗透调节能力和根冠淀粉的水解状况。结果表明,随着渗透胁迫程度的加重,抗旱性强的小麦品种昌乐5号和北农2号根系渗透势和饱和渗透势的降低程度大于抗旱性弱的小麦品种鲁麦5号和921842,并且抗旱性强的小麦品种根系的渗透调节能力大于抗旱性弱的小麦品种。随着渗透胁迫程度的加重．各品种小麦根冠淀粉粒均有不同程度的减少。而抗旱性强的品种根冠淀粉粒的减少程度小于抗旱性弱的品种;抗旱性强的小麦品种根系淀粉酶活性显著高于抗旱性弱的小麦品种,但是,随着渗透胁迫程度的加重,抗旱性弱的品种淀粉酶活性增加的幅度远高于抗旱性强的品种。可溶性糖含量的变化趋势与淀粉酶活性的变化趋势一致．即渗透胁迫下根冠淀粉水解程度大的小麦品种,可溶性糖的含量高。但根冠淀粉水解在根系的渗透调节以及在小麦适应水分胁迫中的作用还有待于进一步探讨。     

Changes in Germination and Seedling Traits of Sesame under Simulated Drought

Drought is considered one of the leading abiotic constraints to agricultural crop production globally. Present study was conducted to assess the effects of different drought treatments (viz. Control, 10% PEG, and 20% PEG) on seed germination, germination indices, seedling traits, and drought tolerance indices of sesame. Our results showed that maximum reduction in the studied parameters was observed at higher PEG concentration (i.e., 20% PEG). As compared to control, the drought treatments viz. 10% and 20% PEG decreased the values for germination indices, such as germination percentage, coefficient of variation of germination time, germination index, and seedling vigor index. Similarly, for seedling traits, the values were decreased for root length, shoot length, root shoot ratio, root fresh weight, shoot fresh weight, root dry weight and shoot dry weight under 10% and 20% PEG treatments significantly in comparison with control. Furthermore, relative to control, the values for drought tolerance indices, such as germination drought tolerance index, root length drought tolerance index, shoot length drought tolerance index, total seedling length drought tolerance index, root fresh weight drought tolerance index, shoot fresh weight drought tolerance index, total fresh weight drought tolerance index, root dry weight drought tolerance index, shoot dry weight drought tolerance index and total dry weight drought tolerance index were also reduced under 10% and 20% PEG treatments, respectively. Our results confirms that drought impact on seed germination and seedling traits could be quantified by using different indices which can further help to design drought adaptation and mitigation strategies. Based on these results it can be concluded that germination indices, seedling traits, and drought tolerance indices have great potential to simulate drought stress impacts on different crop traits thus they should be used in all kinds of stress related studies.     

干旱胁迫下华北驼绒藜种子大小及苞片对萌发和幼苗生长的影响

干旱是影响荒漠区植物种子萌发和幼苗生长的关键因素.以多年生强旱生半灌木华北驼绒藜为对象,研究了不同干旱程度(0、100、200、300和400g·L-1PEG6000)下,种子大小及苞片有无对种子萌发及幼苗生长的影响.结果表明:干旱胁迫显著抑制了种子萌发和幼苗地上部的生长.100和200 g ? L-1 PEG6000...     

基于小麦种子发芽逆境抗逆指数的种子活力评价

以16个小麦品种的种子为材料,通过标准发芽、逆境发芽和田间出苗试验,测定不同基因型小麦品种的种子活力,以不同发芽条件下种子活力指数的抗逆指数和田间出苗率作为衡量抗逆性的指标,利用主成分分析、聚类分析对种子活力进行综合评价.结果表明: 干旱胁迫、人工老化和冷浸胁迫3种逆境对种子活力都有一定的影响.人工老化抗逆指数和冷浸胁迫抗逆指数与田间出苗率呈显著正相关,干旱胁迫抗逆指数与田间出苗率的相关性不显著.通过主成分分析和聚类分析将16个小麦品种划分为3类、豫农949、豫麦49-198、鲁原502、郑育麦9987、石麦21、山农23号、石新828为高活力品种;许农5号、豫农982、唐麦8号、济麦20、济麦22、济南17号、山农20为中活力品种;长4738和轮选061属低活力品种.     

Salt Stress Induced Changes in Growth and Enzyme Activities in Germinating Phaseolus Mungo Seeds

NaCl salt stress induced changes in growth and enzyme activities in blackgram (Phaseolus mungo L.) seeds during germination were studied. A decrease in germination percentage, root length, shoot length, and fresh mass was noticed with an increase in NaCl concentration. With the increase in NaCl concentration and duration of stress proline content increased and catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities decreased.     

用渗透胁迫鉴定小麦种子萌发期抗旱性的方法分析

本以聚乙二醇(PEG)-6000、甘露醇和蔗糖作为渗透剂模拟水分胁迫,胁迫溶液渗透势范围在-0．25MPa到-1．50MPa,分析适于进行小麦种子水分胁迫萌发试验的条件,以鉴定小麦萌发期的抗旱性。结果表明,蔗糖溶液易诱发霉茵,胚芽不能正常生长。渗透势为-0．25MPa的PEG-6000及-0．50MPa的甘露醇胁迫已经显抑制了胚芽伸长;-0．50MPa的PEG-6000及-1．00MPa的甘露醇显抑制种子萌发,随着胁迫强度增加,种子相对发芽率及胚芽长度减小,主要是因为渗透胁迫降低了种子吸水速度,胚芽的相对含水量和渗透势均低。在渗透势相同的胁迫条件下,PEG-6000对小麦种子萌发各项检测值的抑制作用均大于甘露醇。如果目的是通过鉴定小麦种子在高渗溶液中的萌发情况,评价萌发期的抗旱性。选用-0．50MPa的PEG-6000或-1．00MPa的甘露醇较为理想,若同时考虑降低试验成本,则应首选-0．50MPa的PEG-6000。     

不同西瓜基因型对干旱胁迫的生理响应及其抗旱性评价

以来源于不同地区的12个西瓜基因型为试材,采用盆栽控水的方式进行持续干旱处理,研究干旱胁迫对西瓜幼苗株高、根长、鲜质量及干物质积累等生长状况的影响,比较不同基因型材料对干旱胁迫的生理响应差异,同时依据旱害指数对其抗旱性进行直接评价,并采用隶属函数法进一步验证和综合评价.结果表明: 干旱处理下,12个西瓜基因型对干旱胁迫的耐受能力存在明显差异,各基因型开始出现旱害症状的时间和发生旱害的程度各不相同.干旱胁迫降低了西瓜幼苗的株高、地上、地下鲜质量和地上干物质积累量,普遍提高了根冠比,而对根长和地下干质量存在正向和负向两种不同的影响.干旱处理后,西瓜叶片的相对含水量和叶绿素含量均不同程度降低,丙二醛、过氧化氢和超氧阴离子含量增加,脯氨酸大量积累,而可溶性蛋白含量以及抗氧化酶活性则因基因型的不同而表现出不同的结果.分析认为,3个野生型材料M20、KY-3和Y-2为抗旱性强的西瓜种质,Y34、金美人和04-1-2为敏感种质,而其余基因型为中抗种质.     

Differences in root and shoot growth and soil moisture extraction between cotton cultivars in an acid subsoil

Research was conducted to determine if differences in yield and crop growth of field-grown cotton cultivars (Stoneville 825, Deltapine 41, Auburn 56, and Pima S-5) would be related to root length density and end-of-season soil moisture content in an acid soil. Soil core root density differences between cultivars were inconsistent between years. However, normalization of root density on a percentage of total root density basis indicated Stoneville 825 and Pima S-5 had a consistently greater percentage of roots in the acidic subsoil than did Auburn 56 and Deltapine 41. Subsoil moisture remaining at the end of the season was least for Stoneville 825 and greatest for Deltapine 41. Shoot growth parameters of Stoneville 825 were numerically and often significantly greater than Deltapine 41 each year. Auburn 56 was comparable or superior to Stoneville 825 and Pima S-5 in most parameters of shoot growth. Cotton cultivar differences in root length density and implied soil moisture extraction in acidic subsoil may partly explain differences in adaptation by some cultivars to nonirrigated, drought prone, acidic soils.     

胡麻种质萌发期抗旱性综合评价

为研究不同类型胡麻种质萌发期抗旱性表现,以筛选抗旱品种,为抗旱育种提供科技支撑。本研究采用不同浓度的PEG-6000高渗溶液模拟干旱胁迫的方法,对定亚17、陇亚8号和2011621080进行渗透胁迫试验,筛选适宜浓度的PEG-6000溶液。对161份不同类型的胡麻种质在萌发期进行渗透胁迫试验,考查与抗旱性相关的5个性状,并运用单项抗旱系数、综合抗旱系数、隶属函数和灰色关联度相结合的方法对种质资源的抗旱性进行综合评价。结果表明,不同浓度PEG-6000胁迫对胡麻种质的萌发均有影响,当PEG-6000的浓度在18%时,各种指标的抑制作用均显著加强,因此本研究选用18%的PEG-6000浓度模拟干旱胁迫试验;PEG-6000胁迫降低了161份胡麻种质资源的相对发芽率,抑制了幼芽的生长,种质间表现出较大差异。根据抗旱性量度值将供试种质划为5级,其中1级抗旱型2份、2级15份、3级28份、4级82份、5级34份;供试种质的抗旱性强弱与地理来源息息相关。试验结果说明选择多个性状,综合评价胡麻萌发期抗旱性是可行且准确的。     

薏苡种质资源萌发期抗旱性鉴定及抗旱指标筛选

干旱是影响薏苡生产的主要因素之一,鉴定薏苡种质资源的抗旱性,筛选抗旱指标,培育抗旱品种,对薏苡产业的发展具有重要意义。本研究首先以抗旱性不同的6份薏苡种质为材料,通过调查5个不同浓度的PEG-6000水溶液模拟干旱胁迫下的发芽率,确定了薏苡萌发期模拟干旱胁迫的最适PEG-6000水溶液渗透势为-0.1 MPa。然后以-0.1 MPa的PEG-6000水溶液模拟干旱胁迫,探讨50份薏苡种质发芽势、发芽率、萌发指数、芽长、芽粗、芽鲜重、芽干重、根长、根粗、根鲜重和根干重的变化,利用综合评价法对50份薏苡种质进行萌发期抗旱性鉴定及抗旱指标筛选。结果表明,干旱胁迫对薏苡萌发期各指标均有极显著影响。筛选出萌发期抗旱性强的薏苡种质分别为yy18-1、yy14-3和yy13-1,可为薏苡抗旱育种、抗旱机理及干旱调控缓解机制的研究提供基础材料。芽长、芽干重、根长、根鲜重和根干重可作为薏苡种质资源萌发期简单、直观的抗旱性评价指标。     

Effects of drought stress on seed germination of ornamental sunflowers

The response to drought stress on germination was investigated on three hybrids of ornamental sunflower, ‘Hadar’, ‘Pazit’, and ‘Zohar’. Different levels of water potential [Ψ: 0.0 (control), ?0.15, ?0.30, ?0.45, ?0.60, ?0.75, and ?0.90 MPa] were adopted using polyethylene glycol-6000 (PEG6000) at four germination temperatures (15, 20, 25, and 30 °C). Final germination percentage, mean germination time, germination index, germination rate index, and germination stress tolerance index were used to evaluate the genotype response to PEG-induced water stress. Shoot and root length and fresh and dry weight were measured on seeds germinated at 20 °C under the different levels of water potentials. During germination, the three ornamental sunflowers showed to be more sensitive to suboptimal temperature than to supraoptimal. Decreasing water potential of imbibition solution progressively inhibited and delayed seed germination. Among cultivars, ‘Hadar’ and ‘Pazit’ performed better at temperature lower than 30 °C. ‘Zohar’ showed a lower sensitivity to PEG-induced water stress at all temperature conditions. Water stress during seed germination depressed the following seedling growth under favourable conditions. As a result, shoot and root length and fresh and dry weight was significantly lower in seedlings from seed germinated at ψ ≤ 0.45 MPa.     

Influence of gibberellic acid and different salt concentrations on germination percentage and physiological parameters of oat cultivars

Gibberellic acid (GA₃) is one of the plant growth regulators which improve salt tolerance and mitigate the salt stress impact on plants. The extant analysis was carried out to study the effect of GA₃ and different salt concentrations on seed germination and physiological parameters of oat cultivars. Oats is substantially less tolerant to salt than wheat and barley. Experimentation was conducted as factorial with Completely Randomized Block Design with three replicates. Different concentration of NaCl salt ((25, 50, 75 and 100 mM) were used in test control group and 100 and 150 ppm of GA₃ were used in two group by pre-treated (after 24 h of the seed soaking) and plants were analyzed on 15th day. Results indicate that increasing salinity would decrease the germination percentage and growth parameter in three oat cultivars. Quotes data indicating a 13%, 19.9% and 32.48% in cultivars NDO-2, UPO-212 and UPO-94 germination reduction when soil salinity reaches 50 mM. A 36.02%, 47.33% and 56.365 reduction in germination is likely when soil salinity reaches 100 mM respectively same cultivars. Seeds treated with GA₃ significantly promoted the percentage of germination, shoot and root length, total fresh and dry weight of seedling, tissue water content and seedling vigor index by NDO-2 and UPO-212 under different saline concentration. The maximum average of germination and growth parameters were observed from 150 ppm GA₃ treated seeds. But this concentration was significantly inhibited root length in sensitive cultivar UPO-94 at 75 and 100 mM salt as compared to 100 ppm. We observed that, the high concentration of GA₃ was not suitable for sensitive oat cultivars. Because the plant root are the real workforce behind any plants success. Thus, it may be concluding that, GA₃ treatment could curtail the toxic effect of salinity by increasing germination percentage and shoot and root length, total fresh and dry weight, tissue water content and seedling vigor index in tolerant cultivar.     

Effect of laser pretreatment on germination and membrane lipid peroxidation of Chinese pine seeds under drought stress

The germination of laser-irradiated Chinese pine seeds was carried out under drought stress. The activities of superoxide dismutase (SOD) and peroxidase (POD), and the content of malondialdehyde (MDA) were determined. Results showed notably increased germination percentage, root length, vitality index and fresh weight. The SOD and POD protective enzyme system activity of the Chinese pine seedlings obviously rose. It can be concluded that the germination and juvenile resistance of Chinese pine seeds under drought stress are enhanced after laser processing. Translated from Journal of Shaanxi Normal University (Natural Science Edition), 2006, 34(2): 40–43 [译自: 陕西师范大学学报 (自然科学版)]     

Seed vigour contributes to yield improvement in dry direct‐seeded rainfed lowland rice

Dry direct‐seeded rice (DSR) cultivation is widely spreading in tropical Asia, but drought and nutrient deficiency stresses often cause crop failure in rainfed lowlands. The objective of this study was to dissect the physio‐morphological characteristics associated with crop establishment and early vigour of DSR under drought and P deficiency conditions in the Philippines. It was found that new drought‐resistant cultivars bred for DSR (Rc348 and Rc192) had faster germination and sprout growth than popular irrigated rice cultivars (Rc222 and Rc10) under soil water deficit due to rapid moisture acquisition by the germinating seeds from drying soils. There was a significant correlation between seed moisture content and the reduction in seed dry weight, and between reduction in seed dry weight and shoot elongation under both control and drought stress treatments at the germination stage. At the seedling stage, the root growth of Rc348 under drought tended to be more vigorous with its higher root‐to‐shoot ratio compared to Rc222 and Rc10. The seedling vigour of Rc348 under P deficiency was also greater than that of Rc222 due to its greater root growth and P uptake. The yields of Rc348 and Rc192 grown under rainfed condition at the target drought‐prone site where a dry spell of 13 days occurred during crop establishment were higher (4.0–4.1 t ha^?1) than the yield of Rc10 (3.0 t ha^?1). These results suggest that quick germination and seedling vigour with quick root anchorage and great nutrient uptake capacity, even with limitations of soil moisture and nutrients, would be important traits for DSR in rainfed lowlands.     

Impact of osmotic stress on physiological and biochemical characteristics in drought-susceptible and drought-resistant wheat genotypes

In this study, the seedlings of two wheat cultivars were used: drought-resistant Chinese Spring (CS) and drought-susceptible (SQ1). Seedlings were subjected to osmotic stress in order to assess the differences in response to drought stress between resistant and susceptible genotype. The aim of the experiment was to evaluate the changes in physiological and biochemical characteristics and to establish the optimum osmotic stress level in which differences in drought resistance between the genotypes could be revealed. Plants were subjected to osmotic stress by supplementing the root medium with three concentrations of PEG 6000. Seedlings were grown for 21 days in control conditions and then the plants were subjected to osmotic stress for 7 days by supplementing the root medium with three concentrations of PEG 6000 (D1, D2, D3) applied in two steps: during the first 3 days of treatment ?0.50, ?0.75 and ?1.00 and next ?0.75, ?1.25 and ?1.5 MPa, respectively. Measurements of gas exchange parameters, chlorophyll content, height of seedlings, length of root, leaf and root water content, leaf osmotic potential, lipid peroxidation, and contents of soluble carbohydrates and proline were taken. The results highlighted statistically significant differences in most traits for treatment D2 and emphasized that these conditions were optimum for expressing differences in the responses to osmotic stress between SQ1 and CS wheat genotypes. The level of osmotic stress defined in this study as most suitable for differentiating drought resistance of wheat genotypes will be used in further research for genetic characterization of this trait in wheat through QTL analysis of mapping population of doubled haploid lines derived from CS and SQ1.     

东乡野生稻回交重组系的抗旱性评价体系

选用协青早B//东乡野生稻/协青早B回交重组系及其亲本共79份水稻材料,研究了水稻发芽期、苗期、孕穗期、成熟期的种子萌发抗旱指数等31个指标与东乡野生稻回交重组系抗旱性的关系.结果表明:15％ PEG-6000溶液处理的相对发芽势、20％ PEG-6000溶液处理的种子萌发抗旱指数和相对发芽势及水分胁迫后最长根长、苗高、根鲜质量、根干质量、根系相对含水量、萎蔫率、叶片可溶性糖含量、叶片脯氨酸含量、叶片丙二醛含量、叶片相对含水量、卷叶级别、株高、单株分蘖数、单株有效穗数、穗实粒数、着粒密度、结实率、千粒重等21个指标的相对值与抗旱系数或抗旱指数的相关性显著.通过逐步回归分析筛选出9个抗旱性鉴定指标:20％ PEG-6000溶液处理的相对发芽势及水分胁迫后根干质量、根系相对含水量、叶片可溶性糖含量、叶片脯氨酸含量、叶片丙二醛含量、单株有效穗、结实率和千粒重的相对值.根据这些指标和偏相关系数,建立了不同时期的抗旱性评价(D值)方程和评价体系,可对东乡野生稻回交重组系抗旱性进行较好的评价.