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1.
Priming offers an effective means for counteracting different stresses induced oxidative injury and raising seed performance in many crop species. The present study was carried out to investigate the ability of potassium nitrate (KNO3) and urea to promote the tolerance of different maize hybrids to drought and salt stresses to identify some biochemical parameters associated with KNO3 and urea induced resistance in maize seedlings. An experiment was conducted in a controlled environment of the laboratory at the college of agriculture, Shiraz University, Shiraz Iran, during 2010. The first factor was stress type and intensity at five levels; moderate drought, severe drought, moderate salt, severe salt, and control (without stress). Seed priming was the second factor; water as control, KNO3, and urea, and maize hybrids, including Maxima, SC704, Zola, and 304 were the third factor. Results indicated that the highest chlorophyll a (Ch a), chlorophyll b (Ch b), total chlorophyll (Ch T) contents, and carotenoids (Car) were found in no stress treatments and the most proline, protein contents, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities in severe drought treatment. Also, results revealed that generally, drought and salinity stresses decreased the amount of Ch a and the lowest Ch a was recorded for severe salinity stress (4.29 mg g?1). Stresses caused decrease in Ch b, but the effect of sever salinity level was higher than the others. Priming of KNO3 had significantly higher proline content than water and urea priming. The SC704 and 304 hybrids showed higher proline content than the other ones. Finally, the maize seed KNO3 and urea priming lead to high activities of antioxidant defensive enzymes and increase the tolerance level to abiotic stresses such as salt and drought.  相似文献   

2.
复水对海水浇灌的玉米幼苗根系补偿效应的影响   总被引:1,自引:1,他引:0  
为了在沿海地区利用海水补充浇灌技术实现作物的安全节水灌溉,从而节约农业用水,以抗性玉米品种"农大108"为材料,研究了先用不同浓度海水处理组分别浇灌玉米幼苗,再用清水浇灌,然后用聚乙二醇(PEG-6000)模拟干旱胁迫的过程中根系补偿特性的变化。结果表明,复水前25%海水持续浇灌组和25%海水和50%海水交替浇灌组处理中,根系脯氨酸含量及超氧物歧化酶活性明显增加,可溶性糖及K+含量、根系活性及相对含水率、根冠比缓慢上升,丙二醛含量减少;复水后,根系K+含量、根系活性及相对含水率明显上升,而其他指标呈现下降的趋势;干旱模拟期间,根系活性及丙二醛含量略微下降,其他指标急剧升高。与清水灌溉组相比,50%海水持续胁迫对根系造成损伤使得复水补偿代谢显著降低,25%海水持续浇灌组的补偿能力略微下降,25%海水和50%海水交替浇灌组复水补偿效应略微或明显增强。因此,经过适宜浓度的海水胁迫诱导后,根系发生适应性代谢,然后复水,根系的物质代谢及抗旱性可以产生补偿甚至超补偿效应,同时也缓解了盐渍对植物的次生胁迫效应。  相似文献   

3.
Water deficit stress is the main limiting factor in corn production in different regions of Iran. Choosing appropriate corn hybrids and well-managed irrigation practices will result in significant water savings (WS) and good outcomes. Therefore, a randomized complete block design arranged in split plots with four replications was used to evaluate the effect of irrigation regimes on some agronomic traits of corn hybrids. Three different irrigation regimes (irrigation after depleting 60%, 70%, and 80% of field capacity (FC) as water deficit stress, mild water deficit stress and well-irrigated treatment, respectively) were allocated to main plots and four grain corn hybrids (KSC 500, KSC 647, KSC 700, and KSC 704) were randomized in subplots. The results indicated that grain yield (GY), harvest index (HI), and relative water content (RWC) decreased, whereas water use efficiency (WUE), WS, and irrigation efficiency (IE) increased, with increasing water deficit stress intensity. Irrigation after depleting 70% of FC caused the highest economic WUE (1.01 kg grain m?3). In addition, late maturing hybrids (KSC 700 and KSC 704) showed higher values of all measured traits, except for HI, compared to mid-maturing hybrids (KSC 647 and KSC 500).  相似文献   

4.
以辣椒为研究对象,研究了不同光照强度和土壤水分对辣椒叶片相对含水率(RWC)、叶绿素(Chl)含量、保护酶活性以及游离脯氨酸和丙二醛(MDA)含量的影响。结果表明:1)随着遮阴程度和土壤水分的增加,叶片RWC,叶绿素含量均呈上升趋势,土壤水分增加主要有利于叶绿素a含量的增加,遮阴主要有利于叶绿素b含量的增加。类胡萝卜素含量随遮阴程度的增加和土壤水分的降低而下降。MDA含量在干旱胁迫条件下升高,随着遮阴程度的增加呈先降后升的趋势。光照相同,在干旱和高水条件下,保护酶活性和脯氨酸含量均表现出不同程度的上升;水分条件相同,保护酶活性和脯氨酸含量均随遮阴程度的增加而下降,且保护酶对光照强度的敏感性为SOD>CAT>POD。2)保护类物质(脯氨酸与保护酶)与伤害类物质(MDA)均达到了极显著正相关,膜保护酶与叶绿素含量达到了极显著负相关。综合以上认为,将遮阴30%和土壤相对含水率为70%~85%作为适宜的遮阴和灌溉指标是科学合理的。  相似文献   

5.
土壤含水量对狗牙根叶片生理生态指标的影响   总被引:1,自引:1,他引:1  
采用盆栽控水试验,研究了不同土壤含水量(水淹,23%,18%,13%,8%)对我国雅砻江库区重要植物物种狗牙根叶片光合色素、SOD活性、POD活性、脯氨酸和MDA含量变化的影响。结果表明:与对照(23%)相比,狗牙根受到淹水胁迫时叶绿素a,b的含量和光合效率有所下降,丙二醛含量有所升高,但是抗氧化酶活性以及脯氨酸含量的增大提高了植物对淹水胁迫的抵抗力。随着土壤含水量的减少,叶绿素a和b的含量、光合速率、SOD、POD活性和丙二醛含量先升高,随后逐渐降低。SOD和POD活性在8%时存在最低值,分别为33.10U/gFW和3.87U/gFW。Carotenoid/Chlorophyll(Car/Chl)比值在18%时达到最低值0.22,然后增大。脯氨酸(Pro)含量随胁迫程度呈明显的增大趋势,并在8%达到最大值0.31μg/gFW,说明干旱条件时狗牙根通过提高类胡萝卜素和脯氨酸含量来改善渗透调节能力,增强对干旱胁迫的抵抗能力和适应力。但严重的干旱胁迫(8%)导致了植物叶片的损伤。  相似文献   

6.
通过盆栽进行春玉米控水试验,设置3个控水水平(正常供水、中度干旱、重度干旱)、2个水分控制时段(干旱、复水),研究苗期不同程度干旱胁迫及复水对春玉米叶片光响应曲线、CO2响应曲线及曲线拟合参数和抗氧化酶活性的影响。结果表明:干旱胁迫条件下春玉米叶片对光辐射的利用能力下降,随着干旱胁迫程度增加,叶片最大净光合速率(Pnmax)、表观量子效率(AQY)、光饱和点(LSP)、最大电子传递速率(Jmax)、最大羧化速率(VCmax)均显著下降,而光补偿点(LCP)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均显著升高。复水后,前期中度干旱处理条件下玉米叶片Pnmax、AQY、LSP、Jmax、VCmax均高于一直正常供水水平和中度干旱水平;而前期重度干旱处理的上述各参数(Jmax、VCmax除外)均未达到一直正常供水水平,但高于重度干旱水平。SOD、POD和CAT活性均有所下降,但仍高于一直正常供水水平和干旱水平,而重度干旱后复水则下降幅度较小。苗期中度干旱锻炼具高抗氧化酶活性清除活性氧,使得膜脂过氧化程度轻,复水后其膜容易修复,使叶片光合效率产生超补偿效应,而重度干旱后复水其膜修复滞缓,使光合效率产生部分补偿效应。因此,在西北旱区春玉米生产实践中,如果进行抗旱锻炼,应限制在中度干旱水平,避免重度干旱。  相似文献   

7.
A short-term experiment was carried out to study the effects of exogenous nitric oxide (NO) on some growth parameters and mineral nutrients of maize grown at high zinc (Zn). Maize seedlings were planted in pots containing perlite and subjected to 0.05 or 0.5 mM Zn in nutrient solution. Nitric oxide (0.1 mM) was sprayed to the leaves of maize seedlings. High Zn reduced total dry matter, chlorophyll (Chl.) content and leaf relative water content (RWC), but increased proline content and membrane permeability. Foliar application of NO significantly increased chlorophyll content, RWC and growth of plants treated with high Zn, and significantly reduced their membrane permeability and proline contents. High Zn resulted in increased leaf and root Zn, but lower concentrations of leaf phosphorus (P), and iron (Fe). Foliar application of NO lowered leaf and root Zn and increased leaf and root nitrogen (N) and leaf Fe in the high Zn plants. These results clearly demonstrated that externally-applied NO induced growth improvement in maize plants was found to be associated with reduced membrane permeability under high zinc. Results can be concluded that NO may be involved in nutritional and physiological changes in plants subjected to high Zn.  相似文献   

8.
砧木的抗旱能力直接影响桃品种生长发育,选择适宜抗旱性桃砧木对桃产业发展有积极的促进作用。为阐明不同桃砧木对干旱胁迫生理响应机制,以5种桃砧木扦插苗为试材,通过盆栽控水方式,研究不同程度干旱胁迫下5种桃自根砧的叶片水分特性、渗透调节物质、抗氧化物酶及叶绿素含量变化。结果表明,随着干旱程度加重,5种砧木相对含水量、临界含水量下降,自然饱和亏、临界饱和亏及需水程度上升,组织密度和自由水含量逐渐减少,束缚水含量则增大,持水能力、组织水势和耐旱系数下降。各干旱胁迫处理的丙二醛(MDA)含量、 游离脯氨酸(Pro)含量、可溶性糖含量和叶绿素含量均增加;过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性提高,其中随干旱程度加重,丙二醛(MDA)含量、游离脯氨酸(Pro)含量均呈增加趋势,SOD活性、CAT活性也均呈提升趋势,可溶性糖含量、叶绿素含量、POD活性变化不尽相同。综合隶属函数分析可知,桃自根砧品种间抗旱性由强到弱依次为樱桃李5号、RA、樱桃李3号、GF677、樱桃李1号。  相似文献   

9.
10.
An experiment was conducted to assess whether accumulation of photosynthetic pigments, proline, and maintenance of water relation attributes relate to the yield of maize hybrids differing in salt tolerance. Two maize hybrids, Pioneer32B33 and Dekalb979, were grown at three salinity levels under four nitrogen treatments. The experiment was laid out in a three-factor randomized complete block design and there were three replications of each treatment. Salt stress significantly decreased leaf chlorophyll a and a/b contents, whereas chlorophyll b and total chlorophyll were slightly increased. Under salinity stress, relative water content decreased, and water potential and osmotic potential become more negative. As a result, turgor potential also decreased. Nitrogen application improved all the chlorophyll pigments, water-related attributes, and yield components. However, chlorophyll a/b ratio was decreased. Overall, because of the differential response of maize hybrids to salt stress in terms of their performance in photosynthetic pigments, water relations, and yield, it can be concluded that hybrid Pioneer32B33 might perform better, if grown under salinity regime and sufficient nitrogen was applied in the growth medium.  相似文献   

11.
Abstract: Understanding plant responses to drought stress is essential, and there is a need to know possible physiological mechanisms of damage and drought avoidance for the genetic improvement of crops. Therefore, we investigated the effects of silicon (Si) on shoot and root growth, leaf relative water content (RWC), stomatal resistance (SR), lipid peroxidation (MDA), membrane permeability (MP), proline and hydrogen peroxide (H2O2) accumulation, nonenzymatic antioxidant activity, and the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) of 12 sunflower cultivars grown under drought conditions. Silicon applied to the soil counteracted the deleterious effects of drought in 6 of the 12 sunflower cultivars. In general, SR and H2O2, proline, and MDA content were increased in all the cultivars under drought stress. However, application of Si decreased their levels and alleviated membrane damage (MP) significantly by increasing leaf RWC. The CAT activity was significantly decreased by drought stress, but supplemental Si increased it. In general, SOD and APX activities of the cultivars were increased by drought and decreased by application of Si. The nonenzymatic antioxidant activity of the cultivars was significantly increased by Si under drought stress. Based on the present work, it can be concluded that applied Si alleviates drought stress in sunflower cultivars by preventing membrane damage, although the cultivars showed genotypic variation in response to applied Si.  相似文献   

12.
ABSTRACT

Drought tolerance is a complex trait that involves different biochemical and physiological mechanisms in plants. It was the objective of the present study to evaluate the agronomic and biochemical responses of triticale, tritipyrum, and wheat to drought stress. For this purpose, twenty-seven genotypes were evaluated under two levels (non-stress and drought stress) of irrigation during 2015?2017. The metabolic traits studied included relative water content (RWC), membrane stability index (MSI), chlorophyll a (Chla), chlorophyll b (Chlb), carotenoids (Car), leaf proline content (Pro), leaf soluble carbohydrates (LSC), glycine betaine (GB), malondialdehyde (MDA), hydrogen peroxide (H2O2), seeds per spike (SS), seed weight (SW), biological yield (BY) and seed yield (SY). Drought stress increased Pro, LSC, and GB contents as well as lipid peroxidation through increasing MDA and H2O2 activities. However, both RWC and MSI indices as well as SS, SW, SY and BY reduced as a result of drought treatment although the least decrease of SY was observed at triticale group. During the two years of study, the tritipyrum genotypes exhibited their drought tolerance by accumulation of more LSC and GB as well as lower decrease in SW while the triticale ones responded by maintaining higher levels of RWC but producing less MDA and H2O2. It may, therefore, be concluded that the three species studied exploit different mechanisms to maintain tolerance against drought stress. Finally, correlation analysis indicated the positive effects of LSC on SY under both drought and normal conditions, which is obviously a promising trait in wheat, triticale, and tritipyrum that can be beneficially exploited in drought tolerance improvement programs.  相似文献   

13.
Two contrasting maize (Zea mays L.) cultivars, i.e. ‘Shaandan 9’ (S9) and ‘Shaandan 911’(S911) were investigated by examining foliar nitrogen (N) modulation of N metabolism, water status and plant growth under short-term moderate water stress (SMWS). On 10th day of SMWS, dry matter (DM), relative water content (RWC) and nitrate reductase activity (NRA) were significantly decreased, whereas concentrations of free proline (FP), glycinebetaine (GB) and soluble protein (SP) were increased in leaves of both cultivars. Cultivar S9 maintained greater DM, RWC and these N metabolism traits than S911 during SMWS. Foliar N application much more raised DM, RWC, NRA, and concentrations of all solutes measured under SMWS above control. These positive effects were more pronounced in S911 than those in S9 during SMWS. Greater correlations were performed amongst all parameters under SMWS than control. Hence, we suggest that foliar N should be firstly applied to drought sensitive cultivars under drought.  相似文献   

14.
The effects of exogenous silicon (Si) on key growth parameters and mineral nutrients were investigated in maize grown at high zinc (Zn). Four treatments with three replicates were investigated consisting of a control (basal nutrients with 0.05 mM Zn with or without 1.0 mM Si added), 0.5 mM Zn, and 0.5 mM Zn plus 1.0 mM Si. Plants growing with high Zn alone had a lower chlorophyll (Chl.) content, leaf relative water content (RWC) and produced less biomass than the control plants. Proline content and membrane permeability was higher in zinc-treated plants than in untreated controls. Compared with the plants treated with high Zn alone, added Si significantly increased plant growth, chlorophyll content, and RWC and significantly reduced the membrane permeability and proline content. As expected, added high Zn increased leaf and root Zn, but reduced leaf phosphorus (P) and iron (Fe). Added Si reduced Zn concentration and increased Fe in leaves of maize. It can be concluded that improvement in the key growth parameters tested and mineral nutrition status in maize plants grown at high Zn induced by Si addition may protect membrane permeability under high zinc, thus mitigating Zn toxicity and improving the growth of maize plants. The results of the present experiment support the conclusion that Si may be involved in physiological and nutritional changes in plants grown at high Zn.  相似文献   

15.
为探明干旱胁迫及复水条件下不同剂量草甘膦对抗草甘膦大豆(RR1)幼苗叶片渗透调节物质、莽草酸(shikimic acid, SA)含量及根系活力的影响,采用盆栽试验,在大豆的第3复叶期进行水分胁迫5d和除草剂草甘膦处理,研究RR1幼苗叶片可溶性蛋白(soluble protein, SP)、可溶性糖(soluble sugar, SS)、游离脯氨酸(free praline, FP)、莽草酸(shikimic acid, SA)含量和根系活力(RA)的变化。结果表明,干旱胁迫前期RR1叶片的SP含量随草甘膦剂量的增加呈先升高后降低趋势,0.46kg/hm2叶片SP的含量最高,胁迫后期SP含量随草甘膦剂量的增加而降低;SS、FP和SA含量随草甘膦剂量的增加和胁迫时间的延长而增加,RA随草甘膦剂量的增加和胁迫时间的延长而降低。复水12d后,不同剂量草甘膦处理的各指标均有所恢复。干旱条件下,经草甘膦处理的RR1叶片的SP含量和RA低于草甘膦在正常水分条件下的处理,而SS、FP和SA含量相反。相关性分析表明,FP和SA含量与草甘膦剂量的相关关系最明显;而SS和SA含量与干旱胁迫时间的相关关系最明显。说明正常水分条件下,草甘膦对RR1幼苗造成的伤害经过一段时间后有所缓解;干旱胁迫加剧了草甘膦对RR1幼苗叶片渗透调节物质、莽草酸含量和根系活力的影响。抗草甘膦大豆主要通过积累FP、SS和SA对草甘膦和干旱胁迫做出响应。  相似文献   

16.
A simulation experiment on the responses of maize (Zea mays L.) from the third leaf stage to maturity for different soil water levels (well-watered, moderately stressed, and severely stressed) was conducted by controlling irrigation and using a mobile rain shelter in a neutral loam, meadow soil to determine the effects on leaf water status, membrane permeability and enzymatic antioxidant system for different growth stages. The results indicated that drought stress relied on drought intensity and duration, with more severe drought stress creating more serious effects on maize. Compared with wellwatered conditions, during the silking and blister stages moderate stress did not significantly change the relative water content (RWC) and did change significantly the relative conductivity (RC) (P 〈 0.05) of the leaves; however, severe stress did significantly decrease (P 〈 0.01) the leaf RWC and increase (P 〈 0.01) membrane permeability (leaf relative conductivity). Furthermore, under severe drought stress antioxidant enzyme activities declined significantly (P 〈 0.01) in later stages, namely for superoxide dismutase (SOD) the tasseling and blister stages, for peroxidase (POD) the milk stage, and for catalase (CAT) during the tasseling, blister, and milk stages. Meanwhile, membrane lipid peroxidation (measured as malondialdehyde content) significantly increased (P 〈 0.01) in all stages.  相似文献   

17.
Among various abiotic stresses, global drought reduces global growth and yield of wheat. Present research has been designed to ameliorate the adverse effects of drought stress on wheat by combined application of plant growth-promoting rhizobacteria (PGPR), compost, and mineral fertilizers. In this experiment, the role of fertilizer, compost, and PGPR inoculation to ameliorate drought stress was studied in two wheat varieties at vegetative stage. Water stress adversely affects morphology, physiology, and biochemistry of the wheat plant. Inoculated seed with compost and mineral fertilizer grown in drought condition showed 43% increase in relative water content (RWC) of 9.39% in Membrane Stability Index and 82.20% in chlorophyll as compared to control. Drought affected the accumulation of osmolytes, but PGPR in combination with compost and mineral fertilizer under drought stress triggered higher accumulation of soluble sugar and proline content, i.e., 28.96% and 73.91%, respectively. It is concluded from this research that PGPR in combination with compost and mineral fertilizer considerably reduces the effect of drought on wheat by enhancing the physiological (RWC, membrane stability, chlorophyll content, and water potential) and biochemical (proline and sugar) aspects of the plant.  相似文献   

18.
Two field experiments were executed to investigate the effects of foliar-applied moringa (Moringa oleifera) leaf extract (MLE; 1:30 w/v) and salicylic acid (SA; 0.5 mmol), singly or in combination, on growth, physio-biochemical, yield attributes and water use efficiency (WUE) of maize (Zea mays L., Three Ways Cross 329) under full and deficit irrigation conditions. Deficit irrigation was carried out by withholding water for 36 d from 12 to 48 days after sowing (DAS). At vegetative stage, deficit irrigation signi?cantly decreased all growth criteria, chlorophyll a concentration, and relative water content (RWC). In contrast, deficit irrigation considerably increased the concentrations of carotenoids, proline, membrane permeability (MP) and malondialdehyde (MDA). Similarly, grain yield, most yield components and WUE were significantly depressed in drought-stressed plants. However, foliar-applied treatments particularly MLE+SA signi?cantly increased growth traits, photosynthetic pigments, RWC and proline accumulation associated with a simultaneous decrease in MP and MDA concentration under full and deficit irrigation conditions. The application of MLE+SA markedly increased grain yield, yield components and WUE over control (spray tap water). Overall, the combined application of MLE and SA could be used for alleviating the adverse effects of growth, physiology, yield criteria and WUE in drought-stressed maize plants.  相似文献   

19.
采用称量控水方法,设置正常供水(CK)、轻度干旱胁迫(LD)、中度干旱胁迫(MD)和重度干旱胁迫(SD)4种水分处理,研究不同程度干旱胁迫对1年生台湾栾树盆栽苗生长和生理生化指标的影响,探讨台湾栾树耐旱机制.研究发现:随干旱胁迫程度的加剧,台湾栾树幼苗高生长量和生物量逐渐降低,但根冠比显著提高;台湾栾树幼苗叶丙二醛浓度、可溶性糖及脯氨酸质量分数增加,K+和Ca2质量分数在LD处理略有升高后缓慢下降,Mg2+质量分数则只有轻微减少;而叶可溶性蛋白质质量分数及CAT、POD、SOD、APX等活性表现为先增加后降低的规律,且在MD处理均达到最大.结果表明:干旱胁迫下台湾栾树膜脂过氧化加剧和生长受到抑制,但其能通过提高抗氧化酶系统的活性和积累可溶性糖、脯氨酸及可溶性蛋白质等渗透调节物质来保护膜结构,使其保持正常的生理活动,从而表现出较强的抗旱能力.  相似文献   

20.
干旱胁迫条件下加工番茄对喷施甜菜碱的生理响应   总被引:4,自引:1,他引:3  
以新疆广泛种植的加工番茄屯河8号为材料,通过盆栽和田间试验,测定了加工番茄叶片中叶绿素、可溶性蛋白、脯氨酸、可溶性糖和丙二醛含量以及抗氧化酶 [超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)] 活性和加工番茄产量,研究了干旱胁迫下加工番茄对叶面喷施不同浓度甜菜碱的生理响应。结果表明,干旱胁迫下喷施低浓度甜菜碱对加工番茄抵御干旱有一定的作用。干旱胁迫下喷施甜菜碱后,有效抑制了叶绿素和可溶性蛋白含量的下降,协同增加脯氨酸和可溶性糖的含量,抗氧化酶活性也显著增强,膜脂过氧化程度减弱即丙二醛含量下降,田间试验各生理指标的含量变化与盆栽结果相类似,干旱胁迫下喷施甜菜碱促进了加工番茄产量的增加。  相似文献   

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