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1.
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   

2.
福寿螺(Pomacea canaliculata)是首批列入我国外来入侵物种黑名单的生物。本文采用干旱后复水方式喂养福寿螺48 d,研究间歇性干旱处理下福寿螺摄食生长、肝胰脏抗氧化能力及胃消化酶活力变化。结果显示:间歇性干旱能够显著降低福寿螺的体重增长率,对存活率影响不明显;福寿螺在恢复摄食期间出现部分补偿生长现象,主要是通过复水后增大摄食量来实现的,当间歇性干旱时间间隔延长到8 d时,则是通过增大摄食量和提高食物转化率的双重作用来实现的;除间隔4 d间歇性干旱下SOD酶活力以外,福寿螺在短间隔(1~4 d)间歇性干旱下SOD和CAT活力均出现不同程度的增加,而MDA含量明显降低;在长间隔(8 d)间歇性干旱下,SOD和CAT活力均低于对照组,且MDA含量与对照组无差别;间歇性干旱降低了福寿螺肝胰脏中GST和GSH-PX活性,对GSH含量无明显影响;除间隔1 d的处理组胃脂肪酶外,间歇性干旱能够不同程度地提高福寿螺胃淀粉酶和胃脂肪酶活力。总体而言,在间歇性干旱胁迫下,福寿螺可通过提高摄食率、食物转化率、抗氧化能力、消化酶活性等,在一定程度上来缓解胁迫带来的影响,但间歇性干旱能够明显抑制福寿螺的正常生长,表明通过农田水位交替性变化可在一定程度上防控福寿螺的暴发与危害。  相似文献   

3.
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   

4.
Cotton (Gossypium hirsutum L.) is a well-known and economically most beneficial crop worldwide while nickel (Ni) toxicity is a widespread problem in crops grown on Ni-contaminated soils. We investigated the response of silicon (Si) in cotton under Ni stress with respect to growth, biomass, gas exchange attributes, enzymatic activities, and Ni uptake and accumulation. For this, plants were grown in hydroponics for 12 weeks with three levels of Ni (0, 50, and 100 µM) in the presence or absence of 1 mM Si. Results showed that Ni significantly reduced the plant growth, biomass, gas exchange attributes, and pigment contents while Si application mitigated these adverse effects under Ni stress. Nickel stress significantly decreased antioxidant enzymes’ activities while increased malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EC) in leaves and roots. The application of Si enhanced the activities of antioxidant enzymes and reduced MDA, H2O2, and EC in plants. Nickel application significantly increased Ni concentration and accumulation in leaf, stem, and roots while Si application significantly decreased Ni in these plant parts. The present study indicates that Si could improve cotton growth under Ni stress by lowering Ni uptake and reactive oxygen species (ROS) and by increasing antioxidant enzymes activities.  相似文献   

5.
In this study, the effects of penconazole (PEN) and calcium (Ca) on growth amelioration and quality of seed oil in canola (Brassica napus L.) under drought stress were investigated. Drought stress reduced the growth parameters (fresh weight and dry weight) in canola; however the application of PEN and Ca improved these parameters under drought condition. Inducing effect of Ca on protein content was more prominent than PEN. Proline content increased under drought stress and PEN and Ca treatment caused more induction it under drought. PEN and Ca alleviated the negative effects of drought stress in canola by inducing antioxidant defense. The application of PEN and Ca caused a significant reduction in lipid peroxidation and hydrogen peroxide and mitigation of the drought induced oxidative stress. Drought stress induced protein content, total phenol, flavonol content, soluble sugar, palmitic acid and palmitoloic acid, and reduced flavonoid content, oleic acid, linolenic acid, and linolonoic acid in canola seed. PEN and Ca increased palmitic acid, linoleic acid (Omega-6), linolenic acid (Omega-3), oleic acid, protein, and soluble sugar. Our results indicated that application of PEN and Ca enables canola plants to withstand the deleterious impact of drought stress and caused improvement of antioxidant capacity, essential fatty acids (linolenic acid and linolonoic acid) and oil quality in canola seed.  相似文献   

6.
Selenium (Se), regarded as an antioxidant, has been found beneficial for plants growing under stressed conditions. To investigate whether the Se application helps to improve stress tolerance, sodium selenite (Na2SeO3 · 5H2O, 5–15 μM) was hydroponically applied to Zea mays variety OSSK-713-roots under heat and/or PEG-induced osmotic stress (25% PEG-6000) for 8 h. The individual/combined stress caused accumulation of reactive oxygen species (ROS). While only superoxide dismutase (SOD) increased with heat stress alone, the activities of SOD, catalase (CAT) and ascorbate peroxidase (APX) increased under PEG exposure. The combination of these stresses resulted in an induction of both SOD and CAT activities. Lipid peroxidation (TBARS) levels were also high in all the stress treatments, especially under the combination treatment. Addition of Se not only improved the activities of SOD, APX and glutathione reductase (GR) in stress-treated roots, but it also changed the activities of monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR). The findings reveal that Se has a positive effect on heat and/or osmotic stress mitigation mainly by regulating the ascorbate-glutathione cycle, especially in PEG-treated plants. Under the combined stress treatment, addition of 5 µM of exogenous Se was most effective.  相似文献   

7.
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   

8.
Role of exogenously-applied silicon (Si) on antioxidant enzyme activities was investigated in wheat under drought stress using a completely randomized factorial design with four replications. Drought stress significantly enhanced activities of ascorbate peroxidase, peroxidase, superoxide dismutase and catalase, and elevated accumulation of osmotically active molecules, soluble sugars and proline. Si application further enhanced activities of enzymes involved in oxidative defense system and accumulation of osmotically active molecules in drought-stressed plants. Under drought stress conditions, water shortage decreased protein content in all cultivars; however, application of Si increased it. Pollen area ratio was lower than 1 for cvs. Shiraz and Marvdasht under drought, but greater than 1 for cvs. Chamran and Sirvan. Water-limited regimes resulted in decreased leaf Ψw in all cultivars, but Si supply was effective in improving Ψw under water-limited regimes. Water shortage increased leaf K, Mg, and Ca concentrations. Under drought stress, Si-treated plants had higher K concentration than the none-treated plants.  相似文献   

9.
烟草是重要的模式植物和经济作物,盐害和干旱两种环境因子对其生长发育、产量和品质都危害很大。为了提高烟草的耐盐抗旱性,本研究利用农杆菌介导的遗传转化法在烟草中过量表达了碱蓬液泡膜Na~+/H~+逆向转运基因SsNHX1,对转基因烟草的耐盐及抗旱性进行表型鉴定和各项生化指标的检测,以期得到耐盐抗旱表性良好的SsNHX1转基因烟草。表型分析发现,SsNHX1基因过表达株系L1和L5的抗盐能力比野生型显著提高,表现为盐胁迫条件下仍能保持旺盛的生长且根系的伸长未受抑制。SsNHX1过表达株系在叶片和根系中积累了更多的Na~+和K~+,同时Na~+含量增长速率较快,而K~+含量降低速率较缓,并可维持较高的叶片相对含水量和叶绿素含量,及较低的丙二醛含量和相对电导率。干旱胁迫发现,过表达株系受干旱胁迫程度更小,并在复水后迅速恢复正常生长。同时,过表达株系的丙二醛含量和相对电导率显著低于野生型,且维持了较高的叶片相对含水量及叶绿素含量。这些结果说明SsNHX1基因在烟草中过量表达后,降低了盐胁迫和干旱胁迫对烟草根系及细胞膜的损伤,并通过调节离子含量、降低细胞的渗透势,维持了叶片较高的相对含水量和叶绿素含量,最终提高了烟草的抗盐和抗旱性。  相似文献   

10.
Ameliorative effect of silicon (Si) (2 mM as sodium silicate (Na2SiO3)) was studied in tobacco (Nicotiana rustica L.) plants grown under control at 100% field capacity (FC), mild drought (60% FC), and severe drought (30% FC) conditions. Si-treated plants had higher biomass of particularly above-ground parts both under drought and control conditions. Plants with Si supply had significantly higher net assimilation rates but lower transpiration rates. Silicon supply enhanced osmotic potentials only in the leaves, but not in the roots. A considerable rise in the concentrations of soluble sugars was observed particularly in the leaves under both drought and Si treatments. Soluble proteins, free α-amino acids, and proline concentrations increased in Si-treated plants under all watering treatments. Si enhanced the activity of antioxidative enzymes and decreased hydrogen peroxide (H2O2) concentrations. Results indicate that Si supplementation alleviates drought stress via improvement of water relation parameters, enhancement of photosynthesis, and elevation of antioxidant defenses.  相似文献   

11.
This study aims to explain the effects of silicon (Si) foliar application on gas exchange characteristics, photosynthetic pigments, membrane stability and leaf relative water content of different wheat cultivars in the field under drought stress conditions. The experiment was arranged as a split-split plot based on randomized complete block design with three replications. Irrigation regime (100%, 60%, and 40% F.C.), silicon (control and Si application) and wheat cultivars (Shiraz, Marvdasht, Chamran, and Sirvan) were considered as main, sub and sub-sub plots, respectively. This study was carried out at the Research Farm of the Collage of Agriculture, Shiraz University, Iran, during 2012–2013 growing season. The results showed that foliar application of silicon increased the leaf relative water content, photosynthesis pigments (chlorophyll a, b and total chl and carotenoids), chlorophyll stability index (CSI) and membrane stability index (MSI) in all wheat cultivars, especially in Sirvan and Chamran (drought tolerant cultivars), under both stress and non-stress conditions. However, more improvement was observed under drought stress as compared to the non-stress condition. In contrast, these parameters decreased under drought stress. Si significantly decreased electrolyte leakage in all four cultivars under drought stress conditions. Furthermore, the intercellular carbon dioxide (CO2) concentration (Ci) increased under drought stress. Si application decreased Ci especially under drought stress conditions. Net photosynthesis rate (A), transpiration rate (E) and stomatal conductance (gs) were significantly decreased under drought conditions. Under drought, Si applied plants showed significantly higher leaf photosynthesis rate, transpiration rate, and stomatal conductance. Intrinsic water use efficiency (WUEi) and carboxylation efficiency (CE) decreased in all cultivars under drought stress. However, the silicon-applied plants had greater WUEi and CE under drought stress. The stomatal limitation was found to be higher in stressed plants compared to the control. Exogenously applied silicon also decreased stomatal limitation. Overall, application of Si was found beneficial for improving drought tolerance of wheat plants.  相似文献   

12.
磷脂酶D（phospholipase D,PLD）通过水解细胞膜磷脂产生信使物质磷脂酸（PA）,并介导多种激素与逆境的信号转导过程。为探讨PLD在参与干旱信号转导调控细胞膜稳定性方面的作用及其途径,采用在培养液中加入PEG-6000模拟干旱胁迫,用PLD抑制剂正丁醇（n-butanol,BA）抑制PLD产生PA,对比PEG+BA处理与PEG处理下小麦抗旱性、膜稳定性以及抗氧化酶类的变化。结果表明,与PEG处理相比,PEG+BA处理下,冬小麦幼苗叶片生长受抑制,净光合速率下降,光合非气孔限制作用增强,细胞膜离子渗漏率显著升高,膜脂过氧化产物丙二醛（malonaldehyde,MDA）升高,抗氧化酶POD活性下降,表明PLD参与干旱胁迫下过氧化物酶（peroxidase,POD）活性的调控。由此揭示出一条潜在的由PLD介导的干旱信号转导途径,即干旱胁迫—PLD激活—POD活性增强—保护膜脂过氧化损伤—提高细胞膜稳定性—植物抗旱性增强。  相似文献   

13.
The effects of boron (B) and high irradiance (HI) on the growth and activities of antioxidant enzymes have been investigated in cowpea plants (Vigna unguiculata L. Walp. ‘P152’). A significant decrease in root and shoot lengths were observed in B-deficient (0 ppm) and B-excess (50 ppm) plants compared to B-sufficient (0.5 ppm) plants. Under B and B + HI stress, significant increase in membrane permeability (EC), lipid peroxidation (MDA) and hydrogen peroxide (H2O2) were observed in B-deficient and B-excess leaves. Under B and B + HI stress, the superoxide dismutase (SOD) activity was found to be significantly high whereas the peroxidase (POX), polyphenol oxidase (PPO) activities and the non-enzymatic antioxidants, ascorbic acid and proline accumulation were found to be significantly decreased in B-deficient and B-excess leaves which showed the B inefficiency and susceptible nature of the cowpea plants to B and B + HI stress.  相似文献   

14.
Nitrogenase activity and trehalose accumulation were measured in nodulated and non-nodulated common beans (Phaseolus vulgaris) that were exposed to drought. Plants were infected with the Fix+Rhizobiumsp NGR234, or a Fix− derivative (NGRΩfixF), or high trehalose-producing, native rhizobia. Trehalose content increased significantly while acetylene reduction activity (ARA) decreased in the nodules of plants exposed to drought. Nevertheless, ARA decreased at a slower rate in nodules with high trehalose levels. Under water stress, nodules infected with NGRΩfixF tended to accumulate more trehalose than nodules infected with wild-type NGR234 (9±0.1 vs 8±0.1 mg g−1 dw, respectively). Highest trehalose accumulations were registered in nodules of plants infected with native rhizobia (average 16 mg g−1 dw), and these plants also exhibited the highest relative water content (65%), while in plants infected with the NGRΩfixF RWC was significantly lower (56%). Our results suggest that nodule trehalose may protect bacterial nitrogenase activity under drought conditions, and that both trehalose and biological nitrogen fixation (BNF) contribute to drought tolerance.  相似文献   

15.
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16.
Since studies on the effects of selenium (Se) supplementation in water-stressed plants have mainly focused on cereal crops, the specific reports regarding Se-mediated adaptation to drought stress in medicinal vegetables are scant. Thus, we investigated the responses of Melissa officinalis to Se supplementation. Selenium contents were increased in leaves and grains by supplemental Se. Selenium foliar application at 1 mg l?1 could be useful to increase the vegetative and reproductive growth of Se-enriched plants under well-watered conditions but at 20 mg l?1 led to toxicity and caused damage to shoots. Drought stress significantly inhibited plant growth by chlorophyll degradation and reduced net carbon dioxide (CO2) assimilation rate. Although Se at 1 mg l?1 could increase biomass production under well-watered conditions in addition to the stimulation of antioxidant system under water stress, it could not ameliorate the negative effect of drought on productivity.  相似文献   

17.
We examined the role of jasmonic acid (JA) in faba bean under cadmium (Cd) stress, which reduces the growth, biomass yield, leaf relative water content (LRWC) and pigment systems. Hydrogen peroxide (H2O2) and lipid peroxidation (malondialdehyde [MDA]) levels increased by 2.78 and 2.24-fold, respectively, in plants under Cd stress, resulting in enhanced electrolyte leakage. Following foliar application to Cd-treated plants, JA restored growth, biomass yield, LRWC and pigment systems to appreciable levels and reduced levels of H2O2, MDA and electrolyte leakage. Proline and glycine betaine concentrations increased by 5.73 and 2.61-fold, respectively, in faba bean under Cd stress, with even higher concentrations observed following JA application to Cd-stressed plants. Superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase levels rose by 87.47%, 130.54%, 132.55% and 37.79%, respectively, with Cd toxicity, with further enhancement of antioxidant activities observed following foliar application of JA. Accumulation of Cd in roots, shoots and leaves was also minimized by external supplementation of JA. In conclusion, JA mitigates the negative impacts of Cd stress in faba bean plants by inhibiting the accumulation of Cd, H2O2 and MDA, and by enhancing osmolyte and antioxidant activities that reduce oxidative stress.  相似文献   

18.
Field-applied salicylic acid (SA) could provide a potential protection against drought stress in onion large-scale production. Two-season field experiments were consecutively conducted in 2013/2014 and 2014/2015 to study the effect of 1 and 2 mM SA on growth, yield, plant water relations, chlorophyll a fluorescence, osmoprotectants, and water-use efficiency (WUE) in onion plants under four levels of irrigation (I120 = 120%, I100 = 100%, I80 = 80%, and I60 = 60% of crop evapotranspiration). Foliar application of SA enhanced drought stress tolerance in onion plants by improving photosynthetic efficiency and plant water status as evaluated by membrane stability index and relative water content. These results were positively reflected by improving plant growth, productivity, and WUE under drought stress conditions. Therefore, SA application may, in future, find application as a potential growth regulator for improving plant growth and yield under deficit irrigation by 20–40%.  相似文献   

19.
Field water stress is a common problem in crop production, especially in arid and semi-arid zones and it is widely hypothesized that silicon (Si) could reduce water stress in plants. We set up a greenhouse study to evaluate some silicon sources—potassium silicate (K2SiO3), calcium silicate (CaSiO3) and silica gel for growth and nutrient uptake by four grass species under adequate and deficit irrigation. The four species studied were Rhodes grass (Chloris gayana), Timothy grass (Phleum pratense), Sudan grass (Sorghum sudanense) and Tall fescue (Festuca arundinacea). For all species, the biomass yield response to applied silicon under deficit irrigation was significantly better than under adequate irrigation. The yield response of Rhodes grass across silicon sources was 205% under deficit irrigation compared with only 59% under adequate irrigation; for Sudan grass it was 49% compared with 26% and for Timothy, it was 48% compared with a mere 1%. The higher responses under deficit irrigation suggest that the plants relied more on silicon to endure drought stress. Biomass yield of individual plants also differed according to soil water levels with Timothy grass being the most sensitive to water stress as it exhibited the highest yield response (209%) to adequate irrigation. This was followed by tall fescue (122%) and Rhodes grass (97%). Sudan grass was the least affected by deficit irrigation, possibly on account of improved root mass and its natural drought tolerance. Strong associations were noted between the uptake of silicon and those of nitrogen (N) and phosphorus (P) irrespective of soil water condition, but the uptake of potassium (K) was more strongly correlated with that of Si under deficit than adequate irrigation. Improvements in plant growth following Si application could therefore be linked to enhanced uptake of major essential nutrients.  相似文献   

20.
Abstract

Improvement of agricultural water use efficiency is of major concern with drought problems being one of the most important factors limiting grain production worldwide. Effective management of water for crop production in water-scarce areas requires efficient approaches. Increasing crop water use efficiency and drought tolerance by genetic improvement and physiological regulation may be a means to achieve efficient and effective use of water. A limited water supply inhibits the photosynthesis of plants, causes changes of chlorophyll contents and components and damage to photosynthetic apparatus. It also inhibits photochemical activities and decreases the activities of enzymes in plants. Water stress is one of the important factors inhibiting the growth and photosynthetic abilities of plants through disturbing the balance between the production of reactive oxygen species and the antioxidant defence, causing accumulation of reactive oxygen species which induce oxidative stress to proteins, membrane lipids and other cellular components. A number of approaches are being used to enhance water use efficiency and to minimize the detrimental effect of water stress in crop plants. Proper plant nutrition is a good strategy to enhance water use efficiency and productivity in crop plants. Plant nutrients play a very important role in enhancing water use efficiency under limited water supply. In this paper we discuss the possible effective techniques to improve water use efficiency and some macronutrients (nitrogen, phosphorus, potassium, calcium and magnesium), micronutrients (zinc, boron, iron, manganese, molybdenum and chloride), and silicon (a beneficial nutrient) in detail to show how these nutrients play their role in enhancing water use efficiency in crop plant.  相似文献   

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