Glycinebetaine Improves Chilling Tolerance in Hybrid Maize

Plant growth and development is hampered by various environmental stresses including chilling. We investigated the possibility of improving chilling tolerance in hybrid maize by glycinebetaine (GB) seed treatments. Maize hybrid (Hycorn 8288) seeds were soaked in 50, 100 and 150 mg l^?1 (p.p.m.) aerated solution of GB for 24 h and were dried back. Treated and untreated seeds were sown at 27 °C (optimal temperature) and at 15 °C (chilling stress) under controlled conditions. Germination and seedling growth was significantly hindered under chilling stress. Moreover, chilling stress significantly reduced the starch metabolism and relative water contents (RWC), and increased the membrane electrolyte leakage. However, activities of antioxidants (catalase, superoxide dismutase and ascorbate peroxidase) were increased under stress conditions. Seed treatments with GB improved the germination rate, root and shoot length, seedling fresh and dry weights, leaf and root scores, RWC, soluble sugars, α‐amylase activity and antioxidants significantly compared with untreated seeds under optimal and stress conditions. Induction of chilling tolerance was attributed to maintenance of high tissue water contents, reduced membrane electrolyte leakage, and higher antioxidant activities and carbohydrate metabolism. Seed treatment with 100 mg l^?1 GB was the best treatment for improving the performance of hybrid maize under normal and stress conditions compared with control and other levels used.     

Exploring the Role of Calcium to Improve Chilling Tolerance in Hybrid Maize

Abiotic stresses, including chilling, impede the plant growth and development mainly by oxidative damage. In this study, seed priming with CaCl₂ was employed to reduce the damage caused by chilling stress in hybrid maize. Maize hybrid (Hycorn 8288) seeds were soaked in 50, 100 and 150 mg l⁻¹ (ppm) aerated solution of CaCl₂ for 24 h and dried. Treated and untreated seeds were sown at 27 °C (optimal temperature) and 15 °C (chilling stress) under controlled conditions. Seed priming with CaCl₂ significantly reduced the chilling damage and improved the germination rate, root and shoot length, and seedling fresh and dry weights. Activities of antioxidants, including catalase, superoxide dismutase and ascorbate peroxidase, were also improved. Soluble sugars and α-amylase concentrations determined as general metabolic indicators of stress were also increased by seed priming with CaCl₂. Priming also improved the performance of maize at optimal temperature. Maintenance of tissue water contents, reduction in membrane leakage and increase in antioxidant activities, and carbohydrate metabolism seemed to induce chilling tolerance by CaCl₂. Seed priming with 100 mg l⁻¹ CaCl₂ was the optimal concentration in improving the performance of hybrid maize both under optimal and stress conditions.     

Activation of Antioxidant System by KCl Improves the Chilling Tolerance in Hybrid Maize

As maize is a chilling-sensitive crop, low temperatures during the early stages of development can be injurious to crop growth and development. Prime mechanism behind chilling-induced damage is oxidative stress. This study was undertaken to improve the chilling tolerance in hybrid maize by seed priming with KCl. For priming, seeds of the maize hybrid Hycorn 8288 were soaked in 50, 100 and 150 mg l⁻¹ aerated solution of KCl for 24 h and then re-dried close to original weight. Primed and untreated seeds were sown at 27 °C (optimal temperature) and at 15 °C (chilling stress) under controlled conditions. Seed priming improved the performance of maize under both normal and stress conditions. It was found that the chilling tolerance in maize is well associated with the enhanced capacity of the anti-oxidative system. Priming with KCl significantly improved the chilling tolerance mainly by the activation of antioxidants including catalase, superoxide dismutase and ascorbate peroxidase enzymes. KCl treatments also improved the germination rate and time, root and shoot length, and fresh and dry weights of seedlings compared with control. Soluble sugars and α-amylase activity determined as general metabolic indicators of stress were also improved by seed priming with KCl. Other possible bases of chilling tolerance in maize included maintenance of high tissue water contents, reduced electrolyte leakage and carbohydrate metabolism. Seed treatment with 100 mg l⁻¹ KCl was the best treatment to improve the performance of hybrid maize both under normal and chilling stress conditions.     

Effects of the Seed Film Coating Salicylic Acid on the Chilling Tolerance of Cotton Seedlings

The objective of this study was to investigate the effect of the different concentrations of the seed film coating salicylic acid on the cold tolerance of cotton seedlings using the sand culture method. The physiological response of cell membrane permeability, protective enzyme activity and osmotic adjustment of cotton seedling were measured before and after at low temperature stress and at normal temperature. The results showed that 1-10 mmol·L^－1 of seed film coating with salicylic acid seed coating treatment could effectively alleviate damage to cotton seedlings at low temperature, and the accumulation of the relative electrical conductivity and malondialdehyde were reduced on cotton seedlings. The activity of superoxide dismutase, peroxidase, catalase, and soluble protein, soluble sugar and proline contents increased sharply. These results indicate that film coating with salicylic acid can alleviate the effects of low temperature stress on seedling growth inhibition and improve the cotton seedlings by providing chilling tolerance, and the optimum treatment concentration salicylic acid is 5 mmol·L^－1.     

不同温度水杨酸引发对干旱胁迫下玉米种子发芽及幼苗生理特性的影响

为探究不同温度水杨酸(SA)引发对水分胁迫下玉米种子发芽和幼苗生长、生理特性的影响,以‘郑单958’、‘金甜808’和‘京科糯2000’为试验材料,设置5组处理(CK、5、10、15、20℃)研究干旱胁迫下幼苗生长表现。结果表明,水杨酸引发显著提高了玉米幼苗抗氧化酶活性,增加了渗透调节物质含量,降低了丙二醛(MDA)含量,缓解了水分胁迫对玉米生长的影响。其中,玉米发芽参数（发芽率、发芽势、发芽指数和活力指数）,‘郑单958’和‘金甜808’以15℃引发处理最高,较对照分别提高了16.67%、21.26%、17.69%、25.39%和10.88%、8.76%、10.02%、26.83%;而‘京科糯2000’以10℃引发处理最高,较对照提高了16.48%、10.73%、14.27%和32.00%。可见,种子引发增强了干旱胁迫下玉米种子的发芽能力,本研究结果可为种子引发在旱地玉米生产上的应用提供理论依据。     

水杨酸对渗透胁迫下玉米种子萌发和幼苗生长的影响

分别采用不同浓度的甘露醇和水杨酸处理玉米种子。结果表明:水杨酸处理对玉米种子的发芽率以及苗高、根长、根数、苗鲜重、根鲜重及根冠比都得到提高,说明水杨酸对玉米种子发芽和幼苗生长的有促进作用,可以在一定程度上解除渗透胁迫。     

引发处理对柳枝稷种子萌发及幼苗生长特性的影响

通过对柳枝稷种子进行不同引发后回干处理,在温度为25℃的条件下,用发芽纸作为基质来研究不同引发处理对柳枝稷种子的萌发和幼苗生长特性的影响.本研究主要测定发芽势、发芽率、每日发芽速度、根长、苗长、叶面积、根干重、根鲜重、幼苗叶绿素含量及电导率等生理指标.结果表明:在几种引发处理方法中,H2O引发处理效果最好,和对照相比,提高了柳枝稷种子的发芽及幼苗生长量,降低了膜透性,而CuSO4处理效果最差,不宜用作柳枝稷种子引发处理.     

Seed Priming Enhances the Performance of Late Sown Wheat (Triticum aestivum L.) by Improving Chilling Tolerance

In rice–wheat systems, late sowing of wheat is the major reason of low yield. This yield reduction is principally due to lower and erratic germination, and poor crop establishment because of low temperature prevailing. The present study was conducted to explore the possibility of improving late sown wheat performance by seed priming techniques. Seed priming strategies were: on‐farm seed priming, hydropriming for 24 h, seed hardening for 12 h and osmohardening with KCl or CaCl₂ for 12 h. Seed priming improved emergence, stand establishment, tiller numbers, allometry, grain and straw yield, and harvest index. However, seed priming techniques did not affect plant height, number of spikelets, number of grains and 1000 grain weight. Osmohardening with CaCl₂ gave more grain and straw yield and harvest index compared with control and other priming treatments, followed by osmohardening with KCl and on‐farm seed priming. Improved yield was attributed principally to better stand establishment and improved number of fertile tillers. Seed priming techniques can be effectively used to improve the performance of late sown wheat.     

Chilling Tolerance of Maize Seedlings in the Field during Cold Periods in Spring is Related to Chilling-Induced Increase in Abscisic Acid Level

Recent studies on chilling tolerance mechanisms in maize revealed a significant positive correlation between genotypic chilling tolerance and chilling‐induced accumulation of the stress hormone abscisic acid (ABA) under controlled growth chamber conditions. Based on this and other results, the hypothesis was developed that chilling tolerance in maize is related to the ability to accumulate large amounts of ABA rapidly, as a protection against chilling injury. The objective of the present study was to test this hypothesis under field conditions during natural cold weather periods in spring, which often cause severe chilling injury in maize fields. In two experiments at two locations in Europe with contrasting climates, eight maize genotypes with different genotypic chilling tolerance were cultivated in spring in the field according to agronomic practice for maize. Before and at the end of cold weather periods, ABA levels and water contents were determined in the third leaves. It was found that chilling‐tolerant genotypes accumulated higher amounts of ABA during the chilling period than chilling‐sensitive genotypes. A significant positive correlation between chilling tolerance and the levels of ABA in the leaves was found. These results support the above‐mentioned hypothesis. In contrast to earlier studies performed under growth chamber conditions, the water content in chilled leaves was mostly higher than in non‐chilled leaves. The increase in ABA is therefore not attributable to chilling‐induced water deficit, but probably to the low temperature itself.     

Improving the Drought Tolerance in Rice (Oryza sativa L.) by Exogenous Application of Salicylic Acid

Drought stress encumbers the rice growth predominantly by oxidative damage to biological membranes and disturbed tissue water status. In this study, the role of salicylic acid (SA) to induce drought tolerance in aromatic fine grain rice cultivar Basmati 2000 was evaluated. SA was applied as seed and foliar treatments. For seed treatment, rice seeds were soaked in 50, 100 and 150 mg l⁻¹ aerated solution of SA for 48 h and then dried back. Treated and untreated seeds were sown in plastic pots in a phytotron. At four leaf stage, one set of plants was subjected to drought stress, while the other remained well watered. Drought was maintained at 50 % of field capacity by watering every alternate day. For exogenous application, SA was applied 50, 100 and 150 mg l⁻¹ at five leaf stage. In the control, SA was neither applied exogenously nor as seed treatment. Drought stress severely affected the seedling fresh and dry weight, photosynthesis, stomatal conductance, plant water relations and starch metabolism; however, SA application improved the performance of rice under both normal and stress conditions. Drought tolerance in rice was well associated with the accumulation of compatible solutes, maintenance of tissue water potential and enhanced potency of antioxidant system, which improved the integrity of cellular membranes and facilitated the rice plant to sustain photosynthesis and general metabolism. Foliar treatments were more effective than the seed treatments. Foliar application with 100 mg l⁻¹ (FA 100) was the best treatment to induce the drought tolerance and improve the performance under normal and stress conditions compared with the control or other treatments used in this study.     

水杨酸对玉米种子萌发早期耐旱性的影响

为了探讨水杨酸(SA)引发对干旱胁迫下玉米种子生理生化特性的影响,以郑单958玉米品种为试验材料,在15℃黑暗下用0.1 mmol/L的SA引发处理36h,在15％的PEG-6000模拟干旱条件下吸胀不同时间(0,12,24,36,48 h),研究SA引发对干旱胁迫下玉米种胚、胚乳和种皮生理生化特性的影响.结果表明,干旱胁迫期间,种胚中CAT活性、胚乳中可溶性糖含量、种皮中可溶性蛋白含量增加.相对未引发种子,SA引发显著提高了种子CAT活性、可溶性糖含量、可溶性蛋白含量.因此,0.1 mmol/L SA引发处理可以提高玉米种子萌发早期的抗旱性.     

玉米耐低温冷害研究进展

玉米是典型的喜温C4作物,低温冷害胁迫是影响玉米生产的重要非生物逆境因素。为了研究低温对玉米生长发育的影响,归纳了玉米在低温胁迫条件下生理生化指标、光合作用参数的变化及耐冷遗传机制等方面的研究进展,并介绍了国内外抵御低温冷害所采取的方法,探讨了玉米耐低温研究的方向,提出玉米耐低温研究应更加注重玉米耐冷种质资源的创新及耐冷基因的挖掘利用。     

氯虫苯甲酰胺拌种对玉米种子活力及幼苗生长的影响

为研究氯虫苯甲酰胺拌种对玉米种子萌发、幼苗生长及生理生化指标的影响,采用平皿法和盆栽法研究氯虫苯甲酰胺不同剂量(0.5、1、2、3、4 g/kg)拌种处理对玉米种子萌发、幼苗生长量（株高、根长、根冠比等）以及生理生化指标（保护酶、根系活力、叶绿素含量等）的影响。结果表明：氯虫苯甲酰胺在0.5~3 g/kg剂量下拌种处理能明显提高玉米种子发芽势、发芽率、发芽指数和活力指数;增加幼苗期生长量;诱导幼苗叶片中CAT、POD、SOD、PAL、PPO活性升高;提高根系活力、叶绿素含量、还原糖含量及可溶性蛋白含量。氯虫苯甲酰胺在4 mg/kg剂量时对玉米植株的生长有一定的抑制作用,但各项指标仍高于空白对照。结果表明：合适剂量的氯虫苯甲酰胺拌种可以显著促进玉米种子萌发和幼苗生长。     

Abscisic Acid May Alter the Salicylic Acid‐Related Abiotic Stress Response in Maize

The effect of 0, 0.05 or 0.1 mm abscisic acid treatment on chilling tolerance and salicylic acid‐related responses was investigated in young maize seedlings (Zea mays L., hybrid Norma). Although the pre‐treatment of maize seedlings with abscisic acid slightly decreased the chlorophyll content, it also reduced the level of chilling injury caused by 6 days of cold treatment at 5 °C. Under normal growth conditions, increased levels of bound salicylic acid and of bound ortho‐hydroxycinnamic acid were observed in the leaves during abscisic acid treatment. In the roots, abscisic acid did not affect the free and bound salicylic acid levels, but increased the amount of free and bound ortho‐hydroxycinnamic acid. The activity of glutathione‐S‐transferase increased on the 3rd day of abscisic acid treatment, whereas it did not change when followed by cold stress, compared with the control leaves. In the roots, the activities of glutathione reductase, glutathione‐S‐transferase and ascorbate peroxidase increased during the abscisic acid treatment, and those of glutathione‐S‐transferase and ascorbate peroxidase were also stimulated when abscisic acid pre‐treatment was followed by cold stress, compared with the control roots. Our results suggest that an overlap may exist between the abscisic acid‐induced cold acclimation and the salicylic acid‐related stress response.     

水杨酸诱导黄瓜幼苗抗冷性的基因表达

摘要 ：【研究目的】水杨酸 (Salicylic acid,SA) 能诱导植物提高抗生物胁迫和非生物胁迫(冷胁迫等)的能力。为研究SA对非生物胁迫下植物基因表达的影响,【方法】以黄瓜 (“新优30”) 幼苗为试材,用SA (3mmol/L,pH6.0) 溶液和蒸馏水处理后,经7℃冷胁迫48h,提取叶片总RNA并反转录cDNA,【结果】利用mRNA差异显示技术分离出12个差异表达cDNA片段,经反向斑点杂交验证其中2个（SICCL_1 和SICCL_2）为高差异表达片段。序列测定和Blast分析表明,SICCL_1与甜瓜中黄瓜花叶病毒 (Cucumber Mosaic Virus, CMV) 相关基因AM734282有88%同源性;SICCL_2与毛柽柳中NaHCO3胁迫相关基因THL24h-106有86% 同源性。【结论】由此推测,SA诱导植物抵抗生物胁迫和非生物胁迫的能力可能是通过诱导植物某些相同基因的表达来实现的。     

不同浓度柠檬酸对甜菜种子的引发影响

为了研究柠檬酸作为引发剂对甜菜单粒种引发的影响效果,并为甜菜种子包衣剂物料的选择提供依据。试验以甜菜单粒种1113×NY051为材料,不同浓度柠檬酸为引发剂,用直接测量法得到发芽势、发芽率等数据。结果表明,处理甜菜单粒种时,不同浓度柠檬酸和不同时间梯度的9个处理都能够有效地促进材料1113×NY051的发芽势、发芽率、发芽指数和活力指数,降低电导率。其中,5 mmol/L柠檬酸对甜菜种子1113×NY051在8、12、24 h 3个不同时间情况下的发芽势、发芽率、发芽指数和活力指数指标均高出对照组(CK),电导率低于对照组(CK)。不同浓度的柠檬酸能显著促进种子萌发,随着处理时间的变化和试剂浓度的不同对引发效果均有不同影响。     

种子沙引发对转基因抗虫棉耐盐性的影响

 以转基因抗虫棉花品种中棉所41和浙905为材料,以其遗传背景品种中棉所23为对照,研究了种子沙引发处理对转基因抗虫棉品种在0%、1.0%和1.5% NaCl浓度下的萌发率、出土率和幼苗生长特性的影响。结果表明,沙引发处理对转基因抗虫棉品种在盐胁迫下的种子萌发和幼苗生长具有明显的效果,但对于非转基因棉品种的效果不明显。幼苗子叶、茎秆和根的超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性和丙二醛（MDA）含量测定结果表明,沙引发处理使棉花幼苗的子叶和根部维持了较高的SOD与POD活性,但显著减少幼苗体内MDA的积累,说明沙引发有助于促进棉花在逆境下幼苗生长发育和抗逆性的提高。     

Seed Priming with Ascorbic Acid Improves Drought Resistance of Wheat

The study, consisting of two independent experiments, was conducted to evaluate the role of seed priming with ascorbic acid (AsA) in drought resistance of wheat. In the first experiment, seeds of wheat cultivars Mairaj‐2008 and Lasani‐2008 were either soaked in aerated water (hydropriming) for 10 h or not soaked (control). In the second experiment, seeds of same wheat cultivars were soaked in aerated (2 mm ) AsA solution (osmopriming) or water (hydropriming) for 10 h. In both experiments, seeds were sown in plastic pots (10 kg) maintained at 70 % and 35 % of water‐holding capacity designated as well watered and drought stressed, respectively. Both experiments were laid out in a completely randomized design with six replications. Drought caused delayed and erratic emergence and disturbed the plant water relations, chlorophyll contents and membranes because of oxidative damage; however, root length in cultivar Lasani‐2008 was increased under drought. Hydropriming significantly improved the seedling emergence and early growth under drought and well‐watered conditions; however, improvement was substantially higher from osmopriming with AsA. Similarly, osmopriming with AsA significantly improved the leaf emergence and elongation, leaf area, specific leaf area, chlorophyll contents, root length and seedling dry weight. Owing to increase in proline accumulation, phenolics and AsA, by seed priming with AsA, plant water status was improved with simultaneous decrease in oxidative damages. These improved the leaf emergence and elongation, and shoot and root growth under drought. However, there was no difference between the cultivars in this regard. In conclusion, osmopriming with AsA improved the drought resistance of wheat owing to proline accumulation and antioxidant action of AsA and phenolics, leading to tissue water maintenance, membrane stability, and better and uniform seedling stand and growth.     

种子引发对碱胁迫下甜高粱种子萌发及幼苗生长的影响

为研究碱胁迫下种子引发对萌发及幼苗生长的影响,以甜高粱杂交种‘通甜1号’为试验材料,利用500μmol/Lγ-氨基丁酸(GABA)对种子进行引发处理。采用盆栽土培试验,将NaHCO3:Na2CO3=5:1的混合碱胁迫液设3个水平(0、50、100 mmol/L)模拟碱胁迫,研究GABA种子引发处理对碱胁迫下高粱种子萌发状况及幼苗生长的影响。结果表明:随着碱胁迫强度增加,无论是经过引发处理的种子还是未经过引发处理的种子,其吸水量、萌发指数、出苗率和成苗率显著下降,幼苗生长受到限制,生物量积累降低。同等碱胁迫浓度下,经过引发处理的种子与未经过引发处理的种子相比,种子吸水量、萌发指数、胚的生长及幼苗叶面积均显著提高。低浓度碱胁迫条件下,经过引发处理的种子与未经过引发处理的种子相比,幼苗的出苗率和存活率较高、生长至第7天的株高和茎粗及总生物量均显著增加。试验表明,经过引发处理的种子可以不同程度地提高碱胁迫下甜高粱种子萌发指数,缓解碱胁迫对幼苗的不利条件,促进幼苗生长,提高耐碱性。     

高效液相色谱法测定羧甲基壳聚糖/水杨酸处理的葡萄柚果实中水杨酸含量

以葡萄柚果实为试材,分别采用三氯乙酸/乙醚、三氯乙酸/三氯甲烷、乙酸乙酯/环己烷提取果皮水杨酸,采用高效液相色谱法测定其含量,筛选得出简单易行的提取及测定葡萄柚果皮水杨酸含量的方法.利用此方法对15 g/L羧甲基壳聚糖(CMC)、200mg/L水杨酸(SA)单独及复合处理的葡萄柚果皮内源水杨酸含量进行测定分析.结果表明,可采用三氯乙酸/乙醚从葡萄柚果皮提取的水杨酸分离效果较好,测定最佳色谱条件为:Eclipse XDB-C18柱(150 mm×4.6 mm,5 μm),流动相0.2 mol/L pH 5.5乙酸钠缓冲溶液-甲醇(40∶60),检测波长296 nm,流速0.8 mL/min,进样量5 μL.水杨酸质量浓度在3.91～500 μg/mL范围内与峰面积呈现良好的线性关系,处理样品果皮的游离态水杨酸含量范围为18～47.6 μg/g,结合态水杨酸含量范围是68.05～73.85 μg/g.在室温贮藏的28 d内,相比未处理果实(对照),经诱导处理的游离态水杨酸和结合态水杨酸含量均呈升高的趋势,羧甲基壳聚糖/水杨酸复合处理的游离态水杨酸含量显著高于单独处理含量(P＜0.05).采用三氯乙酸/乙醚提取葡萄柚果皮水杨酸具有较高的分离度,本试验所得HPLC方法简单易行,可以用于葡萄柚果皮内源水杨酸的提取分离和测定.