小叶锦鸡儿离体叶片对温度处理的某些生理响应

小叶锦鸡儿离体叶片分别经25、30、35、40、45、50、55℃等7个温度处理60min后, 测定了其光系统Ⅱ最大量子效率(F_v/F_m)和脯氨酸含量的响应。结果表明, 25~40℃的温度对F_v/F_m没有明显影响; 温度高于40℃, 首先使光合作用通过光系统Ⅱ的电子传递受到不同程度的阻抑; 当温度高于50℃, 使叶片光系统Ⅱ反应中心失活或破坏, 即小叶锦鸡儿叶片光系统Ⅱ反应中心可耐受的最高温度为50℃, 温度再高, 将对叶片造成高温伤害。另外, 在耐受范围内, 叶片中的脯氨酸含量可能表征了叶片遭受温度胁迫的程度。     

盐胁迫对孔石莼的生理生化影响

研究了盐肋迫对孔石莼（Ｕｌｖａ ｐｅｒｔｕｓａ）的生理生化效应。结果表明，随盐度增加，孔石莼细胞膜呈透性，组织中可深性粮及脯氨酸含量增加；盐肋迫对藻体膜脂肪酸的影响表现为，经不同盐度肋迫后，多聚不饱和脂肪酸百分比（∑ＰＵＦＡ／∑ＡＦ），平均链长（Ｍ．Ｌ．Ｃ），平均双链数（Ｍ．Ｄ．Ｂ．）均有不同和程度的减少。     

Salinity tolerance in Schinopsis quebracho colorado: Seed germination, growth, ion relations and metabolic responses

Soil salinity is a major abiotic stress influencing plant productivity worldwide. Schinopsis quebracho colorado is one of the most important woody species in the Gran Chaco, an arid and salt-prone subtropical biome of South America. To gain a better understanding of the physiological mechanisms that allow plant establishment under salt conditions, germination and seedling growth of S. quebracho colorado were examined under treatment with a range of NaCl solutions (germination: 0–300 mmol l⁻¹ NaCl; seedling growth: 0–200 mmol l⁻¹ NaCl). The aim was to test the hypothesis that S. quebracho colorado is a glycophite that shows different salt tolerance responses with development stage. Proline content, total soluble carbohydrates and Na⁺, K⁺ and Cl⁻ concentrations in leaves and roots of seedlings, and the chlorophyll concentration and relative water content of leaves were measured. Germination was not affected by 100 mmol l⁻¹ NaCl, but decreased at a concentration of 200 mmol l⁻¹. At 300 mmol l⁻¹ NaCl, germination did not occur. Seedling growth decreased drastically with increasing salinity. An increase in NaCl from 0 to 100 mmol l⁻¹ also significantly reduced the leaf relative water content by 22% and increased the proline concentration by 60% in roots. In contrast, total soluble carbohydrates were not significantly affected by salinity. Seedlings showed a sodium exclusion capacity, and there was an inverse correlation between Cl⁻ concentration and the total chlorophyll concentration. S. quebracho colorado was more tolerant to salinity during germination than in the seedling phase. The results suggest that this increased tolerance during germination might, in part, be the result of lower sensitivity to high tissue Na⁺ concentrations. The significant increment of proline in the roots suggests the positive role of this amino acid as a compatible solute in balancing the accumulation of Na⁺ and Cl⁻ as a result of salinity. These results help clarify the physiological mechanisms that allow establishment of S. quebracho colorado on salt-affected soils in arid and semi-arid Gran Chaco.     

Responses to salt stress in the halophyte Plantago crassifolia (Plantaginaceae)

General responses to salt stress have been investigated in the halophyte Plantago crassifolia. Seed germination was strongly inhibited by NaCl, although seed viability and germination capacity were not affected by salt pre-treatments. A concentration-dependent inhibition of plant growth was observed in the presence of NaCl, which was accompanied by the accumulation of Na⁺ ions in the leaves, as determined by cation exchange HPLC. A 20-fold increase of proline content in leaves was observed when plants were treated with 500 m NaCl, suggesting a protective role against high salinity stress for this amino acid, whose possible mechanism of action is discussed.     

低温对玉米幼苗生理反应的影响

将玉米晚熟品种吉单159三叶期幼苗进行6 ℃、10 ℃低温处理3天、6天,发现幼苗脯氨酸含量明显增加,电导率提高,可溶性蛋白含量随着低温处理时间的延长先增加后减少,叶绿素SPAD值减少,光合速率下降。     

骆驼蓬属叶中氨基酸组成与抗逆性的关系

实验结果证明：西北地区骆驼蓬属叶中总氨基酸和游离氨基酸组成中均以天冬氨酸、苏氨酸、丝氨酸、谷氨酸、丙氨酸、缬氨酸、苯丙氨酸、组氨酸、和脯氨酸为主要组分。其中，天冬氨酸、苏氨酸、谷氨酸、苯丙氨酸、和脯氨酸表现出种间的量值差异。不同生境下的骆驼蓬和多裂骆驼蓬均以天冬氨酸等９种氨基酸为主要组分，但因生境不同而在部分氨基酸含量上有明显差异。生于盐碱荒地的骆驼蓬，其脯氨酸含量为不同生境下同种的１１．３倍和８．８５倍。不同生境下的多裂骆驼蓬其脯氨酸含量依干旱胁迫减弱而降低。表明细胞中脯氨酸积累与植物的耐盐、抗旱性有关