不同钙浓度对宽叶雀稗幼苗的生长和抗性生理的影响

研究不同钙浓度对宽叶雀稗(Paspalum wettsteinii)幼苗生长和生理的影响, 对于揭示宽叶雀稗对不同钙浓度环境的适应机理至关重要。该研究采用盆栽砂培试验, 研究不同钙浓度(0、5、25、50、100和200 mmol·L^-1 CaCl₂)和不同处理时间(7、14、21和28天)对宽叶雀稗幼苗生长、渗透调节物质含量、抗氧化酶活性、叶绿素含量和光合参数的影响。结果表明, 随着CaCl₂浓度的增加和处理时间的延长, 宽叶雀稗幼苗株高等形态指标、生物量、渗透调节物质含量、抗氧化酶活性、叶绿素含量和光合参数呈先增后减的趋势, 低钙浓度(5-50 mmol·L^-1)环境下, 株高、叶长、叶宽、根长和生物量与对照(0 mmol·L^-1)相比均升高, 脯氨酸、可溶性蛋白和可溶性糖含量、过氧化物酶、过氧化氢酶和超氧化物歧化酶活性提高, 丙二醛含量和胞间CO₂浓度降低、叶绿素含量增加以及净光合速率、蒸腾速率和气孔导度增强; 高钙浓度(200 mmol·L^-1)环境下, 脯氨酸、可溶性蛋白和可溶性糖含量、过氧化物酶、过氧化氢酶和超氧化物歧化酶活性降低, 丙二醛含量和胞间CO₂浓度增加, 叶绿素含量减少以及净光合速率、蒸腾速率和气孔导度减弱。结合隶属函数分析, 低钙盐浓度(5-50 mmol·L^-1)处理对宽叶雀稗幼苗无抑制作用, 说明宽叶雀稗对低钙浓度具有一定的耐受性; 而在高钙浓度(200 mmol·L^-1)下, 宽叶雀稗幼苗通过提高自身有机渗透调节物质含量、增强酶活性、增加叶绿素含量以及增强光合作用等方式来快速调节植物生理代谢功能, 进而适应高钙浓度环境条件。

Effects of different calcium concentrations on growth and physiology of Paspalum wettsteinii seedlings

Aims The study about the effects of different calcium concentrations on the growth and physiology of Paspalum wettsteinii seedlings is very important to reveal the adaptive mechanism of Paspalum wettsteinii to the environment with different calcium concentrations. Methods Potted sand culture was used to study the effects of different calcium concentrations (0, 5, 25, 50, 100 and 200 mmol·L^-1 CaCl₂) and different treatment times (7, 14, 21 and 28 d) on the growth, osmotic regulator content, antioxidant enzyme activity, chlorophyll content and photosynthetic parameters of Paspalum wettsteinii seedlings. Important findings Results showed that, with the increase of the CaCl₂ concentration and the extension of treatment time, the morphological indexes, biomass, osmotic regulators content, antioxidant enzyme activity, chlorophyll content and photosynthetic parameters of Paspalum wettsteinii seedlings displayed a similar trend of first increasing and then decreasing. Under the low calcium concentrations (5-50 mmol·L^-1), plant height, leaf length, leaf width, root length and biomass all increased. The contents of proline, soluble protein, soluble sugar and the activities of peroxidase, catalase, superoxide dismutase, chlorophyll content, net photosynthetic rate, transpiration rate and stomatal conductance increased as well, but, malondialdehyde content and intercellular CO₂ concentration decreased. Under the high calcium concentrations (200 mmol·L^-1), the contents of proline, soluble protein, soluble sugar and the activities of peroxidase, catalase and superoxide dismutase decreased. Malondialdehyde content and intercellular CO₂ concentration increased as well, but chlorophyll content, net photosynthetic rate, transpiration rate and stomatal conductance decreased. Combined with the membership function analysis, the treatment of low calcium concentrations (5-50 mmol·L^-1) had no inhibitory effect on the seedlings of Paspalum wettsteinii, indicating that Paspalum wettsteinii had certain tolerance to low calcium salt stress. Under the treatment of high calcium concentration (200 mmol·L^-1), Paspalum wettsteinii seedlings could rapidly regulate the physiological and metabolic functions of plants by increasing the content of organic osmotic regulating substances, enhancing enzyme activity, chlorophyll content and photosynthesis, so as to adapt to high calcium concentration environment.