川西亚高山甘西鼠尾草对海拔梯度的生理生化响应

Physiological and Biochemical Responses of Salvia przewalskii to Altitude Gradient in Subalpine Area of Western Sichuan

【目的】探寻甘西鼠尾草(Salvia przewalskii)应对海拔变化的生理生态响应规律,为高效预测气候变化背景下植物响应及适应性变化提供参考依据。【方法】在川西亚高山地区,选取6个海拔(2400、2600、2800、3000、3200、3400 m),通过叶片气体交换和生化技术检测等方法,分别测定甘西鼠尾草的叶片光合特性、非结构性碳水化合物、丙二醛、脯氨酸及抗氧化酶等生理生化指标,并综合对比和分析各指标沿海拔的变化及相关性。【结果】随着海拔升高,甘西鼠尾草叶片光饱和净光合速率、气孔导度、胞间CO_(2)浓度、蒸腾速率、淀粉、可溶性糖、非结构性碳水化合物和脯氨酸总体呈先升高后降低的变化趋势,在海拔2800 m时出现最大值,其与最低海拔相比分别提高了30.3%、78.7%、7.6%、23.0%、42.9%、30.1%、37.4%和48.7%;丙二醛、超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶总体呈先下降后上升的变化趋势,在海拔2800 m时出现最低值,其和最低海拔相比分别下降了16.2%、12.5%、25.4%、6.4%和11.3%;光补偿点和光饱和点随海拔升高而增加。甘西鼠尾草叶片理化性状具有较强可塑性,可塑性指数为0.02~0.56,海拔与光饱和净光合速率(P<0.01)、气孔导度(P<0.05)、光补偿点(P<0.01)、可溶性糖(P<0.05)、非结构性碳水化合物(P<0.05)、丙二醛(P<0.01)、脯氨酸(P<0.05)、超氧化物歧化酶(P<0.01)、过氧化物酶(P<0.01)、过氧化氢酶(P<0.01)和抗坏血酸过氧化物酶(P<0.01)显著正相关,但海拔与蒸腾速率显著负相关(P<0.01)。【结论】为应对不同海拔生境,甘西鼠尾草通过调节叶片自身生理生化特性以适应海拔变化,高海拔或低海拔生境限制了甘西鼠尾草叶片碳同化,为确保其自身的正常生长发育,植物通过优化资源分配以平衡生长和生存,维持稳定净碳增益。

【Objective】Explore the physiological and ecological response patterns of Salvia przewalskii to changes of altitude,providing a reference basis for efficient prediction of plant responses and adaptive changes under climate change.【Methods】S.przewalskii was selected as the research material from six altitudes(2400,2600,2800,3000,3200,3400 m)in the subalpine area of Western Sichuan.Gas exchange and biochemical technologies were utilized to measure the physiological and biochemical parameters of leaves such as photosynthetic characteristics,non-structural carbohydrates,malondialdehyde,proline,and antioxidant enzymes.Comprehensive comparison and analyses were conducted to explore the changes and correlations of these indicators along altitudes.【Results】With rising altitude,the net photosynthetic rate under light saturation,stomatal conductance,intercellular CO_(2)concentration,transpiration rate,starch,soluble sugars,non-structural carbohydrates,and proline of S.przewalskii showed an overall trend of first increase and then decrease,and they showed maximum values at 2800 m.Compared to the lowest altitude,the values of those parameters at 2800 m were increased by 30.3%,78.7%,7.6%,23.0%,42.9%,30.1%,37.4%,and 48.7%,respectively Malondialdehyde,superoxide dismutase,peroxidase,catalase,and ascorbate peroxidase showed an overall trend of first decrease and then increase,and they showed minimum values at 2800 m.Compared to the lowest altitude,the values of those parameters at 2800 m were decreased by 16.2%,12.5%,25.4%,6.4%,and 11.3%,respectively.The light compensation point and light saturation point increased with rising altitude.The physiological and biochemical characteristics of leaves exhibited a strong plasticity with a range of 0.02~0.56.Altitude was significantly positively correlated with the net photosynthetic rate under light saturation(P<0.01),stomatal conductance(P<0.05),light compensation point(P<0.01),soluble sugars(P<0.05),non-structural carbohydrates(P<0.05),malondialdehyde(P<0.01),proline(P<0.05),superoxide dismutase(P<0.01),peroxidase(P<0.01),catalase(P<0.01),and ascorbate peroxidase(P<0.01),while significantly negatively correlated with the transpiration rate(P<0.01).【Conclusion】In response to different altitude,S.przewalskii adjusted physiological and biochemical characteristics of leaves.High or low altitudes limited carbon assimilation of leaves.To ensure normal growth and development,plants optimized resource allocation to balance growth and survival,and maintained net carbon gain.