水位变化对高原湿地湖滨带优势植物水葱的生长胁迫

Growth stress of Scirpus tabernaemontani of dominant plant in plateau wetland lakeshore to water level fluctuating

关键词:  零地面水位  水葱  生长特性  丙二醛  脯氨酸

Key words:  zero ground water level   Scirpus tabernaemontani  growth characteristics  MDA  proline

摘要:

干旱等引起的水位变化使大面积湖泊湿地湖滨带退化消失,其对湿地植物及其群落的影响是近年来的研究热点,对生长于零地面水位环境水葱(实验组)的生长特性(相对生长速率、基茎、分枝数)和抗性相关物质(茎丙二醛、脯氨酸含量)进行研究,与正常水环境(淹水约20 cm)下生长的水葱(对照组)进行对比,以揭示地面水位变为零(干旱)对水葱生长产生的影响。结果表明:不同实验时间段,水葱的相对生长速率不同,5月,实验组和对照组分别为2.00 cm·d^-1和3.18 cm·d^-1; 6月中上旬,分别为2.35 cm·d^-1和2.44 cm·d^-1; 6月中下旬,分别为0.95 cm·d^-1和0.99 cm·d^-1; 7月之后,分别为0.02 cm·d^-1和0.05 cm·d^-1。实验组水葱平均分枝数为2.94枝/丛,对照组为4.86枝/丛; 实验组水葱基径为5.15 mm,对照组为7.33 mm; 实验组水葱茎的相对含水量为73.28%,对照组为75.28%; 实验组水葱平均丙二醛、脯氨酸含量分别为10.27 μg·kg^-1和9.44μmol·kg^-1,对照组分别为6.46 μg·kg^-1和6.40 μmol·kg^-1。实验组和对照组水葱除了茎相对含水量差异不显著,其余指标均差异显著(对照组优于实验组),这表明地面水位变为零相对不利于生葱生长,会降低主要植物为水葱的湿地生态系统的生产力,最终加速该种湿地生态系统退化演替。研究结果可为揭示气候变化(干旱)对湿地挺水植物的生长以及对高原湿地生态系统的影响提供科学依据。

Abstract:

Drought result in water level fluctuating led to large area lakeshore of wetland degenerate and disappear, the effects on wetland plants and communities had become one of the research hotspot in recent years, but the study on the growth(heights, relative growth rate, diameter, branches, relative moisture content)and resistance(the contents of MDA and proline)of Scirpus tabernaemontani that came from ground water level was zero(experimental group), compared with the S. tabernaemontani grew in normal water environment(control group, flooding about 20 cm), so as to reveal the impacts of S. tabernaemontani growth to zero ground water level(drought). The relative growth rate of S. tabernaemontani varied in different periods, the experimental group and control group were 2.00 cm·d^-1 and 3.18 cm·d^-1 in May, 2.35 cm·d^-1 and 2.44 cm·d^-1 in early June, 0.95 cm·d^-1 and 0.99 cm·d^-1 in late June, 0.02 cm·d^-1 and 0.05 cm·d^-1 after July respectively. The average number of branches of experimental group was 2.94 branches per plexus and control group was 4.86 branches per plexus. The diameter of experimental group was 5.15 mm and the control group was 7.33 mm. The relative moisture content of S. Tabernaemontani was 73.28% in experimental group and 75.28% in control group. The average content of MDA in the experimental group was 10.27 μg·kg^-1 and the control group was 6.46 μg·kg^-1. The average value of proline content was 9.44 μmol·kg^-1 in experimental group and the control group was 6.40 μmol·kg^-1. These indexes differences were all significant except for relative moisture content between experimental group and control group(The control group was better than that of the experimental group),which showed that zero ground water level was not conducive to S. tabernaemontani's growth, would decrease the productivity of wetland ecosystem that was mainly S. tabernaemontani, and would accelerate this wetland ecosystem degradation succession. This article would provide scientific basis for revealing the serious effects on the growth of wetland aquatic plants and plateau wetland ecosystem result from climate chang(drought).