灰化苔草对不同水位环境的生理适应性

水位是影响湿地植物生长发育和繁殖的重要因素,为明确不同水位环境对灰化苔草(Carex cinerascens)生理特性的影响,采用室内盆栽法,设置上升、下降与稳定3种水环境类型,各设置8 cm(0.2cm/d)、16cm(0.4 cm/d)、24 cm (0.6 cm/d)、32 cm (0.8 cm/d)、40 cm (1.0 cm/d)、48 cm (1.2 cm/d)、56 cm (1.4 cm/d)7个试验处理,以0 cm水位为对照,试验时间持续40 d。分析了不同水位条件下灰化苔草抗氧化酶活性、渗透调节物质含量、丙二醛含量和超氧阴离子产生速率等指标。研究结果表明:1)稳定水位中,8、16 cm淹水深度下,超氧阴离子产生速率、渗透调节物质含量和抗氧化酶活性与对照组之间差异显著。48、56 cm的淹水条件下,抗氧化酶活性与渗透调节物质先增后减、丙二醛与超氧阴离子产生速率持续增加;2)水位上升条件下,在0.2、0.4 cm/d变化强度下,20—30 d后丙二醛含量与超氧阴离子产生速率无显著变化。1.0 cm/d为灰化苔草生理调节耐受极限,当变化强度大于1.0 cm/d时、各生理指标与变化强度小于1.0 cm/d变化明显异常;3)水位下降条件下,受初始水位高度的影响。丙二醛含量在1.2、1.4 cm/d变化强度下呈现高-低-高的变化趋势,其余试验指标表现为先升后降的变化趋势,并且随着变化强度的增加、各生理指标变化的差异越来越大、由升高转向降低的时间节点不断延后。可见,淹水环境会破坏灰化苔草细胞内环境的稳态,相比稳定水位,灰化苔草的抗氧化与渗透调节系统能够更快的适应水位变化环境,并且短时间、低强度的水位变化一定程度能促进灰化苔草的生理代谢。

The physiological adaptability of Carex cinerascens to different water level environments

Water level is an important factor affecting the growth, development and reproduction of wetland plants. To clarify the effects of different water levels on the physiological characteristics of Carex cinerascens, the indoor pot method is used to set up three types of water environment: rising, falling and stable. Seven test treatments, including 8 cm (0.2 cm/d), 16 cm (0.4 cm/d), 24 cm (0.6 cm/d), 32 cm (0.8 cm/d), 40 cm (1.0 cm/d), 48 cm (1.2 cm/d), and 56 cm (1.4 cm/d) were set for each types of water environment, taking 0 cm water level as a control, the test time lasted 40 days. The indexes of antioxidant enzyme activity, osmotic adjustment substance content, malondialdehyde content and superoxide anion production rate of C. cinerascens under different water levels were analyzed. The results showed that 1) in the stable water level, the superoxide anion production rate, osmotic adjustment substance and antioxidant enzyme activity were significantly different from the control group at 8 cm and 16 cm flooding depth. Under 48 cm and 56 cm flooding conditions, antioxidant enzyme activity and osmotic adjustment substances increased first and then decreased, and malondialdehyde and superoxide anion production rates continued to increase. 2) Under the condition of risen water level, at a vibration intensity of 0.2 cm/d and 0.4 cm/d, the malondialdehyde content and superoxide anion production rate did not change significantly after 20-30 d. The 1.0 cm/d was the physiological regulation tolerance limit of C. cinerascens. When the processing intensity was greater than 1.0 cm/d, the physiological indexes and the processing intensity were less than 1.0 cm/d, and the change was obvious. 3) Under the condition of falling water level, it was affected by the initial water level. The malondialdehyde content showed a high-low-high trend at a processing intensity of 1.2 cm/d and 1.4 cm/d. The remaining test indicators showed a trend of increasing first and then decreasing, and with the increase of processing intensity, the difference in indicator changes continued to increase, and the time node from rising to the falling was continuous to delay. It could be seen that the flooded environment would destroy the homeostasis in the cells of C. cinerascens. Compared with the stable water level, the anti-oxidation and osmotic adjustment system of C. cinerascens could adapt to the water level changing environment faster, and the short-term, low-intensity water level change could promote physiological metabolism of C. cinerascens to a certain extent.