外源脱落酸对湿地植物美人蕉抗寒性的影响

低温时植物枯萎导致人工湿地运行效率降低, 研究将脱落酸应用于湿地植物, 以期提高其抗寒性。采用0、5、10、15、20和25 mg/L的脱落酸(ABA)对美人蕉(Canna indica L.)幼苗叶面进行喷施并进行阶段性降温培养, 评价各组在0℃时的抗寒性, 筛选出最适ABA处理浓度。结果表明: 在低温条件下, 经过适宜浓度外源脱落酸预处理组的丙二醛(MDA)、相对电导率显著性低于对照组; 脯氨酸、可溶性糖和蛋白质含量显著高于对照组, 超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性也有所提高。综合以上指标, 认为15 mg/L脱落酸处理为最佳。随后将其应用于人工湿地, 对其冬季净化效果进行评估。结果发现, 15 mg/L脱落酸预处理可使人工湿地的冬季TP、TN和COD去除率显著高于对照组(P<0.05)。由此可见, 一定浓度的脱落酸预处理能够有效提高美人蕉的抗寒性, 并提高人工湿地冬季净化效果。

STUDY ON INCREASE OF THE COLD RESISTANCE AND OVERWINTERING EFFECT OF CANNA INDICA LINN IN CONSTRUCTED WETLAND BY ABSCISIC ACID

Plants are an important part of constructed wetlands, but most wetland plants cannot survive in low temperature environments, and their microbial activity is inhibited, thus limiting the application of constructed wetlands at low temperature. This study explored the role of abscisic acid at 0, 5, 10, 15, 20 and 25 mg/L to improve wetland plants in cold resistance. The results showed that under low temperature conditions, exogenous abscisic acid significantly reduced malondialdehyde (MDA) and relative conductivity, increased the contents of proline, soluble sugar and protein in seedlings, and enhanced SOD, POD and CAT activities with the best effects at 15 mg/L abscisic acid group. Then 15 mg/L abscisic acid was applied to constructed wetlands to evaluate its winter purification effect. 15 mg/L abscisic acid significantly increased the removal rate of TP, TN and COD in constructed wetlands in winter (P<0.05). Thus, abscisic acid can effectively improve the cold resistance of Canna indica and improve the purification effect of constructed wetland in winter. This research provides new ideas and solutions for breaking through the bottleneck of low-temperature operation of wetland systems.