水分胁迫对入侵植物薇甘菊幼苗生长的影响

The Effect of Water Stress on the Growth Yield of Invasion Plants of Mikania micrantha Seedlings

水分是影响薇甘菊(Mikaniamicrantha)生长的重要环境因子,但通过调控生长环境包括土壤水分和空气湿度来探讨这一入侵植物的适应能力的报道较少。本文通过设置2个水分梯度:处理Ⅰ土壤含水量30%￣60%和空气相对湿度80%￣90%,处理Ⅱ土壤含水量10%￣20%和空气相对湿度20%￣30%进行试验。结果发现土壤含水量在10%￣20%且空气相对湿度在20%￣30%时,水分胁迫能显著影响薇甘菊的幼苗生长和光合特性。胁迫条件下植株生长速率明显降低,最大净光合速率和最大量子效率分别是1.94μmol.m-2.s-1和64.91mmol.mol-1,比对照8.63μmol.m-2.s-1和211.34mmol.mol-1明显偏低。本文将空气相对湿度作为水分胁迫条件之一,阐述了空气相对湿度的增加能扩大薇甘菊的适生范围,并分析得出气孔限制可能是水分胁迫下薇甘菊生长受抑制的主要原因。

Moisture is the important environmental factor influencing the growth of Mikania rnicrantha. But few studies have described its adaptive capacity of adjusting and controlling the growth environment, including soil moisture and air humidity. The present study was conducted to set up 2 pieces of moisture gradient： control, 30%-60% of water content of soil and 80%-90% relative humidity of air; treatment Ⅰ, 10%-20% of water content of soil and 20%-30% relative humidity of air. The growth and photosynthetic characters of M. micrantha was influenced remarkably in treatment Ⅱ. In water stress conditions, the maximum net photosynthetic rate was only 1.94μtmol.m^-2.s^-1 and the maximum quantum efficiency 64.91 mmol.mol^-1 photons, obviously reduced as compared with control （8.63μtmol.m^-2.s^-1 and 211.34 mmol.m^-2.s^-1）. With relative humidity of air used as one of the factors of water stress, this study reveals that relative air humidity could expand the growth range of M. micrantha, and air venting is the main reasonthat limits the growth of M. micrantha in the water stress condition.