温湿度交互作用对闽楠幼苗形态和生理生化的影响

Interaction Effects of Temperature and Humidity on Morphological and Physio-biochemistry of Phoebe bournei Seedlings

以闽楠1年生盆栽幼苗为材料，采用人工模拟不同高温和相对湿度组合的方法，测定高温和湿度交互作用下不同处理时间闽楠幼苗叶片形态和生理生化指标变化。结果表明，随着温度的升高，相对湿度的降低，胁迫时间的延长，闽楠幼苗受到的胁迫逐渐由单一的高温胁迫演变成高温＋大气干旱胁迫以及高温＋大气干旱十土壤干旱三重胁迫，闽楠幼苗生理生化特性、外部形态受到的影响加剧。其在生理生化、形态上的反应和适应与单独的高温逆境胁迫一致，但程度不同。闽楠幼苗适宜生长的温度是25～30℃，在30℃高温条件下胁迫时间超过10d，不论大气相对湿度如何都应加强水分管理，应通过遮阴和浇水降低大气温度、提高大气相对湿度和土壤含水量。40℃＋50％组合则是闽楠幼苗不能承受的极限条件。

Different combinations of high temperature and humidity treatments were simulated to study the effects of the interaction of temperature and humidity on one-year-old potted seedlings of Phoebe bournei. Morphological, physiological and biochemical variations of the seedlings were investigated under different treatments. Along with the increase of temperature, decrease of the humidity, and the prolongation of time, P. bournei seedlings underwent from the initial monostress （high temperature） to multiple stresses （high temperature q-- atmospheric drought q- soil drought）, resulting in an intensified impacts of the stresses on morphological, physiological, and biochemical characteristics. The responses of the seedlings to the multiple stresses were similar with that to high temperature stress with different degrees. The opti- mal growing temperature for P. bournei was between 25 to 30~C. Additionally, enhanced water manage- ment by utilizing shading and watering to decrease atmospheric temperature, raise atmospheric relative hu- midity and soil water content, were necessary when the seedlings had been exposed to 30~C for more than 10 days. The extreme survival condition for P. bournei seedlings was a combination of 40~C of temperature and 50 % of relative humidity.