杨树凋落叶腐解对生菜生长和抗性生理的影响

本实验以生菜为受体,采用盆栽试验,对杨树凋落叶在土壤腐解过程的化感作用进行了研究.试验设置4个凋落叶添加水平,即：A1（30 g·pot-1）、A2（60 g·pot-1）、A3（90 g·pot-1）和对照CK（不施加凋落叶）,分别将各处理凋落叶与8 kg土壤混合后装盆,播种生菜.在播种后50 d测定生菜株高、生物量及抗性生理指标.结果表明：1）A3处理植株株高受到显著抑制,A2、A3处理植株生物量积累受到显著抑制;2）受体叶片超氧化物歧化酶（SOD）活性随着凋落叶量的增加呈先升后降的趋势;3）A2、A3叶片丙二醛（MDA）含量均大于对照（CK）,且随凋落叶处理量增大呈渐增趋势;4）各处理叶片可溶性糖（SS）含量均显著高于对照（CK）,可溶性蛋白（SP）含量则均显著低于对照（CK）.由此可见,杨树凋落叶在土壤腐解的过程中生菜的生长会受到影响,在高量处理时表现为明显的抑制.

Effects of Decomposed Leaf Litter of Populus on Growth and Resistance Physiology of Lactuca sativa

By using pot experiments, researches was conducted on the effects of leaf litter of Populous on the growth and resistance physiology of Lactuca sativa during the decomposition process of leaf litter. Each pot contained 8 kg soil mixed with 30,60,90 and 0 g leaf litter. Height, biomass, and several resistance physiology indexes of Lactuca sativa were determined on 50 d after sowing. The results showed that 1 ） the heigh of A3 was inhibited significantly on 50 d after planting,and the biomass of A2 and A3 was inhibited significantly; 2） The activities of superoxide dismutase （SOD） increased in low litter content and de- creased in higher litter content; 3 ）The content of malondialdehyde （MDA） of A2 and A3 was higher than that of control（CK） ,and moreover,it increased along with the addition of leaves; 4） The content of solu- ble sugar（SS） in each treatment was significantly higher than that of control（ CK）, whereas the content of soluble protein （SP） was significantly lower than that of control（CK）. On the whole ,the high content leaf litter of Populous had a serious allelopathic effect on Lactuca sativa during its initial decomposition process in soil.