对3个品种(GT1、RRIM600、PR107)巴西橡胶(Hevea brasiliensis)实生苗进行不同N素(0%N,50%N,100%N)处理,分析比较叶片SPAD值、N素营养和农艺性状的变化及其关系。结果表明:(1)缺N胁迫明显降低了叶片SPAD值、叶片N含量和硝酸还原酶活性,缩小了叶蓬距、叶面积,且影响幅度随胁迫强度的加大而增大;(2)不同品种橡胶树实生苗对缺N胁迫的响应程度不同,总体上GT1较为敏感,PR107次之,RRIM600较不敏感;(3)橡胶树实生苗叶片SPAD值、叶蓬距、叶面积与叶片N含量、硝酸还原酶活性之间均呈显著或极显著正相关。因此,有可能采用测定叶片SPAD值、叶蓬距和叶面积等简易方法判断橡胶树新生叶蓬的N素营养状况。

Seedlings of three varieties (GT1,RRIM600,PR107) of Hevea brasiliensis were treated with low N (0%N,50%N,100%N) stress and the changes and their relationship of the leaf SPAD values,N nutrition and agronomic traits were studied.The results showed that:(1) low N stress significantly decreased the leaf SPAD value,leaf nitrogen content (LNC),nitrate reductase activity (NRA) and reduced distance between leaf-umbrella (DBL),leaf area (LA).And these impact aggrandized as the stress intensity increased.(2) Responses to low-N stress were in different degrees between different varieties of rubber tree seedlings.On the whole,GT1 was most sensitive to stress,PR107 next,and RRIM600 was the least sensitive.(3) The SPAD value,DBL,LA were significantly positive correlated with LNC,NRA in Hevea brasiliensis seedling leaves.Therefore,leaf SPAD value,DBL and LA would be shortcut measures to evaluate the nitrogen nutrient condition of rubber plant.