莲雾遮光期叶片SPAD值和C、N、P、K含量的变化及其规律

Dynamic Change and Regular Pattern of SPAD Value and C, N, P, K Contents of Wax Apple Leaf under Shade Treatment

对大田莲雾成年树进行遮光处理,研究遮光叶片SPAD值及C、N、P、K含量的动态变化及其规律。结果表明:叶片SPAD值受叶龄和遮光互作影响,自然条件下,叶龄40 d左右SPAD值最大,达到63.0±2.49。短时间遮光对叶片SPAD值的影响不大,遮光40 d叶片SPAD值降到最低;长时间遮光会造成叶片早衰,限制树体营养生长。遮光对叶片N、P、K、C含量均有影响,在遮光过程中,叶片的C、N、P、K含量的变化情况不尽相同,但树体对遮光后形成的弱光条件均作出响应,然后通过自身的调节,慢慢使C、N、P、K趋同于自然条件下的含量水平。莲雾叶片的碳氮比(C/N)随着遮光时间的延长而呈增大趋势,遮光40 d左右比值达到顶峰,此时是莲雾栽培上进行催花的一个关键时间点。

This study investigated the dynamic change and regular pattern of SPAD value and C,N,P,K contents of wax apple [Syzygium sarnarangense （Bi.） Merr.et Perry] leaf on shade treatment.The results showed that SPA D value was affected by the interaction of foliar age and shade treatment.The SPA D value with the value number of 63.0±2.49 was the maximum in the leaf with foliar age of 40 d at non-treatment.Slightly affected leaf SPA D value in short-term treatment and the SPA D value minimum under 40 d.The leaf senility and restrained growth would be observed in long-term shade treatment.The contents of N,P,K and C in leaf were affected by shade treatment.But the contents of N,P,K and C in leaf with low-light condition would be adjusted to normal afterwards.The ratio of C/N would be increased as the low-hght treatment extended,and the maximum would be appeared at around 40 d,which was the key to flower forcing..