应用叶位差诊断香蕉钾素营养的研究

应用叶位差诊断香蕉钾素营养的研究表明:传统的以第三叶片作为钾素诊断材料埘施钾不敏感,找出了香蕉对施钾的敏感部位是低位叶的中前部的叶(主)脉。明确了采用自顶向下计第5叶和第1叶叶脉含钾的比值(Vm/Im),来评价香蕉的钾素营养状况;叶脉采样的代表部位为叶片与叶主脉的连接带和采用混合样分析的可行性。比较了影响鲜样浸提率的三个主要因子,选出其优化组合;论述了采用叶位差诊断符合香蕉营养的生物学特性,拟定Vm/Im值<1.0为供钾不足,>1.0为供钾充足。证明使用叶位差法比当前传统的第三叶片法有更宽松的采样期,满足及时指导施钾的需要,并可以消除不同香蕉品种含钾量不同造成的困难。Vm/Im值与香蕉鲜果产量有显著的相关关系。

STUDY ON THE UTILIZATON OF THE RATIO OF LEAVES K CONTENT FOR K NUTRIENT DIAGNOSIS OF BANANA

A Study on the utilization of the ratio of K content between 5th and 1st leaves (v m /Im) for K nutrient diagnosis was carried out in 1986~1991. It was found that the K content tested by routine method with 3rd blade greatly varied caused by many factors, but comparatively smaller by K supplement. The most sensitive part to K ftertilization was in the mid-upper midrib at low positions. The relative value of K content, expressed by Vm/Im, in the midrib between 5th and 1st leaves from top, was used for evaluating the K nutrient status of banana. The sampling part was in the connective zone between midrib and blade. The feasiblity of testing by mixture samples was defined and three factors affecting extraction rate were compared. Based on the above mentioned results, the index Vm/Im was set, the value <1.0 as K defficiency, >1.0 as sufficiency. This method offered a longer period for sampling than 3rd blade did and eliminated the trouble caused by the difference of K content among the varieties, and make the application more convenience. Vm/Im value had significant possitive correlation with fresh-fruit yield.