脐橙叶片镁、硼含量变化与缺素黄化的关系

Seasonal Changes in Leaf Magnesium and Boron Contents and Their Relationships to Leaf Yellowing of Navel Orange (Citrus sinensis Osbeck)

以‘纽荷尔’和‘朋娜’脐橙品种为材料,研究了中亚热带季风区红壤果园的脐橙叶片镁和硼含量的动态变化,叶片镁和硼含量对叶绿素含量的影响及其与叶片缺素黄化的关系。两个品种的叶片含镁量均随叶龄增长而下降,6月果实进入膨大期后尤其明显,且与叶片黄化进程同步;叶片含硼量随叶龄增长而增加或稳定;两个品种的叶片含镁量与叶绿素含量呈极显著正相关(P<0.01),相关系数分别为0.9082和0.9063,而叶片含硼量与叶绿素含量相关不显著(P>0.05);缺镁是导致脐橙叶片缺素黄化的原因。

Seasonal changes in Mg and B contents in leaves of two navel orange varieties,Newhall and Skaggs Bonanza(Citrus sinensis Osbeck)on trifoliate orange [Poncirus trifoliata(L.)] rootstocks,growing on red soil in the middle subtropical monsoon climate zone,were monitored to study the effects of such changes on chlorophyll contents and leaf yellowing.Mg content decreased as leaves grew older and the most pronounced decrease occurred in June when the fruit began expanding.The decrease in Mg paralleled with the progress of leaf yellowing.In contrast,leaf B content increased or stabilized as leaf age increased.A significant positive correlation(P < 0.01)was found between Mg contents and chlorophyll contents as showed by high correlation coefficients of 0.9082 and 0.9063 in leaves of Newhall and Skaggs Bonanza trees,respectively.No significant correlation was shown between B contents and chlorophyll contents in the leaves of the two cultivars.Therefore,Mg deficiency was the reason for yellowing of leaves on navel orange trees.