缺镁诱导的纽荷尔脐橙叶脉肿裂初报

Preliminary Study on Vein Enlargement or Corkiness in Leaves of Newhall Navel Orange Suffering from Magnesium Deficiency

以1年生枳砧纽荷尔脐橙为材料进行盆栽沙培,观察缺镁植株叶脉肿裂与叶片黄化症状的进程,测定不同枝梢叶片相对叶绿素和镁硼元素含量,探讨缺镁对纽荷尔脐橙叶脉肿裂、叶片黄化的影响。结果显示,第3个月时缺镁组2龄秋梢叶出现叶脉肿裂、叶片黄化的症状,而且随着时间延长症状加重;第3个月时对照组和缺镁组1龄春夏梢叶的叶色无明显差异,在第4个月时缺镁组出现明显黄化症状。第3个月时缺镁组各枝梢叶的相对叶绿素含量均显著降低,并且下降幅度随着时间延长而明显增大。第4个月时缺镁组和对照组的硼含量均处于高量水平,而缺镁组各枝梢叶镁含量均处于严重缺乏水平。表明,缺镁不仅会导致纽荷尔脐橙叶片黄化,也会导致叶脉肿裂。

Newhall navel orange trees（Citrus sinensis Osbeck） grafted on trifoliate orange（Poncirus trifoliata L.）rootstock were grown in sand：perlite（1：1,V/V） medium and irrigated with nutrient solution containing 0 mM（Mg-deficiency） and 1mM（control） MgSO4,respectively.The progression of vein enlargement and/or corkiness and leaf chlorosis was monitored,and the content of Mg,B and relative chlorophyll of leaves on different shoots was measured.Results indicated that 2 year-old autumn leaves suffering from Mg-deficiency exhibited symptoms of vein enlargement or corkiness and leaf chlorosis in the 3rd month,and the symptoms worsened with the extension of the experiment.The color of 1 year-old spring and summer leaves treated without Mg was not significantly different from that treated with Mg within 3 months,however,leaf chlorosis appeared in Mg-deficiency treatments in the 4th month.Moreover,relative chlorophyll content in the leaves of different shoots with Mg deficient treatments decreased remarkably in the 3rd month and the chlorosis symptoms deteriorated significantly with the progress of the experiment.B content in leaves of the two treatments,i.e,with or without Mg,was high.The content of Mg element in the leaves with Mg deficient treatments was significantly low.Therefore,magnesium deficiency leaded to not only leaf chlorosis but also vein enlargement or corkiness of Newhall navel orange.