不同砧木伏令夏橙对土壤pH值的适应性

THE ADAPTABILITY OF ‘VALENCIA'ORANGE ON DIFFERENT ROOTSTOCKS TO SOIL pH

本试验研究了紫色土pH值对枳砧、红桔砧和香橙砧伏令夏橙吸收Fe、叶绿素含量、过氧化物酶活性以及植株生长的影响。结果表明,香橙砧最耐碱;红桔砧其次;枳砧最不耐碱;而耐酸性无大差异。其最适pH依次为6.2、5.7、5.7,pH8时的生长量相当最适pH时的84、50、38％。香橙很有希望在四川作pH>6.5的紫色土柑桔园的砧木。pH4时的生长量依次相当最适pH时的74、71、67％,枳仍是酸性土壤的最优砧木。

1-year old 'Valencia' orange [Citrus sinensis Osbeck] trees on different rootstocks were planted and grew for 30 months in the planting-furrows filled with calcareous purple soil, that contained CaCO_3 1.0% and was pH7.6, collected from Chongqing city, Sichuan province. The soil was regulated to different soil pH from 3.5 to 9.0 with H_2 SO_4 and CaO. These were 12 kinds of soil pH and filled into 12 furrows respectively. The soil was sampled from each furrow and analysed four times during the studying. The real soil pH in each furrow were 4.0, 4.1, 4.1, 4.3, 4.6, 4.8, 6.5, 6.9, 7.5, 7.7, 7.9, 7.9, respectively. The average soil volume per tree was about 60 × 80 × 60cm. The rootstocks used were trifoliata orange [Poncirus trifoliata Raf. ], Hong-ju [Citrus reticulata Blanco.] and Xiang-chen [C. junos Tanaka.]. The effects of soil pH on iron absorbing ability, chlorophyll contents, the activity of peroxidase and the amounts of plant growth of 'Valencia' orange on different rootstocks were studied. The results indicated that the order in tolerance to alkaline soil among these citrus rootstocks was Xiang-chen, Hong-ju and trifoliata orange. The difference in ability of tolerance to acid soil was not obvious in our studies. The most adaptive soil pH was 6.2, 5.7, and 5.7 respectively. The precentages of total fresh weight per plant at the end of study in pH 8.0 to the most adaptive soil pH was 84% on Xiang-chen, 50% on Hong-ju and 38% on trifoliata orange and that in pH 4.0 was 74%, 71% and 67% respectively. It was promised that Xiang-chen would be the better citrus rootstock in calcareous soils.Trifoliata orange is already the best citrus rootstock in acid soils.