干旱胁迫对砂糖橘树体营养的影响及其与成花的关系

Effects of Drought on Citrus reticulate‘Shatangju’Nutrition Status and Its Relations with Flowering

为了探讨干旱胁迫对砂糖橘(Citrus reticulata ‘Shatangju’)树体营养的影响及营养与成花的关系,设置了不同干旱胁迫时间(0、2、4、6、8周)和不同氮素水平(每次每盆单独施N︰P2O5︰K2O为15︰15︰15的复合肥5g和另外加尿素6g两水平)两因素进行盆栽试验研究。结果表明,干旱胁迫4周后树体氮素和钾素增加,而非结构性碳水化合物糖和淀粉呈下降趋势,磷素无明显变化,树体中C/N,P/N与对照相比降低。各养分含量及相互比率在干旱胁迫4周左右存在一个明显拐点,且与砂糖橘的成花时间表现高度一致。每枝成花数量和氮素及钾素有显著正相关关系,和C/N呈负相关关系,而和树体磷含量无显著相关关系。在正常供水情况下不同营养状况砂糖橘均未成花,但在干旱胁迫情况下氮素、钾素以及C/N和成花特性间有很好的相关关系。

In order to study effects of drought stress on Shatangju tangerine（Citrus reticulate ‘Shatangju’）nutrition status and its relations with flowering,potted culturing experiments were carried out and multi-factorial design was applied with water stress duration（0,2,4,6,8 weeks）and nitrogen fertilization level（5 g compound fertilizer and 5 g compound fertilizer plus 6 g urea per pot）as factors. It was found that nitrogen and potassium levels increased after four weeks of drought stress,compared with control,while nonstructural carbohydrates decreased. Citrus phosphorous content was not significantly influenced. The relative content of nutrition was also affected by drought stress,with citrus C/N and P/N being decreased relatively compared with control. The critical time point for nutrition differentiation was at about four weeks after the initiation of drought stress,which was also coincident with the critical inducting period in flowering exhibition. Flower numbers per shoot had positive correlations with nitrogen and potassium content,but negative correlations with C/N. Phosphorous content did not have significantcorrelations with flowering. Shatangju tangerine did not show any flowering under normal water condition no matter what the nutrition status was,but nitrogen,potassium and C/N had good correlations with flowering properties when drought stress was more than four weeks.