Manandhar Anju, Sinclair Thomas R, Rufty Thomas W, Ghanem Michel E
Crop and Soil Sciences Department, North Carolina State University, Raleigh, NC, 27695-7620, USA.
Department of Physiology, International Center for Agricultural Research in the Dry Areas (ICARDA), Rabat, Morocco.
Physiol Plant. 2017 Jun;160(2):201-208. doi: 10.1111/ppl.12544. Epub 2017 Mar 7.
Drought can result in severely decreased leaf area development, which impacts plant growth and yield. However, rarely is leaf emergence or leaf expansion separated to resolve the relative sensitivity to water-deficit of these two processes. Experiments were undertaken to impose drought over approximately 2 weeks for eight cowpea (Vigna unguiculata) genotypes grown in pots under controlled environmental conditions. Daily measures of phyllochron index (PI, leaf emergence) and leaf area increase (leaf expansion) were obtained. Each of these measures was referenced against volumetric soil water content, i.e. fraction transpirable soil water. Although there was no clear difference between leaf emergence and leaf expansion in sensitivity to drying soil, both processes were more sensitive to soil drying than plant transpiration rate. Genotypic differences in the soil water content at the initiation of the decline in PI were identified. However, no consistent difference in sensitivity to water-deficit in leaf expansion was found. The difference in leaf emergence among genotypes in sensitivity to soil drying can now be exploited to provide guidance for plant improvement and crop yield increase.
干旱会导致叶面积发育严重减少，从而影响植物生长和产量。然而，很少将叶片出现或叶片扩展分开来解析这两个过程对水分亏缺的相对敏感性。在可控环境条件下，对盆栽的8个豇豆（Vigna unguiculata）基因型进行了约2周的干旱处理实验。每天测量叶龄指数（PI，叶片出现）和叶面积增加（叶片扩展）。这些测量结果均以土壤体积含水量，即可蒸腾土壤水分分数为参照。虽然叶片出现和叶片扩展对土壤干燥的敏感性没有明显差异，但这两个过程对土壤干燥的敏感性均高于植物蒸腾速率。确定了PI下降开始时土壤含水量的基因型差异。然而，未发现叶片扩展对水分亏缺的敏感性存在一致差异。现在可以利用基因型间叶片出现对土壤干燥敏感性的差异，为植物改良和作物增产提供指导。
