钾元素不同供应水平下玉米叶片的生长与发育

采用沙培法,以玉米品种V1和V2为试验材料,定量分析缺钾对玉米生长和发育的影响.从胚芽鞘叶完全展开时,设置营养液中钾的浓度为3个梯度,分别为KH＝8 mmol·L-1;KM＝4 mmol·L-1;KO＝0 mmol·L-1.从胚芽鞘叶完全展开到吐丝期经常浇这3种营养液.用有效积温来计算玉米生长期间所需热量,把每日完好的叶面积作为玉米生长的衡量指标;每天记录每株玉米的叶片数,不管叶片的大小,作为衡量植株生长发育的方法.在每一个钾元素供应水平上,品种V1和V2的叶片数和自播种以来的受热时间呈直线相关.在KO水平上,V1和V2的发育速率分别是10%和15%,相对于KH水平来说是低的.在11片叶子期间,KO水平上的叶面积大约比KH水平上的低46%,KM水平上的叶面积大约比KH水平上的低25%;在玉米抽雄期,KO水平上的叶面积相对于KH来说减少37%,比KM水平上的少26%.这种差异从抽穗期开始一直保持到吐丝期.

Leaf growth and development of maize in response to K supply

The present study was contemplated to quantitatively determine and to separate the effects of potassium deficiency on growth and development of a maize plant.Maize varieties V1 (Sadaf) and V2 (Sultan) were grown in a sand culture.When the coleoptile leaf was fully expanded,three level of K supply i.e. KH=8 mmol·L-1;KM=4 mmol·L-1 and KO=0 mmol·L-1 were established by varying K concentration in the Long Ashton nutrient solution.The supply of respective nutrient media was maintained from coleoptile leaf stage through silking.A thermal time in growing degree days (GDD) was calculated to characterize the thermal environment of the corn plants.The leaf area was estimated daily non-destructively as a measure of growth of a maize plant.Number of leaves per plant,irrespective of a leaf size and the number of leaves per plant in Haun scale were used as a measure of development of a plant and were also recorded on daily basis.There was straight-line linear relationship between the number of leaves of V1 and V2 and the thermal time since sowing for each level of K supply.The development rate of V1 and V2 in KO level was 10% and 15%,respectively slower than that in KH level.At leaf stage 11,the leaf area in KO was about 46% less than the leaf area in KH;and the leaf area in KM was about 25% less than the leaf area in KH supply.At the stage of tasseling,the leaf area in KO was about 37% less compared to KH and 26% less than the leaf area in KM.The differences established in the size of leaf area by the differential supply of K at the tasseling stage were maintained at the silking stage.