土壤水分和氮磷营养对冬小麦根苗生长的效应

在模拟田间原状土容重的条件下土培，研究了土壤水分和氮磷营养对小麦根苗生长及水分利用的效应。结果表明：在ＳＲＷＣ为４０％－７０％范围内，土壤水分亏缺严重，ＲψＷ和ＥＴ显著降低，根苗生长严重受阻，ＲＬ变短，ＲＤＷ降低，ＬＡ和ＰＤＷ减少；随着土壤水分趋于良好，ＲψＷ、ＥＴ和ＬＡ明显增加，ＲＤＷ和ＰＤＷ在ＳＴＷＣ为５５％－６２％之间时最大，而ＳＲＷＣ在５５％上下时ＲＬ达最长；土壤轻度干旱有利根系下扎，土壤

Effects of Soil Water, Nitrogen and Phosphorus Supplied on Root and Seedling Growth of Wheat

2 pot experiments each with 6 treatments and 8 replications were conducted in order to study the effects of soil moisture, nitrogen and phosphorus supplied on root and seedling growth of wheat. A wheat cultivar Xiaoyan 6 was used. Results showed that under soil relative water content (SRWC) 40%-70%, as SRWC decreasing, root and seedling growth of wheat are inhibited, root water potential (Rw), leaf area (LA), evapo-transpiration (ET), root length (RL), root dry weight (RDW) and plant dry weight (PDW) are obviously declining. SRWC increases, Rw LA and ET increase obviously, but RL, RDW and PDW is a curve response, the maximun can be reached when SRWC is 55%-62% for RDW and PDW, and 55% for RL, respectively. Nitrogen and phosphorus supplied have very fine adjustment effect on root and seedling growth of wheat. Phosphorus can remarkably raise Rw, RL, RDW, ET, LA, PDW and WUE, especially under the condition of serious water stress. The effect of nitrogen is different from that of phosphorus. Under serious water stress with nitrogen supplied, Rw, ET and LA decrease, showing negative action; but no obvious action under light drought, and positive action under soil water enough. It is of benefit to RDW and PDW to enhance application of nitrigen and phosphorus as SRWC increasing. Phosphorus supplied can strenghten droughtre-sistance of wheat seedling, therefore, it must be taken into account in upland field.