基质供水状况对番茄穴盘苗生物学积累及营养吸收的影响

对番茄穴盘苗进行相对含水量(RWC)分别为90%、75%、60%、45%、30%的供水下限处理,探讨了基质供水状况对其生长及N、P、K营养吸收与分配的影响。结果表明:90%和75%供水下限处理间生物学产量无显著差异,低于75%供水下限时,番茄穴盘苗生物学产量随供水减少而下降。75%供水下限处理的幼苗干物质积累和壮苗指数均最高,根系物质积累对水分变化最为敏感。随供水下限降低,叶、根N含量呈下降趋势,茎N含量受影响较小,较为严重限水时,N含量上升;P含量随供水下限降低逐步减少,茎、叶K 含量随供水减少迅速上升,表现出明显的渗透调节作用;N、P、K吸收总量受水分影响较大,但其在叶、茎、根中的分配比例改变较小。供水减少使番茄K 倾向于茎、叶分配,有助于逆境下进行渗透调节,维持正常代谢。综合幼苗生长发育及营养吸收,初步确定75%的基质相对含水量为番茄穴盘苗适宜的供水下限。

Effect of Water Supply Condition on Biomass Accumulation and Nutrition Metabolism of Tomato Plug Seedlings

Tomato plug seedlings were treated under different condition of water supply in nursery media, and discussed the biomass, nitrogen,phosphate,potassum uptake and the distribution. The results indicated that the seedlings biomass was tended to decrease with water supply decreasing, and the seedlings treated under 75% RWC floor level of water supply was the most desirable. Of all the investigated indexes, root was the most sensitive to media water condition, then leaf and shoot. Under relatively severe water deficit,nitrogen content tended to be up.With decreasing of water supply, phosphate content decreased especially in leaf, shoot whereas potassum content sharply increased in leaf and shoot, showing significant osmotic adjustment. Total nitrogen, phosphate, potassum accumulation were obviously affected by irrigation condition, but distributing proportion among leaf, shoot, root varied a little. Less irrigation made potassum tend to be transported more to shoot, leaf, which favored osmotic adjustment under adversity to keep normal metabolism. In view of biomass yield and nutrient condition, 75% RWC was regarded the proper floor level of water supply for tomato plug seedlings.