增强的紫外线-B辐射对几种作物和品种生长的影响

在温室条件下，以每日2．2kJ／m^2(CK)、8．82kJ／m^2(T1)和12．6kJ／m^2(T2)紫外线-B辐射(UV-B，280～320nm)剂量研究了5个黄瓜(Cucumis satious L.)品种，7个番茄(Lycopsicon esculentum Mill)品种及大豆Glycine max(L.)Metr．]、菜豆(Phaseolus vulgaris L.)和黄河密瓜(Cucumis melo L.)的生长反应。辐射处理25d后，测定了株高(PH)、叶重(LDW)及总生物量(TDW)、叶面积(LA)、特定叶重(SLW)、上胚轴长度(EL)和番茄品种的子叶节周长(GCN)。结果表明，种间和种内差异显著。但是大多数品种及种的反应指数为负值，并呈现强度负相关效应，说明UV—B辐射抑制了它们的生长发育，但大豆的反应指数在低剂量的处理下为正值反而促进其生长。UV—B胁迫下，大多数种类的上胚轴延伸明显受阻，特定叶重增加，叶面积和生物量减少，番茄的子叶节膨大。作物对UVB辐射的种内和种间反应是作物遗传特性上的差异和对环境的适应能力不同所致。

Effects of enhanced UV-B radiation on the growth of some crops

Five cucumber cultivars(Cucumis sativus L.),seven tomato cultivars (Lycopsicon esculentum Mill.),soybean［Glycin max(L.)Merr.］,bean(Phaseolus vugaris L.)and watermelo(Cucumis melo L.cv.huanghemi)were investigated on their growth responses to simulating enhanced ultraviolet-B(UV-B,280～320nm)radiation(T1=8.82kJ/m2.d，T2=12.6kJ/m2.d and CK=2.2kJ/m2.d)under greenhouse conditions.After 25 days,leaf area(LA),leaf dry weight(LDW),total dry weight (TDW),plant height(PH),special leaf weight(SLW),epicotylar length(EL),girth of cotyledonary node(GCN)were measured.The results indicated that intraspecific and interspecific difference were significant.Enhanced UV-B radiation induced changes in morphological character,the reduction of biomass,plant height and leaf areas,the increase of special leaf weight and the inhibition of epicotylar growth.and finally lead to the reduction of RI (RI<0).Of the cultivars,Jingchun 3 was the most sensitive to UV-B irradiance compared with other cucumber cultivars and ganfeng 2 more tolerant than other ones.Similarly,the most inhibition to Longfan 3 in tomato cultivars was observed and longfan 7 was more tolerant cultivar.UV-B radiation inhibited the girth of cotyledonary node of tomato cultivars.But Longfan 5 did not show significantly change statistically.It is unclear that the growth of soybean under T1 treatment significantly increased.It could be infered from the results that intraspecific and interspecific difference were due to different morphology,structure,the metabolic levels,hereditary characteristic and adaptive ability to UV-B stress.