Quality and quantity estimation of solor ultraviolet radiation on development of horticultural plants under the unfavorable environmental conditions.

为选育耐恶劣环境条件的蔬菜，以及在不良栽培条件下的实际应用，我们试图评估紫外线在太阳辐射和人工辐射下对蔬菜(萝卜和生菜)生长发育的影响。太阳UV-B的季节变化：每天的UV-B的变化与光合作用的活跃太阳辐射(光合光通量密度：PPFD)的变化非常平行，特别是在晴朗的天气下。阴天的紫外线-B辐射是晴天的30-35%。6月至7月的紫外线-B辐射是11月至12月的2-3倍。研究了400 nm以下紫外线的消除对萝卜(Brrasica campestris L.)发育的影响。在消除400 nm以下紫外线的情况下，乙烯基膜下的裤子在植株长度和叶柄方面优于乙烯基膜…下的裤子在春末夏初这段时间内，紫外线透过率较高。在萝卜植株中添加UV-B，可诱导植株出现青铜色叶片和矮化植株，并强烈抑制植株发育。添加UV-B的单位叶面积的光合作用速率与对照(UVT)差异不显著。以生菜品种Okayama Sarada为试材，研究了UV-B辐射对生菜生长发育和光合作用的影响。用UV-B照射19日龄幼苗，在人工光照(日长10000勒克斯，16小时)下照射1周，照射强度和照射时间发生变化。UV-B辐射对膨大叶片的影响较强，且随叶龄的增加而增强。经UV-B辐射的幼叶变厚，细长，呈深绿色，内部卷曲，并站立起来。暗期间的UV-B对发育的抑制作用比光期强得多。与对照相比，UV-B提高了单位叶面积的最大光合速率、叶绿素含量和花青素含量。较少

For breeding of vegetables tolerant to unfavorable environmental conditions, and its practical application under undesired cultural conditions, we tried to estimate the effect of ultraviolet on the development of vegetables (turnip and lettuce) under the solar radiation and artificial irradiation.1. Seasonal variation of solar ultraviolet-B : The variation of ultraviolet-B per day paralleled strongly that of photosynthetic active solar radiation (photosynthetic photo flux density : PPFD) , especially under fine weather. The ultraviolet-B radiation under the cloudy weather amounted to 30-35% of that under fine weather. The ultraviolet-B radiation between june and july amounted to 2-3 times of that between november and december.2. Effect of elimination of ultraviolet below 400 nm were investigated on the development of turnip (Brrasica campestris L.). Pants under the vinyl film eliminating ultraviolet below 400 nm were superior in plant length and leaf stalk to those under the vinyl film … More transmitting ultraviolet in the experiment between late spring and early summer.3. The supplemented UV-B to turnip plants induced bronzed leaves and dwarfed plants, and suppressed strongly the development of plants. Photosynthetic rate per unit leaf area under the supplemented UV-B was not significantly different from that under the control (UVT).4. Using lettuce (cv.Okayama sarada) , we investigated the effect of UV-B on development and photosynthetic activity. Nineteen day old seedlings were irradiated with UV-B which changed in irradiance and the time of irradiation under the artificial light (10000 Lux 16hr-daylength) for I week. Effect of UV-B was strongly observed on the expanded leaves, and increased with the age of leaves. Irradiated young leaves with UV-B became thcik, slender and dark green, curled inside, and stood up. The UV-B irradiated during dark period surpressed the development much stronger than that during light period. Maximum photosynthetic rate, chlorophyll, and anthocyanine per unit leaf area were increased by UV-B when compared. Less