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及其在恶劣栽培条件下的实际应用，我们尝试在太阳辐射和人工照射下评价紫外线对蔬菜（芜菁和莴苣）生长发育的影响。太阳紫外线- b的季节变化：日紫外线- b的变化与光合有效太阳辐射（光合光通量密度：PPFD）的变化高度平行，特别是在晴朗天气下。多云天气下的紫外线- b辐射约为晴天的30-35%。6 - 7月的紫外线辐射是11 - 12月的2-3倍。研究了400 nm以下紫外线对萝卜生长发育的影响。在晚春至初夏期间的试验中，乙烯基膜下去除400 nm以下紫外线的植株长度和叶柄均优于乙烯基膜下的植株。UV-B对芜菁植株有诱导褐变和矮化的作用，对植株发育有明显抑制作用。3 .补充UV-B后，单位叶面积光合速率与对照（UVT）无显著差异。使用生菜(cv。Okayama sarada)，我们研究了UV-B对发育和光合活性的影响。用UV-B照射19日龄幼苗，在10000勒克斯16小时的人工光照下照射1周，辐照强度和照射时间发生变化。UV-B对膨大叶片的影响明显，且随叶龄增加而增强。经UV-B照射后，嫩叶变厚、变细、变墨绿色，叶内卷曲、直立。暗期的UV-B对发育的抑制作用明显强于光照期。最大光合速率、叶绿素和单位叶面积花青素均增加。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