利用^(14)C研究檫树苗根系分泌物

Study on Root Exudates of Sassafras tzumu Seedling Using Carbon 14

檫树苗进行 14 CO2 喂饲后 ,培养于不同培养液中 ,同时动态测定苗木体内光合产物分配和根系分泌物数量 ,并对分泌物进行分离 .结果表明 :在标记后 1 5d内营养液和蒸馏水 2种培养处理苗木叶子中光合产物含量比例分别从 67.42 %下降至 35.0 8%和 34.50 %,而新梢和根中光合物比例分别上升了 1 0 .87%、1 4.5%和 1 7.60 %、 1 2 .68%.檫树苗根系分泌物分泌高峰出现在标记结束后第 3～ 5天 ,以后逐渐减少 ,动态测定的 1 0 d中蒸馏水培养处理分泌累积量一直大于营养液处理的量 ,它们 1 0 d中总共分泌量分别是 50 51 3和 45586dpm·株-1.从分泌物分离来看 ,2种处理檫树苗分泌物中都是糖类占优势 ,分别达到了 60 .0 3%(营养液培养 )和 59.70 %(蒸馏水培养 ) ,其次是有机酸 ,氨基酸占的比例最低 ,2种处理分别仅为 1 8.37%和 1 9.87%

Sassafras tzumu seedlings were fed with carbon 14 and cultured in distilled water and nutritive solution respectively. During the period of culturing, distribution of photosynthates and root exudates in amount and in composition were detected everyday. The results are following: When 15 days after feeding, the photosynthesis production in seedling leaves reduced from 67.42% to 35.08% (in nutritive solution) and to 34.50% (in water), however, in new shoots and roots the photosynthesis production respectively increased by 10.87% and 14.5% (in nutritive solution),by 17.60% and 12.68% (in water).The summit of exudating occurred 3~5 days after labeling, afterwards, reducing gradually with time. During 10 days culturing, root exduades in accumulative amount is always more in water with sum 50 513 dpm per seedling than in solution with sum 45 586 dpm per seedling. Sugar is the main root exudate(60.03% in solution,59.70% in water), the organic acids the second, and amino acids is the least.