有机酸在疫霉营养中作用的进一步研究

利用放射性同位素标记的~(14)C-琥珀酸跟踪,进一步证明有机酸在晚疫病菌的营养中作为碳架与铵盐结合而合成菌体的氨基酸,同时也进入三羧酸循环参加呼吸。所以其作用不仅仅是缓冲作用。所试6个生理小种19株国内外晚疫病菌都对有机酸有迫切需要而旺盛生长,只有两株国外菌种长势太弱。其他测试过的疫霉P.boehmeriae,P.capsici,P.cinnamomi,P.citrophthora,P.colocasiae,P.erythroseptica,P.fragariae,P.megasperma f.sp.glycinea,P.palmivora,P.parasitica,P.sinensis和P.syringae 12种包括A_1与A_2交配型共18株菌都对有机酸有需要,只在迫切程度上不同。但有机酸在疫霉属营养上有普遍意义则是显而易见的。

FURTHER STUDIES ON THE NUTRITIONAL EFFECTS OF ORGANIC ACIDS ON SPECIES OF PHYTOPHTHORA

Direct evidence of nutritional effects of organic acids on Phytophthora infestans was obtained by using ~(14)C-succinate as tracer. Organic acid might serve as a precursor of the primary amino acid. In mycelial hydrolysate, the amino acids of aspartic acid family showed high radioactivity. ~(14)CO_2 collection proved that organic acid had participated in respiration. Nineteen strains of Phytophthora infestans belonging to six races collected from our own country and abroad gave similar response to organic acids. Except two foreign strains, all the other strains grew luxuriantly. Eighteen strains of twelve other species tested, namely, P. boehmeriae, P. capsici, P. cinnamomi, P. citrophthora, P. colocasiae, P. erythroseptica, P. fragariae, P. megasperma f. sp. glycinea, P. palmivora, P. parasitica, P. sinensis and P. syringae, including A_1 and A_2 mating types required organic acid for luxuriant growth, but the degree of growth-promoting effect differed with different strains. However, the beneficia effect of organic acid on growth of Phytophthora species is obvious.