The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of ch...The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of chlorophyll biosynthesis were analyzed in winter wheat cultivars in soil culture, miniblock culture, and solution culture to study the effects of Mo on chlorophyll biosynthesis without Mo addition （CK, soil available Mo 0.112 mg kg^-1） and Mo addition （＋ Mo, 0.13 mg kg^-1 Mo was added）. Laevulinic acid （LA）, the competitive analog of δ-aminolaevulinic acid （ALA） was also introduced in the experiment. The ratio of Chl a/Chl b was constant between CK and ＋ Mo treatment, whereas it increased at low temperature, which indicated that Mo deficiency did not inhibit the transformation of Chl a to Chl b at low temperature. Under Mo deficiency, the contents of protochlorophyll （Pchl）, Mg-protoporphyrin Ⅸ （Mg-Proto Ⅸ）, protoporphyrin Ⅸ （proto IX）, and uroporphyrinogen Ⅲ （Uro Ⅲ） decreased [Uro Ⅲ decreased significantly （P 〈0.01）], whereas ALA and glutamate increased significantly （P 〈 0.01） compared with that of Mo addition, which suggested that the transformation from ALA to Uro Ⅲ might be inhibited. The content of ALA reversed after addition of LA, it was significantly higher （P 〈 0.01） in Mo addition than in CK. The results indicated that the transformation from ALA to Uro Ⅲ was blocked under Mo deficiency, which resulted in the inhibition of the biosynthesis of chlorophyll and led to the decrease of chlorophyll in winter wheat cultivars.展开更多
基金This study was financed by National Natural Science Foundation of China(NSFC,30070431 and 39770428)the Key Project under Nineth Five-Year Plan of China Agricultural Administration(Agriculture 95-18-04).
文摘The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of chlorophyll biosynthesis were analyzed in winter wheat cultivars in soil culture, miniblock culture, and solution culture to study the effects of Mo on chlorophyll biosynthesis without Mo addition （CK, soil available Mo 0.112 mg kg^-1） and Mo addition （＋ Mo, 0.13 mg kg^-1 Mo was added）. Laevulinic acid （LA）, the competitive analog of δ-aminolaevulinic acid （ALA） was also introduced in the experiment. The ratio of Chl a/Chl b was constant between CK and ＋ Mo treatment, whereas it increased at low temperature, which indicated that Mo deficiency did not inhibit the transformation of Chl a to Chl b at low temperature. Under Mo deficiency, the contents of protochlorophyll （Pchl）, Mg-protoporphyrin Ⅸ （Mg-Proto Ⅸ）, protoporphyrin Ⅸ （proto IX）, and uroporphyrinogen Ⅲ （Uro Ⅲ） decreased [Uro Ⅲ decreased significantly （P 〈0.01）], whereas ALA and glutamate increased significantly （P 〈 0.01） compared with that of Mo addition, which suggested that the transformation from ALA to Uro Ⅲ might be inhibited. The content of ALA reversed after addition of LA, it was significantly higher （P 〈 0.01） in Mo addition than in CK. The results indicated that the transformation from ALA to Uro Ⅲ was blocked under Mo deficiency, which resulted in the inhibition of the biosynthesis of chlorophyll and led to the decrease of chlorophyll in winter wheat cultivars.
