【摘要】 在固体基质培养条件下,比较了不同形态氮源(硝态氮和铵态氮)及其配比对脐橙生长发育和叶片矿质元素含量的影响.结果表明:1)不同形态氮素对脐橙根系生长、发枝与枝梢生长以及叶片矿质元素含量都具有十分显著的影响.以铵态氮为惟一氮源的植株,其地上与地下部生长均较以硝态氮为惟一氮源的植株差;根系与叶片中积累的NH+4量也以前者明显高于后者,并伴随出现根系腐烂、叶片的叶尖与叶缘枯萎等NH4+毒害症状.2)适当浓度的硝态氮和铵态氮配比对地上地下部生长具有显著的促进作用,比单独使用硝态氮效果更好,两者的浓度比以2∶1为最佳.3)在氮素浓度不变的情况下,随营养液中NH+4的增多与NO3?的减少,叶片中的N,P,Fe含量显著增加,其相关系数分别为0.9716,0.9012,0.9689,达极显著水平,而叶片中Ca,Mg,B的含量则显著减少,相关系数分别为-0.8152,-0.8448,-0.6259,达显著水平.叶片中元素Mn,Cu和Zn的含量呈上升趋势,而K的含量则呈现出先升后降的趋势.更多还原

【Abstract】 The effects of different forms of nitrogen NO3- - N,and its NH4+ - N and ratios on the growth of navel orange seedlings,the mineral nutrition,were determined by sand culture experiment.The results indicated that nitrogen forms had a remarkable effect on the growth of root,sprouting and new flushes,and mineral elements contents in leaves of navel orange seedlings.The growth of plants treated with nitrate nitrogen ( NO3- - N) nutrition was better than that of the plants treated with ammonium nitrogen ( NH4+ - N) nutrition.The NH+4 contents accumulated in roots and leaves of plants in latter treatment were much higher than that of plants in the former treatment,and accompanied with NH+4 poison symptoms of root decay and leaf scorch in the areas of leaf apex and margin. Proper ratio of NH+4 - N to NO3- - N had significantly promoted the growth of seedlings. The growth of plants treated with nitrogen source of both NH4+ - Nand NO3- - N was better than that of plants treated with single nitrogen source NH4+ - N or NO3- - N. The appropriate ratio of NH+4 - N to NO3- -N is 1∶2.The results also showed that increasing ratio of NH+4 - N to NO3- - N in nutrition solution which keeps constant total nitrogen concentration could increase the contents of N,P and Fe in leaves significantly,which conformed to positive correlation,and its coefficient were 0.9716,0.9012 and 0.9689 respectively at 0.01 level.The contents of Ca,Mg and B,however,decreased linearly with increase of ratio of NH4+ - N to NO3- - N, and the coefficient of correlation were -0.8152,-0.8448 and -0.6259 respectively at 0.05 level.The contents of Mn,Cu and Zn tended to go upward and that of K tended to go upward at first then downward with the ratios of NH4+ - N to NO3- - N higher.更多还原