不同氮素形态对枳橙幼苗生长特性的影响

采用水培方法研究了不同形态氮素配比对枳橙Citrus.sinensis(L.)Osb×Poncirus trifoliate(L.)Raf]幼苗生长特性的影响。结果表明,不同氮素形态配比营养液对枳橙幼苗的生长均有一定的促进作用,其中混合态氮素对植株地上部形态特征的影响好于单一态氮素,NO3-∶NH4+=5∶5处理更利于株高、茎粗和叶片数的增加;其次是NO_3~-∶NH_4~+=7∶3处理;单一态氮素形态处理中,全硝培养好于全铵培养。NO_3~-∶NH_4~+=5∶5处理促进了地下部主根的伸长和侧根的增加,却对主根粗度无明显影响。全铵培养对幼苗地上部和地下部生长均有抑制作用,甚至是毒害作用。不同氮素形态配比对枳橙幼苗叶绿素a、叶绿素b及叶绿素总量的影响趋势基本一致,混合态氮素对叶绿素a、叶绿素b和叶绿素总量的促进好于单一态氮素,且当处理为NO_3~-∶NH_4~+=5∶5时叶绿素含量持续增加,并且更利于其积累;而全铵处理则不利于叶绿素的增加与积累。

Effect of Different Nitrogen Forms on Seedling Growth Characteristics of Citrange

Hydroponic experiments were carried out to study the influences of different ratio of NO3-:NH4+ on the growth char-acteristics of citrange Citrus. sinensis(L.)Osb×Poncirus trifoliate(L.)Raf] seedling. The results showed that all forms and ratio of nitrogen could improve the growth of citrange seedling; while mixed nitrogen was better than single nitrogen; and NO3-:NH4+=5:5 was the optional treatment on seedling height, stem diameter and leaf number, followed by and NO3-:NH4+=7:3. For single nitrogen form treatments, the effect of total nitrate as better than total ammonium. Except for the root diameter, the taproot length and number of fibrous roots were both increased by NO3-:NH4+=5:5 treatment. Both upground and underground growth of seedlings were inhibited, even poisoned by total ammonium. The affecting tendency of different ratio of NO3-:NH4+on the content of chlorophyll a, chlorophyll b and total chlorophyll was consistent. Mixed form of nitrogen had better promo-tion effect on chlorophyll accumulation than single form of nitrogen. Under the treatment NO3-:NH4+=5:5, chlorophyll content increased consistently, which was benefit for its accumulation; while total ammonium was unfavourable for increasing and ac-cumulation of chlorophyll.