【摘要】 以兴安落叶松幼苗为研究材料,采用水培试验方法,研究不同NH4+—N与NO3-—N配比对落叶松幼苗生长的影响。结果表明,落叶松幼苗在以NH4+—N为主的营养液中生长较好。营养液中NO3-—N比增加,则幼苗生长下降,过量的NO3-—N可抑制幼苗根系生长,降低幼苗的地下部与地上部干质量比。营养液中NH4+—N的比例增加,植株体内P的浓度也增加,但K的浓度下降。幼苗对NH4+—N的吸收量大于NO3-—N。NH4+—N与NO3-—N配比显著影响营养液的pH值:NH4+—N比例增加,营养液的pH值下降;NO3-—N比例增加,营养液的pH值升高。NH4+—N引起营养液pH值下降的程度大于NO3-—N引起pH值增加的幅度。更多还原

【Abstract】 An experiment was conducted to study the effects of NH4+ -N,NO3- -N and their different supply ratios on the growth of Larix gmelinii seedlings by water culture system in greenhouse.Results showed that L.gmelinii seedlings grew better at higher NH+4-N concentration.The growth of seedlings declined with increasing ratio of NO3- -N.Excessive NO3- -N inhibited root growth and the root/shoot ratio of the seedlings significantly decreased as the NH4+ -N/NO3- -N ratio was over 75%.Increasing NH4+ -N ratio in nutrient solution led to the increase of phosphorus content and the decrease of potassium content in plant tissues.The pH value of the culture medium was affected markedly by the ratio of NH4+ -N to NO3- -N,which decreased with increasing NH4+ -N and increased with increasing NO3- -N.更多还原