施肥对桢楠幼苗光合生理及生长特性的影响

以1年生桢楠(Phoebe zhennan)幼苗为材料,采用盆栽试验方法,选用氮肥(NF)、复合肥(CF)、有机肥(OF)和混合肥(MF)4种肥料,依据年施氮量为标准设置低(L,0.3g/桶)、中(M,0.6g/桶)、高(H,0.9g/桶)3个施肥水平,于5、7、9月分3次将各肥料平均施入各栽植桶中,考察施肥1个月后桢楠幼苗的形态和光合生理指标,探讨施肥对桢楠幼苗光合生理及生长特性的影响。结果显示:(1)3个施肥水平中,中氮水平(M)对桢楠幼苗的生长促进效应最大;各种肥料中又以CF肥效最差,NF的肥效仅在初期(5～6月)比较明显,施MF的后期(9～10月)养分供应相对不足,而OF能持续地为植株提供养分。(2)施肥可以促进桢楠幼苗叶片叶绿素合成,延长绿叶功能期,并增大净光合速率,其中OF和MF的效果更明显,且有效地提高了幼苗在强光照、高浓度CO2环境下的光合能力。(3)除CF以外,施其他3种肥料均能不同程度地增加桢楠幼苗苗高及地径生长量,且以中氮水平的有机肥(MOF)促进效应最大,其生长量可以达到对照(CK,不施肥)的2倍。综上可知,中氮量有机肥是桢楠幼苗的最佳肥料施用方式。

Effect of Fertilization on Photosynthetic Physiology and Growth Characteristics of Phoebe zhennan Seedlings

A pot experiment was conducted to study the effects of application of four fertilizers,nitrogen fertilizer (NF),compound fertilizer (CF),organic fertilizer (OF) and mixed fertilizer (MF),on 1-year-old Phoebe zhennan seedlings.Each fertilizer was applied at three levels based on the annual nitrigen application rate,namely,low (L,0.3 g/pail ),medium (M,0.6 g/pail ) and high (H,0.9 g/pail),which was divided into three equal parts and applied into pail in the middle of May,July and September,respectively.The morphological and photosynthetic indicators of P.zhennan seedlings were measured after a month of fertilization to explore the effects of fertilizer application on photosynthetic and growth characteristics of the seedlings.The results showed that:(1)The medium nitrogen application rate showed the greatest promoting effects on the growth of P.zhennan seedlings for the 3 types of fertilizers,and when comparison was conducted between fertilizer types,CF acted the worst,NF acted well only at early stage (May-June),MF application reflected a relative lack of nutrient in the late phase (September-October),while OF was able to provide nutrients for the seedlings more continuously;(2)Fertilization functioned well in promoting chlorophyll synthesis,extending the functional period of green leaves,and enhancing net photosynthetic rate of P.zhennan seedlings,wherein OF and MF performed more effectively,coupled with the photosynthetic capacity of seedlings improved under an environment of strong light,high CO₂ concentration;(3)In addition to CF,application of other three kinds of fertilizers has increased the height and diameter growth of P.zhennan seedlings to varying degrees,with the greatest stimulation observed in OF at medium application rate (M_OF),which displaying an increment twice as much as that of CK.As can be seen,M_OF is the best choice in the fertilizer management of P.zhennan seedlings.