马尾松不同种源P素吸收动力学特征

通过水培试验研究田间试验下对P肥反应存在显著差异的5个马尾松种源在3种P水平(水培试验中为0、5、20μmol·L-1)下根系P素吸收总量、离子动力学参数(Imax、Km和Cmin)等特征。研究表明,随着溶液P素浓度的升高,马尾松各参试种源的苗高生长、P素吸收总量均有不同程度的增加,但其变化因种源而异。福建武平和广东信宜两种源对P素增加的反应敏感性(高生长和P素吸收增长率)远低于其他3个参试种源,与大田P肥试验结果一致。对1年生和半年生水培幼苗离子动力学参数测定结果揭示,随着培养溶液P素浓度的升高,各参试种源的Imax下降,Km和Cmin增加。比较分析发现,低P水平下广东信宜和福建武平两种源具有相对较小的Km和Cmin,相对较大的Imax,对分布于武夷山脉南端的福建武平种源尤其如此。

Kinetics of Phosphorus Uptake by Different Provenances of Masson Pine under Low Phosphorus Stress

Liquid culture at 3 phosphorus levels was conducted to illustrate P uptake and its kinetic parameters including I_max, K_m and C_min for five provenances of masson pine which showed different responses to phosphate fertilizer in the field trials.The results indicated that height growth and the amount of P uptake increased diversely with phosphorus raise for the provenances tested.However,the change patterns both in height growth and P uptake varied with provenances,among which Wuping of Fujian and Xinyi of Guangdong showed less sensitivity to phosphorus,compared with other three provenances.This result was similar to those from field trials.The kinetics experiments of phosphorus uptake by 0. 5 or 1-year-old seedlings drew the conclusion that,with the amelionation of phosphorus given,the I_max decreased while K_m and C_min increased in all provenances.Under low phosphorus stress,Xinyi of Guangdong and Wuping of Fujian had relatively smaller K_m and C_min,and higher I_max,especially for the latter which distributed in the southern region of Wuyi Mountain.