论文部分内容阅读
在温室条件下 ,应用整株植物长期吸收的营养液培养方法研究杨树无性系根系吸收H2 PO4- 动力学特性及其与磷营养效率的关系 ,以揭示杨树不同无性系间磷营养效率差异的机理。结果表明 ,高效型无性系S1 7、S1 9和 1 0 5根系对H2 PO4- 离子的吸收能力明显强于低效型无性系 1 0 6、797、Ⅰ -69、1 3 88和 3 2 44。与低效型无性系相比 ,S1 7、S1 9和 1 0 5具有较小的米氏常数Km 和吸收临界浓度Cmin,说明它们的根系对H2 PO4- 的亲合力、对低磷浓度的耐受能力较强。在缺磷胁迫条件下 ,S1 7、S1 9和 1 0 5根系系统对H2 PO4- 的亲合能力可增加 2 0 %以上 ,其Km 值分别从 1 3 8、1 3 4和 1 4 0 μmol·L- 1 下降到 1 0 1、1 0 7和 1 1 2 μmol·L- 1 ,而低效型无性系的亲合力则变化很小 ,增加不足 5 %。同样 ,高效型无性系对低磷的耐受能力可增加 85 %以上 ,其Cmin 分别从2 5 5、2 94和 2 68μmol·L- 1 下降到 0 3 0、0 3 5和 0 40 μmol·L- 1 ,但低效型无性系的增加均不足 1 5 %。杨树无性系在根系吸收H2 PO4- 动力学特性方面的不同是其磷营养效率差异的重要原因之一。最大吸收速率Vmax,作为根系吸收动力学参数之一 ,对阐明杨树无性系磷营养效率的作用尚不够确定。
Under greenhouse conditions, the long-term absorption of whole plant nutrient solution culture method was used to study the kinetic characteristics of H2 PO4-uptake by poplar clones and its relationship with phosphorus nutrient efficiency, so as to reveal the differences in phosphorus nutrient efficiency among poplar clones The mechanism. The results showed that the uptake of H2 PO4- in S1 7, S1 9 and 105 lines of high-efficiency clones was significantly higher than that of low-efficiency clones 106,797, Ⅰ -69,1 3 88 and 3 2 44 . Compared with the low-efficiency clones, S1 7, S1 9 and 105 had a smaller Km and an absorption critical Cmin, indicating that their roots had affinity for H2 PO4-, resistance to low phosphorus concentrations By ability. Under phosphorus deficiency stress, the affinity of S1 7, S1 9 and 105 lines for H2 PO4- could be increased by more than 20%, and their Km values increased from 138, 104 and 120 μmol L -1 decreased to 1 0 1 0 7 and 1 1 2 μmol·L -1, while the affinity of low-efficiency clones changed little, less than 5%. Similarly, the tolerance of high-efficiency clones to low-P could be increased by more than 85%, and the Cmin decreased from 25 5,2 94 and 2 68 μmol·L -1 to 0 30 0 35 and 0 40 μmol · L-1, but less efficient clones increased by less than 15%. Poplar clones in the root absorption H2 PO4-kinetic characteristics of the difference is one of the important reasons for the difference in phosphorus nutrient efficiency. The maximum absorption rate, Vmax, as one of the root absorption kinetic parameters, is not yet clear enough to elucidate the phosphorus nutrition efficiency of poplar clones.