低磷胁迫对赤皮青冈幼苗生长及生物量的影响

Effects of low phosphorus stress on seeding growth and biomass of Cyclobalanopsis gliva

为研究赤皮青冈生长和生物量分配对低磷胁迫的响应情况,本文以通道县1、2年生赤皮青冈幼苗为试验材料,采用水培法控制营养液中的磷浓度,设置了1.000、0.500、0.100、0.050、0.010、0.005、0.001、0 mM(CK)共8个不同的磷浓度梯度开展试验。研究发现,低磷胁迫下赤皮青冈幼苗能够通过调节自身生长和生物量的分配来适应环境。随着低磷胁迫程度的加强,赤皮青冈幼苗苗高和地径生长受抑制加重,赤皮青冈幼苗的总生物量累积减少,表明在低磷环境下,赤皮青冈幼苗通过降低自身生长和生物量增量来减少对磷元素的消耗。赤皮青冈幼苗的根冠比随低磷胁迫程度的加强而增加,0 mM浓度与对照(1 mM)相比,使1、2年生赤皮青冈幼苗根部生物量增量占总生物累积的百分比分别提高了33.76%和33.19%,表明在低磷环境下,赤皮青冈幼苗将有限的资源优先分配给根系,使根系充分吸收有限的磷元素来维持自身地上部分的生长。

In order to investigate the response of growth and biomass distribution of Cyclobalanopsis gliva to low phosphorus stress,the changes of growth,biomass accumulation and distribution of the seedlings,the annual and biennial seedlings collected from Tongdao County were used as experimental materials.The hydroponics was used to control phosphorus concentration in nutrient solution,and eight phosphorus concentration gradients of 1mM(CK),0.5,0.1,0.05,0.01,0.005,0.001 and 0 were set,respectively.It was found that the seedlings could adapt to the low phosphorus stress by adjusting their own growth and biomass distribution.With the increase of low phosphorus stress degree,the inhibition on height and ground diameter growth of the seedlings increased,and the total biomass accumulation of the seedlings decreased,indicating that the seedlings reduced the consumption of phosphorus by reducing their own growth and biomass increment in low phosphorus environment.The root shoot ratio of the seedlings increased with the low phosphorus stress degree increasing.Compared with the control(1 mM),the percentage of the root biomass increment of annual and biennial seedlings at 0 mM of low phosphorus stress intotal biological accumulation increased by 33.76%and 33.19%,respectively,indicating that seedlings would preferentially allocate limited resources to the root systemin order to ensure the sufficient absorption of limited phosphorus by roots to maintain the growth of above-ground parts in low phosphorus environment.