大气二氧化碳浓度与温度升高对红桦幼苗养分积累和分配的影响

Effects of elevated CO_2 concentration and temperature on nutrient accumulation and allocation in Betula albo-sinensis seedlings

利用封闭式生长室,研究了CO2浓度升高(环境CO2+350μmol.mol-1,EC)、温度升高(环境温度+2℃,ET)以及二者同时升高(ECT)对川西亚高山红桦幼苗养分积累和分配的影响.结果表明:经过一个生长季,EC处理下红桦幼苗单株N、P、K积累比对照分别增加44%、45%和11%(P<0.05),ET处理下分别增加37%、76%和9%(P<0.05),ECT处理下分别增加24%、88%和20%(P<0.05).EC处理使N向红桦幼苗叶中分配的比例降低11.68%(P<0.05),向枝、茎、根中分配的比例分别增加2.95%、3.39%和5.34%(P>0.05);ET处理使N向叶中分配的比例增加11.09%(P<0.05),向枝、茎、根中分配的比例分别降低0.69%、10.35%和0.05%(P>0.05).ECT处理下N的分配格局与EC处理相似.3种处理下P和K在红桦幼苗中的分配变化差异较大,CO2浓度和温度升高可能促进植物养分的积累,改变养分在植物各器官间的分配.

With enclosed chamber system, this paper studied the effects of elevated CO2 concentration （ ambient ＋ 350 μmol·mol^-1, Ec ）, temperature （ ambient ＋ 2 ℃, ET ） , and their combination （ ECT ） on the nutrient accumulation and allocation in subalpine Betula albo-sinensis seedlings in western Sichuan Province. The results showed that after a growth season, the accumulation amount of N, P and K per plant increased by 44% , 45% and 11% under Ec （P 〈 0.05） , by 37% , 76% and 9% under ET （P 〈 0. 05 ）, and by 24% , 88% and 20% under ECT（P 〈0.05） , respectively. The N allocation to leaves reduced by 11.68% （ P 〈 0.05 ） under Ec but increased by 11.09% （ P 〈0.05） under ET, while that to branches, stems and roots increased by 2. 95%, 3.39% and 5.34% under Ec （ P 〉 0. 05） , but decreased by 0. 69% , 10. 35% and 0. 05% under ET （ P 〉 0. 05）, respectively. The N allocation pattern under ECT was similar to that under Ec. The allocation of P and K had greater differences under Ec, ET and ECT. All of these suggested that elevated CO2 concentration and temperature could promote nutrient accumulation, and change its allocation pattern in plant organs.