论文部分内容阅读
通过盆栽试验方法,采用13C脉冲标记技术和稳定同位素质谱分析技术,研究了三个生育期(返青期、分蘖期和抽穗期)光合碳在“水稻-土壤”系统中的同化率、分配比率及其在土壤中增加率的动态变化,探讨三个生育期光合碳在“水稻-土壤”系统中的运转、分配规律,为明确稻田生态系统中碳素循环过程提供理论依据。结果表明,分别在返青期、分蘖期和抽穗期进行一次13C脉冲标记(持续5 h)后,光合碳在“水稻-土壤”系统中的总同化率均随标记后天数的延长呈逐渐下降趋势,从标记后2 d至收获时,总同化率分别为75.92%~39.53%、70.01%~52.02%、86.38%~69.60%,且收获时与2 d时的同化率差异均达显著水平(p<0.05),其被同化光合碳的损失率分别为47.93%、25.70%和19.43%;抽穗期光合碳同化率明显高于返青期和分蘖期,被同化光合碳的损失也明显低于返青期和分蘖期。三个生育期被同化的光合碳向水稻地上部分和地下部分(包括根和土壤)的运转呈互相消长关系,但向水稻地上部分的分配比率(平均为85.04%~73.10%)远大于向根的分配比率(平均为12.50%~22.04%)和土壤的分配比率(平均为1.70%~5.04%),且抽穗期光合碳向水稻地上部分中的分配比率大于分蘖期和返青期,向地下部分的分配比率则正好相反;此外,三个生育期被同化的光合碳在土壤中的增加率分别为0.08%~0.21%、0.09%~0.17%和0.19%~0.27%,抽穗期土壤中光合碳的增加率要大于返青期和分蘖期,且光合碳在土壤中也相对稳定。
The assimilation rate and distribution of photosynthetic carbon in “paddy-soil” system at three growth stages (turning green stage, tillering stage and heading stage) were studied by pot experiment, 13C pulse labeling and stable isotope mass spectrometry Ratio and its rate of increase in soil, and discussed the rules of photosynthetic carbon movement and distribution in the “paddy-soil” system during the three growth stages in order to provide a theoretical basis for clarifying the carbon cycle in paddy field ecosystem. The results showed that the total assimilation rates of photosynthetic carbon in the “paddy-soil” system were all gradually increased with the number of days post-labeling prolonged after a 13C pulse (at 5 h) at turning-back, tillering and heading stages The total assimilation rates were 75.92% -39.53%, 70.01% -52.02% and 86.38% -69.60% respectively from the 2nd day after the marker to the harvest, and the difference of the assimilation rate at the time of harvest and the 2nd day reached the significant level (p <0.05). The loss rates of assimilated photosynthetic carbon were 47.93%, 25.70% and 19.43%, respectively. The photosynthetic carbon assimilation rates at heading stage were significantly higher than those at turn-back and tillering stages, Turn green and tillering stage. The photosynthetic carbon assimilated into the three growth stages showed a reciprocal relationship with the growth of aboveground and underground parts of rice (including roots and soil), but the distribution ratio to the aerial parts of rice was 85.04% ~ 73.10% (Average from 12.50% to 22.04%) and soil allocation rate (from 1.70% to 5.04% on average), and the distribution ratio of photosynthetic carbon to aerial parts of rice at heading stage was greater than that at tillering stage and turning green stage, In addition, the photosynthetic carbon assimilation rates in the three growth stages were 0.08% -0.21%, 0.09% -0.17% and 0.19% -0.27%, respectively. During the heading stage, photosynthetic carbon Of the increase rate is greater than turning green and tillering stage, and photosynthetic carbon is also relatively stable in the soil.