磷有效性对大豆根冠中碳分配的影响

在水培条件下,研究不同浓度磷影响大豆根冠中碳分配的结果表明：磷有效性对大豆根冠中碳分配的影响依赖于磷浓度与胁迫时间。磷浓度高于0．125mmol．L^-1或低磷胁迫7d以内,大豆根冠中碳分配受到的影响不显著。低磷胁迫14d的大豆的净光合速率和根呼吸速率均显著下降,根冠比显著提高。这显示长期低磷胁迫下大豆碳同化总量和根呼吸消耗的碳量虽然减少,但根系生长的碳消耗则增加,光合碳同化形成的碳水化合物向根部的分配是受到促进的。

Effects of Phosphorus Availability on Carbon Allocation between Shoots and Roots in Soybean

Effects of phosphorus （P） availability on carbon （C） allocation between shoots and roots in soybean were studied in hydroponics, The results showed that the effects of P availability on C allocation between shoots and roots in soybean mainly depended on P concentration and duration of P deficiency. P concentration higher than 0.125 mmol.L -~ or duration of P deficiency shorter than 7 days could not affect the C allocation between shoots and roots. But the net photosynthetic rate, root respiration rate of soybean decreased 14 days after P stress and resulted in increased root/shoot ratio. Therefore, long-term P deficiency could reduce the total amount of C assimilation and C cost on root respiration, but increase the C cost on root growth so as to facilitate the C allocation to roots from photosynthetic C source.