Radin J W, Eidenbock M P
United States Department of Agriculture, Agricultural Research Service, Phoenix, Arizona 85040.
Plant Physiol. 1986 Nov;82(3):869-71. doi: 10.1104/pp.82.3.869.
Leaves of cotton (Gossypium hirsutum L.) accumulate considerable dry mass per unit area during photosynthesis. The percentage of C in that accumulated dry mass was estimated as the regression coefficient (slope) of a linear regression relating C per unit area to total dry mass per unit area. Plants were grown on full nutrients or on N- or P-deficient nutrient solutions. In the fully nourished controls, the mass that accumulated over a 9-hour interval beginning at dawn contained 38.6% C. N and P stress increased the C concentration of accumulated mass to 49.7% and 45.1%, respectively. Nutrient stress also increased the starch concentration of accumulated mass, but starch alone could not account for the differences in C concentration. P stress decreased the estimated rate of C export from source leaves, calculated as the difference between C assimilation and C accumulation. The effect of P stress on apparent export was very sensitive to the C concentration used in the calculation, and would not have been revealed with an assumption of unchanged C concentration in the accumulated mass.
棉花（陆地棉）叶片在光合作用过程中单位面积积累了相当可观的干物质。积累的干物质中碳的百分比通过将单位面积碳含量与单位面积总干物质含量进行线性回归的回归系数（斜率）来估算。植株种植在全营养或氮素或磷素缺乏的营养液中。在营养充足的对照植株中，从黎明开始的9小时内积累的物质含碳量为38.6%。氮素和磷素胁迫分别使积累物质的碳浓度增加到49.7%和45.1%。营养胁迫也增加了积累物质的淀粉浓度，但仅淀粉无法解释碳浓度的差异。磷素胁迫降低了源叶中碳的估计输出速率，该速率通过碳同化与碳积累之间的差值计算得出。磷素胁迫对表观输出的影响对计算中使用的碳浓度非常敏感，若假设积累物质中的碳浓度不变则无法揭示这一影响。
