Whiley A W, Schaffer B, Lara S P
University of Florida, Tropical Research and Education Center, 18905 S.W. 280 Street, Homestead, Florida, USA.
Tree Physiol. 1992 Jul;11(1):85-94. doi: 10.1093/treephys/11.1.85.
Net efflux of CO(2) from attached avocado (Persea americana Mill.) fruit was measured periodically from three weeks after anthesis to fruit maturity. Net CO(2) exchange was determined in daylight (light respiration, R(l)) at a photosynthetic photon flux (PPF) greater than 600 micromol m(-1) s(-1), and in the dark (dark respiration, R(d)). Dark respiration and R(l) were highest during the early cell division stage of fruit growth (about 25 and 22 nmol CO(2) g(dw) (-1) s(-1), respectively) and decreased gradually until fruit maturity to about 1 and 0.5 nmol CO(2) nmol CO(2) g(dw) (-1) s(-1), respectively. Fruit photosynthesis, calculated from the difference between R(d) and R(l), ranged from 0.5 to 3.1 nmol CO(2) g(dw) (-1) s(-1). Net rate of CO(2) assimilation on a fruit dry weight basis was highest during the early stages of fruit growth and reached the lowest rate at fruit maturity. Net rate of CO(2) assimilation of fruit exposed to light was 0.4 to 2.5% of that for fully expanded leaves. Although the relative amount of carbon assimilated by the fruit was small compared with the total amount of carbon assimilated by the leaves, the data indicate that avocado fruit contribute to their own carbon requirement by means of CO(2) assimilated in the light.
从花期后三周至果实成熟期间，定期测定附着的鳄梨（Persea americana Mill.）果实的二氧化碳净外排。在光合光子通量（PPF）大于600 μmol m⁻² s⁻¹的日光下（光呼吸，R(l)）以及黑暗中（暗呼吸，R(d)）测定净二氧化碳交换。在果实生长的早期细胞分裂阶段，暗呼吸和R(l)最高（分别约为25和22 nmol CO₂ g(dw)⁻¹ s⁻¹），并逐渐下降，直至果实成熟时分别降至约1和0.5 nmol CO₂ g(dw)⁻¹ s⁻¹。根据R(d)与R(l)的差值计算得出的果实光合作用范围为0.5至3.1 nmol CO₂ g(dw)⁻¹ s⁻¹。以果实干重为基础的二氧化碳同化净速率在果实生长早期最高，在果实成熟时达到最低速率。暴露于光下的果实的二氧化碳同化净速率为完全展开叶片的0.4%至2.5%。尽管与叶片同化的总碳量相比，果实同化的碳的相对量较小，但数据表明鳄梨果实通过在光下同化二氧化碳来满足自身的碳需求。
