Plants must maintain a balance between their carbon (C) supply and utilization during the day–night cycle for continuous growth since C starvation often causes irreversible damage to crop production. It is not well known how C fixation and allocation in the leaves of crops such as maize adapt to sudden environmental changes. Here, to quantify primary C fixation and partitioning in photosynthetic maize leaves under extended darkness and to relate these factors to plant growth, maize seedlings were subjected to extended darkness (ED) for three successive days at the 6th leaf fully expanded stage (V6). ED reduced plant growth and leaf chlorophyll levels but not the rate of net CO₂ exchange. As a result of the reduction in photoassimilates, the accumulation of starch and total soluble carbohydrates (TSC) in mature leaves also decreased under ED. However, the percentage of the daily C fixation reserved in mature leaves increased. These transient C pools were largely composed of TSC and were mainly used for consumption by increased nocturnal respiration rather than for transport. As the days went on, both the amount of C accumulated and the percentage of the daily fixed C that was reserved in leaves decreased, which could be largely accounted for by the attenuated starch synthesis in all treatments. The activities of ADP-glucose pyrophosphorylase and soluble starch synthase decreased significantly over time. Therefore, this study concluded that both starch and TSC are involved in the coordination of the C supply and plant growth under a sudden C shortage but that they may be involved in different ways. While the ratio of reserved C to daily fixed C increased to maintain blade function under acute C starvation, both the amount and the proportion of C reserved in mature leaves decreased as plant growth continued in order to meet the growth demands of the plant.

植物必须在昼夜循环中保持其碳 (C) 供应和利用之间的平衡才能持续生长，因为 C 饥饿通常会对作物生产造成不可逆转的损害。玉米等作物叶片中的碳固定和分配如何适应突然的环境变化尚不清楚。在这里，为了量化长时间黑暗下光合玉米叶片中的初级 C 固定和分配，并将这些因素与植物生长联系起来，在第 6 片叶子完全展开阶段 (V6) 连续三天对玉米幼苗进行延长黑暗 (ED)。ED 降低植物生长和叶绿素水平，但不降低净 CO ₂的速率交换。由于光同化物减少，在 ED 下成熟叶片中淀粉和总可溶性碳水化合物 (TSC) 的积累也减少。然而，成熟叶中保留的每日 C 固定百分比增加。这些瞬态 C 池主要由 TSC 组成，主要用于通过增加夜间呼吸而不是运输来消耗。随着时间的推移，累积的碳量和保留在叶片中的每日固定碳的百分比都在下降，这在很大程度上可以归因于所有处理中淀粉合成减弱。ADP-葡萄糖焦磷酸化酶和可溶性淀粉合酶的活性随时间显着降低。所以，该研究得出结论，淀粉和 TSC 都参与了 C 突然短缺下的 C 供应和植物生长的协调，但它们可能以不同的方式参与。虽然在急性 C 饥饿下保留 C 与每日固定 C 的比率增加以维持叶片功能，但随着植物继续生长以满足植物的生长需求，成熟叶片中保留的 C 量和比例均下降。