We studied the maize leaf to understand how long-distance signals, auxin and cytokinin, control leaf growth dynamics. We constructed a mathematical model describing the transport of these hormones along the leaf growth zone and their interaction with the local gibberellin (GA) metabolism in the control of cell division. Assuming gradually declining auxin and cytokinin supply at the leaf base, the model generated spatiotemporal hormone distribution and growth patterns that matched experimental data. At the cellular level, the model predicted a basal leaf growth as a result of cell division driven by auxin and cytokinin. Superimposed on this, GA synthesis regulated growth through the control of the size of the region of active cell division. The predicted hormone and cell length distributions closely matched experimental data. To correctly predict the leaf growth profiles and final organ size of lines with reduced or elevated GA production, the model required a signal proportional to the size of the emerged part of the leaf that inhibited the basal leaf growth driven by auxin and cytokinin. Excision and shading of the emerged part of the growing leaf allowed us to demonstrate that this signal exists and depends on the perception of light intensity.

中文翻译：

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草如何保持生长：对玉米叶片生长区中的激素串扰的综合分析。

我们研究了玉米叶片，以了解长途信号，生长素和细胞分裂素如何控制叶片生长动态。我们构建了一个数学模型，描述了这些激素沿叶生长区的运输及其与局部赤霉素（GA）代谢在细胞分裂控制中的相互作用。假设叶基的生长素和细胞分裂素的供应逐渐下降，该模型产生的时空激素分布和生长模式与实验数据相符。在细胞水平上，该模型预测由于生长素和细胞分裂素驱动的细胞分裂，基础叶片的生长。在此基础上，GA合成通过控制活性细胞分裂区域的大小来调节生长。预测的激素和细胞长度分布紧密匹配实验数据。为了正确地预测GA产量降低或升高的品系叶片的生长曲线和最终器官的大小，该模型需要一个与叶片出苗部分的大小成比例的信号，该信号会抑制植物生长素和细胞分裂素驱动的基础叶片的生长。对生长中的叶片的出射部分进行切除和遮蔽使我们能够证明该信号存在并取决于对光强度的感知。