An osmotic model of the growing pollen tube.
An osmotic model of the growing pollen tube.
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DOI：
10.1371/journal.pone.0036585
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Shachar-Hill Y
中科院分区：
文献类型：
--
作者：
Hill AE;Shachar-Hill B;Skepper JN;Powell J;Shachar-Hill Y
花粉管生长是植物有性繁殖的核心，也是细胞尖端生长的长期模型。为了使尖端快速生长，细胞壁沉积和硬化必须平衡渗透水的吸收速率，这涉及膨胀压力的控制。压力直接影响水进入的驱动力和导致壁材料变薄的尖端膨胀。了解尖端生长需要分析这些过程的协调及其调节。在这里，我们开发了一个定量生理模型，其中包括通过渗透作用进入水、细胞壁材料的掺入以及该材料在尖端作为薄膜的扩散。该模型的参数是根据文献和通过光、共焦和电子显微镜进行的测量以及长花百合的染料进入和质壁分离实验的结果确定的。该模型产生渗透压和膨胀压、生长速率和壁厚等变量值。通过将编程模拟与生长介质扰动后的实验观察结果进行比较来测试模型及其预测能力。该模型解释了膨胀压力的作用及其在振荡期间观察到的恒定性；不同条件下壁厚的稳定性，否则细胞会破裂；以及一些令人惊讶的特性，例如需要将渗透率限制在尖端附近的恒定区域，这一点已得到实验证实。为了在稳态生长中观察到的条件范围内实现压力和壁厚的恒定性，该模型揭示了需要一个传感器来检测水进入的驱动潜力并控制尖端壁材料的沉积速率。
Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip.
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DOI：
10.1083/jcb.144.3.483
发表时间：
1999-02-08
期刊：
The Journal of cell biology
影响因子：
--
作者：
Feijó JA;Sainhas J;Hackett GR;Kunkel JG;Hepler PK
通讯作者：
Hepler PK
影响因子：
9.2
作者：
Campas, Otger;Mahadevan, L.
通讯作者：
Mahadevan, L.
影响因子：
7.4
作者：
Dumais, J;Long, SR;Shaw, SL
通讯作者：
Shaw, SL
影响因子：
6.9
作者：
Cheung, Alice Y.;Wu, Hen-Ming
通讯作者：
Wu, Hen-Ming
影响因子：
11.4
作者：
Chen, Li-Qun;Ye, De
通讯作者：
Ye, De