Cosgrove D J
Department of Biology, Pennsylvania State University, University Park 16802, USA.
Nature. 2000 Sep 21;407(6802):321-6. doi: 10.1038/35030000.
Plant cell walls are the starting materials for many commercial products, from lumber, paper and textiles to thickeners, films and explosives. The cell wall is secreted by each cell in the plant body, forming a thin fibreglass-like network with remarkable strength and flexibility. During growth, plant cells secrete a protein called expansin, which unlocks the network of wall polysaccharides, permitting turgor-driven cell enlargement. Germinating grass pollen also secretes an unusual expansin that loosens maternal cell walls to aid penetration of the stigma by the pollen tube. Expansin's action has puzzling implications for plant cell-wall structure. The recent explosion of gene sequences and expression data has given new hints of additional biological functions for expansins.
植物细胞壁是许多商业产品的原材料，从木材、纸张和纺织品到增稠剂、薄膜和炸药。细胞壁由植物体内的每个细胞分泌形成，是一个具有非凡强度和柔韧性的类似玻璃纤维的薄网络。在生长过程中，植物细胞分泌一种叫做膨胀素的蛋白质，它解开细胞壁多糖网络，使膨压驱动的细胞扩张成为可能。发芽的禾本科花粉也会分泌一种特殊的膨胀素，这种膨胀素会使母本细胞壁松弛，以帮助花粉管穿透柱头。膨胀素的作用对植物细胞壁结构有着令人困惑的影响。最近基因序列和表达数据的激增为膨胀素的其他生物学功能提供了新的线索。
