Morphogenesis of complex plant cell shapes: the mechanical role of crystalline cellulose in growing pollen tubes
Morphogenesis of complex plant cell shapes: the mechanical role of crystalline cellulose in growing pollen tubes
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DOI：
10.1007/s00497-009-0110-7
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发表时间：
2010-03-01
影响因子：
--
通讯作者：
Geitmann, Anja
中科院分区：
文献类型：
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作者：
Aouar, Leila;Chebli, Youssef;Geitmann, Anja
纤维素是初生植物细胞壁中承载系统的主要成分。这种多糖对张力的巨大抵抗力及其嵌入基质成分使细胞壁成为一种类似于纤维复合材料的材料。在快速生长的花粉管中，细胞壁中的纤维素含量异常低。因此，我们想要研究纤维素的承载功能是否仍然对这个细胞的结构很重要。在茄子和东方百合萌发过程中，纤维素酶消化和CGA-(1-cyclohexyl-5-(2，3，4，5，6-pentafluorophenoxy)-1(4，2，4，6-噻三嗪-3-胺)抑制纤维素晶体的形成可导致管径增大。在萌发前的管子中，两种药物的应用都导致生长暂时停止，并伴随着顶端肿胀的形成，这表明在这一细胞区的机械稳定中发挥了作用。然而，一旦在纤维素酶存在下恢复生长，新形成的试管中的细胞壁显示出更多的果胶，可能是为了补偿减少的纤维素量。经基质多糖消化的花粉管的扫描电子显微镜显示了细胞壁的机械各向异性。在百合和茄子中，裂纹形成的最大稳定角都显著低于45A度，这表明在细胞的成熟部分，纤维可能不是抵抗膨胀压力引起的周向拉应力的主要应力成分。
Cellulose is the principal component of the load-bearing system in primary plant cell walls. The great resistance to tensile forces of this polysaccharide and its embedding in matrix components make the cell wall a material similar to a fiber composite. In the rapidly growing pollen tube, the amount of cellulose in the cell wall is untypically low. Therefore, we want to investigate whether the load-bearing function of cellulose is nevertheless important for the architecture of this cell. Enzymatic digestion with cellulase and inhibition of cellulose crystal formation with CGA (1-cyclohexyl-5-(2,3,4,5,6-pentafluorophenoxy)-1 lambda 4,2,4,6-thiatriazin-3-amine) resulted in the formation of tubes with increased diameter in Solanum chacoense and Lilium orientalis when present during germination. In pre-germinated tubes, application of both agents resulted in the transient arrest of growth accompanied by the formation of an apical swelling indicating a role in the mechanical stabilization of this cellular region. Once growth resumed in the presence of cellulase, however, the cell wall in the newly formed tube showed increased amounts of pectins, possibly to compensate for the reduced amount of cellulose. Scanning electron microscopy of pollen tubes subjected to digestion of matrix polysaccharides revealed the mechanical anisotropy of the cell wall. In both Lilium and Solanum, the angle of highest stability revealed by crack formation was significantly below 45A degrees, an indication that in the mature part of the cell cellulose may not the main stress-bearing component against turgor pressure induced tensile stress in circumferential direction.