Department of Biology, Marmara University, Göztepe Campus, Kadıköy, 34722, Istanbul, Turkey.
Department of Life Sciences, University of Siena, Via Mattioli 4, 53100, Siena, Italy.
Plant Physiol Biochem. 2020 Nov;156:578-590. doi: 10.1016/j.plaphy.2020.10.008. Epub 2020 Oct 12.
The aim of the current study was to examine the effect of spermidine treatment concomitant with cold stress on the elongation of Camellia sinensis pollen tube. When exogenous spermidine (0.05 mM) was applied concomitantly with cold stress, pollen germination rate and pollen tube length were significantly increased in comparison with cold stressed pollen tubes. In addition, spermidine treatment concomitantly with cold stress reduced pollen tube abnormalities induced by cold stress. Besides, cold-induced disorganizations of actin filaments were ameliorated after spermidine treatment along with cold stress because anisotropy levels of actin filaments in shank and apex of pollen tubes decreased. Changes in cold-induced callose distribution in the pollen tube cell wall were partially recovered after spermidine/cold stress treatment. Other cold-induced effects (decrease in Ca content, reduction of pH gradient, accumulation of ROS) were reverted to adequate levels after spermidine treatment in conjunction with cold stress, indicating that pollen tubes are able to cope with stress. Thus, spermidine treatment reorganized the growth pattern of pollen tubes by modulating Ca and ROS homeostasis, actin cytoskeleton organization, and cell wall deposition in Camellia sinensis pollen tubes under cold stress.
本研究旨在探讨精胺处理与冷胁迫协同作用对茶树花粉管伸长的影响。当外源精胺（0.05 mM）与冷胁迫同时施加时，与冷胁迫花粉管相比，花粉萌发率和花粉管长度显著增加。此外，精胺处理与冷胁迫协同作用可减少冷胁迫引起的花粉管异常。此外，冷胁迫后花粉管中段和顶端的肌动蛋白丝各向异性水平降低，表明精胺处理协同冷胁迫可改善冷诱导的肌动蛋白丝解聚。精胺/冷胁迫处理后，花粉管细胞壁中冷诱导的胼胝质分布的变化部分得到恢复。其他冷诱导效应（Ca 含量降低、pH 梯度减小、ROS 积累）在冷胁迫下用精胺处理后恢复到适当水平，表明花粉管能够应对胁迫。因此，精胺处理通过调节 Ca 和 ROS 稳态、肌动蛋白细胞骨架组织和细胞壁沉积，重新组织了茶树花粉管在冷胁迫下的生长模式。
