School of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
National Engineering Research Center for Floriculture, Beijing, 100083, China.
Planta. 2024 Sep 15;260(4):96. doi: 10.1007/s00425-024-04530-y.
Four cultivars of Paeonia lactiflora pollen have a different viability after cryopreservation, and that the difference of pollen viability is related to calcium ions and cell wall deposition. Cryopreservation is a vital technique for preserving germplasm resources, offering extensive application prospects. Understanding the factors influencing pollen viability after cryopreservation is crucial for the permanent preservation and exchange of pollen resources. This study investigated pollen from four Paeonia lactiflora cultivars with varying viability after cryopreservation, aiming to determine whether calcium ions (Ca) and cell wall deposition affect these viability changes. The results showed that Ca-ATPase activity and cytoplasmic Ca of all four cultivars exhibited an increasing trend after cryopreservation; the calmodulin (CaM) content varied with cultivars. Correlation analysis showed that fresh pollen viability was significantly negatively correlated with cytoplasmic Ca content and positively correlated with Ca-ATPase activity, while pollen viability after cryopreservation exhibited a significantly negative correlation with cytoplasmic Ca content and a positive correlation with CaM content. The pollen cell wall of the cultivar 'Zi Feng Chao Yang' (ZFCY), which showed increased viability after cryopreservation, contained significantly higher levels of low-temperature tolerance-related phospholipids and proteins compared to other cultivars. Additionally, all cultivars maintained a clear Ca gradient at the tips of pollen tubes after cryopreservation, without significant callose accumulation. These findings suggest that differences in Ca signaling and cell wall components deposition influence changes in pollen viability after cryopreservation, and the Ca gradient and callose at the tip of pollen tubes are not responsible for preventing pollen tube growth.
四种芍药花粉在经过冷冻保存后具有不同的活力，而花粉活力的差异与钙离子和细胞壁沉积有关。冷冻保存是保存种质资源的重要技术，具有广泛的应用前景。了解冷冻保存后花粉活力的影响因素对于花粉资源的永久保存和交流至关重要。本研究调查了四种经过冷冻保存后活力不同的芍药花粉，旨在确定钙离子（Ca）和细胞壁沉积是否影响这些活力变化。结果表明，四种芍药花粉在经过冷冻保存后，Ca-ATP 酶活性和细胞质 Ca 均呈现上升趋势；钙调素（CaM）含量因品种而异。相关分析表明，新鲜花粉活力与细胞质 Ca 含量呈显著负相关，与 Ca-ATP 酶活性呈显著正相关，而冷冻保存后花粉活力与细胞质 Ca 含量呈显著负相关，与 CaM 含量呈显著正相关。经过冷冻保存后活力增加的品种‘紫凤朝阳’（ZFCY）花粉细胞壁含有更高水平的与低温耐受性相关的磷脂和蛋白质。此外，所有品种在经过冷冻保存后花粉管尖端都保持着明显的 Ca 梯度，没有明显的胼胝质积累。这些发现表明，Ca 信号和细胞壁成分沉积的差异影响冷冻保存后花粉活力的变化，花粉管尖端的 Ca 梯度和胼胝质不是防止花粉管生长的原因。
