Department of Civil and Architecture and Engineering, Chuzhou University, Anhui, China.
College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, China.
Plant Biol (Stuttg). 2023 Aug;25(5):696-702. doi: 10.1111/plb.13538. Epub 2023 Jun 6.
Water uptake is the fundamental and essential requirement for seed germination. Pecan seed has a hard woody endocarp that plays an important role during water uptake. To explore water uptake during germination, the spatiotemporal pattern of water and effect of the endocarp were analysed using high-field MRI, dye-tracing, wax blocking and SEM of water uptake. Isolated seeds completed water uptake in 8 h while whole seeds required 6 days, hence, cracking the endocarp plays an important role. The hilum is the channel through which water enters the seed, while the remainder of the seed coat consist of cells covered with a waxy layer that act as a barrier to water absorption. The region with the highest water content in pecan seed is the edge of the U-shaped region, and water can progressively diffuse from this U-shaped region into the whole kernel. We report a new water absorption stage between phase II and phase III of the triphasic model of water uptake of pecan seeds. Cracking the endocarp changed water distribution in pecan seeds, which may trigger further water absorption and radicle elongation.
吸水是种子萌发的基本和必要条件。山核桃种子有一个坚硬的木质内果皮，在吸水过程中起着重要作用。为了探索萌发过程中的吸水情况，使用高场 MRI、染料示踪、蜡封和 SEM 分析了吸水过程中的时空模式和内果皮的作用。分离的种子在 8 小时内完成吸水，而整个种子需要 6 天，因此，内果皮的开裂起着重要作用。种脐是水进入种子的通道，而种皮的其余部分由覆盖有蜡层的细胞组成，蜡层是吸水的障碍。山核桃种子含水量最高的区域是 U 形区域的边缘，水可以从这个 U 形区域逐渐扩散到整个内核。我们报告了山核桃种子吸水三阶段模型的第二阶段和第三阶段之间的一个新的吸水阶段。内果皮的开裂改变了山核桃种子中的水分分布，这可能会引发进一步的吸水和胚根伸长。
