Guo Pingping, Zhao Xiping, Yang Zifei, Wang Yingxin, Li Hongying, Zhang Lepei
College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, 471023, China.
Heliyon. 2024 Feb 27;10(5):e27231. doi: 10.1016/j.heliyon.2024.e27231. eCollection 2024 Mar 15.
'Jinsi', a cultivar of C. A. Mey., is valued for its heartwood with good overall mechanical properties, naturally durable and golden-yellow color. Little is known about heartwood formation in 'Jinsi' trees. The behavior of starch, water, and nuclei was studied in the xylem tissue of 'Jinsi' concerning aging in ray parenchyma cells. Blocks containing heartwood, golden zone, transition zone, and sapwood were collected from the stems of six 'Jinsi' trees. The moisture content of the blocks was measured by oven drying. Changes in starch and nuclei in ray parenchyma were investigated in radial profiles from sapwood to heartwood blocks using microscopy and various staining techniques. The nuclear size and starch content gradually decreased to heartwood. While the horizontal distribution of moisture content of 'Jinsi' was very varied, with the heartwood and golden zone being lower than sapwood but slightly higher than the transition zone. Starch grains were rare, but nuclei were still present in some ray parenchyma cells in the heartwood and golden zone. The nuclei showed irregular shape and elongation before disintegration. These results suggest that the most apparent change occurs in the transition zone, the critical location involved in forming 'Jinsi' heartwood. Water and starch appear to be actively engaged in heartwood formation. The loss of function of ray parenchyma cells results from heartwood formation.
“金丝”是锦鸡儿属的一个栽培品种，因其心材具有良好的综合机械性能、天然耐久性和金黄色而备受重视。关于“金丝”树的心材形成知之甚少。研究了“金丝”木质部组织中淀粉、水分和细胞核在射线薄壁细胞衰老过程中的行为。从六棵“金丝”树的茎干中采集了包含心材、金色区域、过渡区域和边材的木块。通过烘干法测量木块的含水量。利用显微镜和各种染色技术，研究了从边材到心材木块的径向剖面中射线薄壁细胞中淀粉和细胞核的变化。细胞核大小和淀粉含量向心材方向逐渐降低。虽然“金丝”含水量的水平分布差异很大，心材和金色区域低于边材，但略高于过渡区域。淀粉粒很少见，但在心材和金色区域的一些射线薄壁细胞中仍存在细胞核。细胞核在解体前呈现不规则形状并伸长。这些结果表明，最明显的变化发生在过渡区域，这是形成“金丝”心材的关键位置。水分和淀粉似乎积极参与心材形成。射线薄壁细胞功能的丧失是心材形成导致的。
