College of Forestry, Jiangxi Agricultural University, Nanchang, Jiangxi, China.
Jiangxi Provincial Key Laboratory for Bamboo Germplasm Resources and Utilization, Nanchang, Jiangxi, China.
PLoS One. 2020 Dec 11;15(12):e0241806. doi: 10.1371/journal.pone.0241806. eCollection 2020.
In this study, we investigated the changes in the distribution and regulation of endogenous hormones in Phyllostachys edulis 'Pachyloen' during bamboo shooting. Enzyme-linked immunosorbent assay was used to measure the mass fractions of indole-3-acetic acid (IAA), gibberellic acid (GA), zeatin riboside (ZR), and abscisic acid (ABA) in rhizomes, shoots, and maternal bamboo organs during shoot sprouting, shoot growth, and new-bamboo formation. Measurements were compared among bamboo parts and developmental periods. The overall mass fractions of IAA and ABA were significantly higher than those of ZR and GA, driven by differences among bamboo parts and developmental periods. The abundance of each endogenous hormone varied among bamboo parts and developmental periods. During bamboo shooting, ABA had the highest mass fraction in all bamboo parts sampled, followed by IAA, GA, and ZR. Among bamboo parts, rhizomes had more IAA, ZR, and GA than the other parts, but significantly less ABA. Winter shoots had higher ZR: IAA and GA: IAA ratios than rhizomes and maternal bamboo organs. During shoot growth, ABA was the most abundant hormone in rhizomes and maternal bamboo organs, followed by IAA, ZR, and GA. In contrast, IAA was the most abundant hormone in spring shoots, followed by ABA, ZR, and GA. Maternal bamboo organs had a significantly higher ZR: GA ratio, and significantly lower IAA: ABA, ZR: ABA, and GA: ABA ratios than rhizomes. Spring shoots had significantly higher IAA: ABA, ZR: ABA, and GA: ABA ratios than rhizomes and maternal bamboo organs; significantly higher ZR mass fractions, and ZR: GA and ZR: IAA ratios and significantly lower ABA mass fractions than rhizomes; and significantly higher GA: IAA ratio than maternal bamboo organs. During new-bamboo formation, ABA was the most abundant hormone in rhizomes, winter shoots, and maternal bamboo organs, followed by IAA, ZR, and GA. Maternal bamboo organs had significantly lower IAA mass fractions and significantly higher ABA mass fractions than rhizomes and new bamboo tissue. IAA and ABA abundances exhibited an inverse relationship in rhizomes and maternal bamboo organs. GA: ABA and GA: IAA ratios decreased gradually and other hormone ratios exhibited parabolic trends over the bamboo-shooting period, with the highest ratios observed in new bamboo tissues. Overall, the coordination or antagonism among endogenous hormones plays a key regulatory role in bamboo shoot growth. The formation of thick walls in P. edulis 'Pachyloen', one of its major traits, may be partially attributed to the relatively high IAA and ZR and low GA mass fractions.
在这项研究中，我们调查了毛竹笋期内源激素在茎和母竹器官中的分布和调节变化。采用酶联免疫吸附法（ELISA）测定笋芽、竹笋和母竹器官中吲哚-3-乙酸（IAA）、赤霉素（GA）、玉米素核苷（ZR）和脱落酸（ABA）的质量分数。比较了竹笋生长过程中竹部分和发育阶段的质量分数。IAA 和 ABA 的总体质量分数明显高于 ZR 和 GA，这是由竹部分和发育阶段的差异引起的。每种内源激素的丰度在竹部分和发育阶段之间存在差异。在竹笋生长过程中，所有取样的竹部分中 ABA 的质量分数最高，其次是 IAA、GA 和 ZR。在竹部分中，根茎比其他部分含有更多的 IAA、ZR 和 GA，但 ABA 含量明显较低。冬季竹笋的 ZR：IAA 和 GA：IAA 比值高于根茎和母竹器官。在竹笋生长过程中，根茎和母竹器官中 ABA 的含量最高，其次是 IAA、ZR 和 GA。相比之下，春竹笋中 IAA 的含量最高，其次是 ABA、ZR 和 GA。与根茎相比，母竹器官中 ZR：GA 比值显著较高，IAA：ABA、ZR：ABA 和 GA：ABA 比值显著较低。春竹笋的 IAA：ABA、ZR：ABA 和 GA：ABA 比值显著高于根茎和母竹器官；ZR 质量分数显著较高，ZR：GA 和 ZR：IAA 比值显著较低，ABA 质量分数显著较低；GA：IAA 比值显著高于母竹器官。在新竹形成过程中，根茎、冬季竹笋和母竹器官中 ABA 的含量最高，其次是 IAA、ZR 和 GA。与根茎和新竹组织相比，母竹器官中的 IAA 质量分数显著较低，ABA 质量分数显著较高。根茎和母竹器官中 IAA 和 ABA 的丰度呈负相关。随着竹笋生长过程中 ABA：GA 和 ABA：IAA 比值逐渐降低，其他激素比值呈抛物线趋势，新竹组织中比值最高。总体而言，内源激素的协调或拮抗作用对内源激素在竹笋生长中的调节作用至关重要。毛竹“厚壁”的形成是其主要特征之一，这可能部分归因于较高的 IAA 和 ZR 以及较低的 GA 质量分数。
