Li Li, Li Jinling, Wang Xiaoke, Wang Weifeng, Leung Felix, Liu Xiao, Wang Chao
Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; Bamboo Research Institute, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Bamboo Research Institute, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.
Sci Total Environ. 2022 Jun 20;826:154096. doi: 10.1016/j.scitotenv.2022.154096. Epub 2022 Feb 24.
Regional increases in atmospheric O, mainly produced photochemically from anthropogenic precursor gases, have phytotoxicity due to its strong oxidizing properties. To determine the response of bamboo physiology to elevated O levels, three-year-old dwarf bamboo (Indocalamus decorus) clones were exposed to three O concentrations (Ambient-AA, 21.3 to 80.9 ppb in the daytime; -AA+70, 70 ppb O above ambient; -AA+140, 140 ppb O above ambient) in open-top chambers for one growing season in Beijing, China. Gas exchange, biomass, growth, soluble sugar, and starch contents were examined at the end of the experiment. Our findings indicated that: (1) elevated O treatments decreased the photosynthesis rate, total biomass, and bud numbers but increased individual bud biomass and rhizome bud to rhizome biomass ratio. The most severe reduction was observed in new rhizome biomass (35.9% reduction in AA+70 and 57.2% reduction in AA+140), whereas individual bud biomass increased by 50% and 75% in the AA+70 and AA+140 groups compared with AA, respectively; (2) the starch contents in the rhizome decreased by 28.4%, whereas soluble sugar increased by 38.1% in the AA+140 rhizome buds compared to AA; (3) only the culm numbers of pachymorph rhizomes (clumped) decreased, whereas no changes in leptomorph rhizomes were observed. However, the mean distance between two ramets was lengthened by 49.4% and 86.5% in AA+70 and AA+140, respectively. In conclusion, Indocalamus decorus allocated more nonstructural carbohydrates (NSCs) from the rhizome to the buds to form stronger buds and ensure the survival of newer generations as a high priority in response to O exposure. Indocalamus decorus may be conducive to escaping from disadvantaged habitats and decreasing resource competition by lengthening the distance between two ramets.
大气中O的区域性增加主要由人为前驱气体通过光化学作用产生，因其具有强氧化性而具有植物毒性。为了确定竹子生理对升高的O水平的响应，在中国北京的开顶式气室中，将三年生的矮竹（美丽箬竹）克隆体暴露于三种O浓度下（环境浓度 - AA，白天为21.3至80.9 ppb；- AA + 70，比环境浓度高70 ppb O；- AA + 140，比环境浓度高140 ppb O），为期一个生长季节。在实验结束时检测了气体交换、生物量、生长、可溶性糖和淀粉含量。我们的研究结果表明：（1）升高的O处理降低了光合速率、总生物量和芽数，但增加了单个芽生物量以及根状茎芽与根状茎生物量的比率。新根状茎生物量的减少最为严重（AA + 70组减少35.9%，AA + 140组减少57.2%），而与AA组相比，AA + 70组和AA + 140组的单个芽生物量分别增加了50%和75%；（2）与AA组相比，AA + 140根状茎芽中的淀粉含量下降了28.4%，而可溶性糖增加了38.1%；（3）只有块状根状茎（丛生）的茎数减少，而细根状茎未观察到变化。然而，AA + 70组和AA + 140组中两个分株之间的平均距离分别延长了49.4%和86.5%。总之，美丽箬竹将更多的非结构性碳水化合物（NSCs）从根状茎分配到芽中，以形成更强壮的芽，并确保新一代的生存作为应对O暴露的首要任务。美丽箬竹可能有利于通过延长两个分株之间的距离逃离不利生境并减少资源竞争。
