淹水环境下河竹鞭根养分吸收与积累的适应性调节

为揭示河竹的耐水湿机制,为河竹在水湿地和江河湖库消落带植被恢复中应用提供理论依据,以河竹盆栽苗为试材,测定了淹水和人工喷灌供水处理3、6、12个月的河竹一年生竹鞭的根系生物量和主要养分元素含量,分析了河竹鞭根养分含量、化学计量比和养分积累量在淹水环境下的动态变化规律。结果表明:淹水3个月使河竹鞭根N、P、K含量显著降低,但对C、Ca、Fe、Mg等养分含量和C/P、N/P、N/K影响不明显,随着淹水时间的进一步延长,河竹鞭根养分含量、化学计量比和积累量发生明显变化,C、N、P、Ca含量和C/K、N/K、P/K降低,K、Fe、Mg含量和C/N、C/P、N/P升高;淹水6个月前对河竹鞭根养分积累总体上有明显抑制作用,但淹水12个月会使鞭根养分积累量显著升高,这主要源于根系生物量显著提高的贡献。研究表明,淹水3个月时,维持较高的养分内稳性是河竹应对胁迫环境的响应策略,随后通过土中根和水中根的大量生长来维持较高的养分吸收和积累能力,并进行养分化学计量比的适应性调节来适应胁迫环境。分析认为,河竹在长期淹水环境中能够维持生存,可以用于水湿地和江河湖库消落带植被恢复,也是净化富营养水体研究与应用的竹子材料。

Adaptive adjustment to nutrient absorption and accumulation of Phyllostachys rivalis rhizome-roots under waterlogged conditions

This study aimed to reveal the fluid resistance mechanism of Phyllostachys rivalis (Phyllostachys rivalis), a bamboo species, and provide a theoretical basis for its application in vegetation restoration of wetlands and areas with fluctuating water tables. We investigated the biomass and contents of the main nutrient elements in annual Phyllostachys rivalis rhizome-roots by using individually potted Phyllostachys rivalis with artificial irrigation for water supply and waterlogging in the third, sixth, and twelfth months. The nutrient contents, stoichiometric ratio, and nutrient accumulation were analyzed, and the following results were obtained: the contents of N, P, and K in Phyllostachys rivalis rhizome-roots decreased significantly under waterlogging in the third month. However, no obvious impact was noted on the contents of C, Ca, Fe, and Mg and C/P, N/P, and N/K. The nutrient contents, stoichiometric ratio, and nutrient accumulation altered markedly with prolonged waterlogging. Meanwhile, the contents of C, N, P, and Ca and C/K, N/K, and P/K decreased, and the contents of K, Fe, and Mg and C/N, C/P, and N/P increased with prolonged waterlogging. The accumulation of nutrients was significantly inhibited before waterlogging in the sixth month. However, the accumulation of nutrients showed a significant increase under waterlogging in the twelfth month; this was mainly because of significant increase in the root biomass. Thus, we showed that maintaining strong nutrition stability is a strategy of Phyllostachys rivalis in response to environmental stress. The rhizome-roots of Phyllostachys rivalis can sustain high nutrient absorption and accumulation through producing large numbers of roots, both in soil and water, and show adaptive regulation of the nutrient stoichiometric ratio in response to environmental stress. Since Phyllostachys rivalis can survive in long-term waterlogged environments, it could be used for vegetation restoration of wetlands and areas with fluctuating water tables. In addition, it may play an important role as one of the bamboo species that can be used for purifying eutrophic water bodies.