二氧化碳浓度升高条件下生物量增加归因于干旱胁迫下桑树的生理优化、养分分配权衡及氧化防御。

Greater Biomass Production Under Elevated CO Is Attributed to Physiological Optimality, Trade-Offs in Nutrient Allocation, and Oxidative Defense in Drought-Stressed Mulberry.

作者信息

Shi Songmei, Li Huakang, Wang Xinju, Wang Ziran, Xu Junqiang, He Xinhua, Yang Zheng'an

机构信息

Key Laboratory of Vegetable Biology in Yunnan, College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China.

Centre of Excellence for Soil Biology, College of Resources and Environment, Southwest University, Chongqing 400716, China.

出版信息

Antioxidants (Basel). 2025 Mar 25;14(4):383. doi: 10.3390/antiox14040383.

DOI:10.3390/antiox14040383

PMID:40298623

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC12024246/

Abstract

Mulberry ( L.), a species of significant ecological and economic importance, is widely cultivated for sericulture, soil conservation, and environmental restoration. Despite its remarkable resilience to environmental stresses, the combined impact of elevated CO (eCO) and drought stress on aboveground-root-soil interactions remains poorly understood, particularly in the context of global climate change. Here, we investigated the effects of eCO and drought on physiological leaf and root indicators, nutrient absorption and allocation, and soil properties in mulberry seedlings. Mulberry seedlings were grown in environmentally auto-controlled growth chambers under ambient CO (420/470 ppm, day/night) or eCO (710/760 ppm) and well-watered (75-85% soil relative water content, RWC), moderate-drought (55-65% RWC), or severe-drought (35-45% RWC) conditions. Results showed that both above- and below-ground plant biomass production were significantly promoted by eCO, particularly by 36% and 15% under severe drought, respectively. This could be attributed to several factors. Firstly, eCO improved leaf photosynthesis by 25-37% and water use efficiency by 104-163% under drought stresses while reducing negative effects of drought on the effective quantum yield of PSII photochemistry and the photochemical quenching coefficient. Secondly, eCO significantly decreased proline accumulation while increasing soluble sugar contents, as well as peroxidase and superoxide dismutase activities, in both leaves and roots under drought stress. Lastly, eCO promoted soil sucrase, urease, and phosphatase activities, as well as plant nitrogen, phosphorus and potassium uptake while facilitating their allocation into roots under drought stress. These findings demonstrate that eCO enhanced the drought tolerance of mulberry plants through improvements in photosystem II efficiency, water use efficiency, antioxidative defense capacity, and nutrient uptake and allocation, providing critical insights for sustainable mulberry plantation management under future climate change scenarios.

摘要

桑（桑属）是一种具有重要生态和经济意义的物种，因其在养蚕、土壤保持和环境恢复方面的作用而被广泛种植。尽管桑树对环境胁迫具有显著的适应能力，但在全球气候变化的背景下，高浓度二氧化碳（eCO）和干旱胁迫对地上部-根系-土壤相互作用的综合影响仍知之甚少。在此，我们研究了eCO和干旱对桑树苗生理叶片和根系指标、养分吸收与分配以及土壤性质的影响。桑树苗在环境自动控制的生长室中培养，设置为大气CO₂浓度（420/470 ppm，白天/夜晚）或eCO₂浓度（710/760 ppm），并设置充分浇水（土壤相对含水量75 - 85%，RWC）、中度干旱（55 - 65% RWC）或重度干旱（35 - 45% RWC）条件。结果表明，eCO显著促进了地上部和地下部植物生物量的积累，在重度干旱条件下分别尤其提高了36%和15%。这可归因于几个因素。首先，在干旱胁迫下，eCO使叶片光合作用提高了25 - 37%，水分利用效率提高了104 - 163%，同时减少了干旱对PSII光化学有效量子产率和光化学猝灭系数的负面影响。其次，在干旱胁迫下，eCO显著降低了叶片和根系中脯氨酸的积累，同时增加了可溶性糖含量以及过氧化物酶和超氧化物歧化酶的活性。最后，在干旱胁迫下，eCO促进了土壤蔗糖酶、脲酶和磷酸酶的活性，以及植物对氮、磷和钾的吸收，同时促进了这些养分向根系的分配。这些发现表明，eCO通过提高光系统II效率、水分利用效率、抗氧化防御能力以及养分吸收与分配，增强了桑树的耐旱性，为未来气候变化情景下桑园的可持续管理提供了关键见解。