Sun Yan, Zhang Jinting, Li Weiwei, Xu Zikai, Wang Siji, Zhao Manli, Shen Jianbo, Cheng Lingyun
College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, State Key Laboratory of Nutrient Use and Management (SKL-NUM), Ministry of Education, China Agricultural University, Beijing 100193, P. R. China.
Ann Bot. 2024 Sep 18. doi: 10.1093/aob/mcae169.
Understanding how maize roots proliferate in phosphorus (P)-rich soil patches is critical for improving nutrient acquisition and crop productivity. This study explores the mechanisms of root adaptation to heterogeneous P availability, focusing on sucrose metabolism and the role of local P signals.
A split-root system with chambers of differing Pi concentrations (0 and 500 μM) was used to examine maize root responses. Various physiological and biochemical parameters, including root growth, sucrose partitioning, enzyme activities, and gene expression, were measured to elucidate the underlying mechanisms.
Root proliferation, particularly of second-order lateral roots, was markedly enhanced in P-rich patches. Sucrose was preferentially allocated to the Pi-supplied side, as confirmed by Fourier-transform infrared (FTIR) microscopy. Sucrose content in these roots decreased, indicating active metabolism. Higher activities of cell-wall invertase and sucrose synthase were observed in the Pi-supplied roots, supporting enhanced carbohydrate utilization.
Local P availability triggers significant adjustments in sucrose metabolism and allocation, enhancing the sink capacity of maize roots in P-rich patches. These changes facilitate efficient lateral root proliferation and Pi utilization, highlighting the critical role of local P signals in nutrient acquisition strategies. This research provides deeper insights into the adaptive responses of maize to heterogeneous P environments, offering potential strategies for improving crop nutrient efficiency.
了解玉米根系如何在富磷土壤斑块中增殖对于提高养分获取和作物生产力至关重要。本研究探讨根系适应磷有效性异质性的机制，重点关注蔗糖代谢和局部磷信号的作用。
采用具有不同磷浓度（0和500 μM）隔室的分根系统来研究玉米根系的反应。测量了包括根系生长、蔗糖分配、酶活性和基因表达在内的各种生理生化参数，以阐明潜在机制。
在富磷斑块中，根系增殖，尤其是二级侧根的增殖显著增强。傅里叶变换红外（FTIR）显微镜证实，蔗糖优先分配到供应磷的一侧。这些根系中的蔗糖含量下降，表明代谢活跃。在供应磷的根系中观察到细胞壁转化酶和蔗糖合酶的活性较高，支持了碳水化合物利用的增强。
局部磷有效性引发蔗糖代谢和分配的显著调整，增强了玉米根系在富磷斑块中的库容量。这些变化促进了侧根的有效增殖和磷的利用，突出了局部磷信号在养分获取策略中的关键作用。本研究为玉米对异质磷环境的适应性反应提供了更深入见解，为提高作物养分效率提供了潜在策略。
