Mineral Nutrition Lab # 108-109, Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
ICAR-Sugarcane Breeding Institute, Coimbatore, India.
Plant Cell Rep. 2018 Sep;37(9):1231-1244. doi: 10.1007/s00299-018-2307-4. Epub 2018 Jun 4.
Hexaploid wheat is more responsive than tetraploid to the interactive effects of elevated [CO] and low P in terms of carboxylate efflux, enzyme activity and gene expression (TaPT1 and TaPAP). Availability of mineral nutrients to plants under changing climate has become a serious challenge to food security and economic development. An understanding of how elevated [CO] influences phosphorus (P) acquisition processes at the whole-plant level would be critical in selecting cultivars as well as to maintain optimum yield in limited-P conditions. Wheat (Triticum aestivum and T. durum) grown hydroponically with sufficient and low P concentration were exposed to elevated and ambient [CO]. Improved dry matter partitioning towards root resulted in increased root-to-shoot ratio, root length, volume, surface area, root hair length and density at elevated [CO] with low P. Interaction of low P and [CO] induced activity of enzymes (phosphoenolpyruvate carboxylase, malate dehydrogenase and citrate synthase) in root tissue resulting in twofold increase in carboxylates and acid phosphatase exudation. Physiological absorption capacity of roots showed that plants alter their uptake kinetics by increasing affinity (low K) in response to elevated [CO] under low P supply. Increased relative expression of genes, purple acid phosphatase (TaPAP) and high-affinity Pi transporter (TaPT1) in roots induced by elevated [CO] and low P supported our physiological observations. Hexaploid wheat (PBW-396) being more responsive to elevated [CO] at low P supply as compared to tetraploid (PDW-233) necessitates the ploidy effect to be explored further which might be advantageous under changing climate.
六倍体小麦比四倍体小麦对[CO]升高和低磷的互作效应更为敏感，表现在羧酸外排、酶活性和基因表达（TaPT1 和 TaPAP）方面。在气候变化下，植物对矿质养分的利用成为粮食安全和经济发展的严重挑战。了解[CO]升高如何影响植物整体的磷获取过程，对于选择品种以及在有限磷条件下维持最佳产量至关重要。在水培条件下，用充足和低磷浓度培养小麦（Triticum aestivum 和 T. durum），然后将其暴露于升高和环境[CO]中。在低磷条件下，[CO]升高导致向根分配的干物质增加，从而增加了根冠比、根长、体积、表面积、根毛长度和密度。低磷和[CO]的相互作用诱导了根组织中酶（磷酸烯醇丙酮酸羧激酶、苹果酸脱氢酶和柠檬酸合酶）的活性，导致羧酸和酸性磷酸酶的分泌增加了两倍。根的生理吸收能力表明，植物通过增加亲和力（低 K）来改变其吸收动力学，以响应低磷供应下的[CO]升高。根中基因（紫色酸性磷酸酶（TaPAP）和高亲和力 Pi 转运蛋白（TaPT1））的相对表达增加，这支持了我们对生理观察的解释。与四倍体（PDW-233）相比，六倍体小麦（PBW-396）在低磷供应下对[CO]升高的响应更为敏感，这需要进一步探索多倍体效应，这在气候变化下可能是有利的。
