Liu Xin, Wang Ping, An Yongping, Wang Chun-Mei, Hao Yanbo, Zhou Yue, Zhou Qingping, Wang Pei
Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu, China.
National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
Front Plant Sci. 2022 Sep 23;13:1007494. doi: 10.3389/fpls.2022.1007494. eCollection 2022.
Drought is the most serious adversity faced by agriculture and animal husbandry industries. One strategy that plants use to adapt to water deficits is modifying the root growth and architecture. Root endodermis has cell walls reinforced with apoplastic barriers formed by the Casparian strip (CS) and suberin lamellae (SL) deposits, regulates radial nutrient transport and protects the vascular cylinder from abiotic threats. is an economically important meso-xerophytic forage grass, characterized by high nutritional quality and strong environmental adaptability. The purpose of this study was to evaluate the drought tolerance of genotypes and investigate the root structural adaptation mechanism of drought-tolerant genotypes' responding to drought. Specifically, a drought tolerant (DT) and drought sensitive (DS) genotype were screened out from 52 genotypes. DT showed less apoplastic bypass flow of water and solutes than DS under control conditions, as determined with a hydraulic conductivity measurement system and an apoplastic fluorescent tracer, specifically PTS trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS). In addition, DT accumulated less Na, Mg, Mn, and Zn and more Ni, Cu, and Al than DS, regardless of osmotic stress. Further study showed more suberin deposition in DT than in DS, which could be induced by osmotic stress in both. Accordingly, the CS and SL were deposited closer to the root tip in DT than in DS. However, osmotic stress induced their deposition closer to the root tips in DS, while likely increasing the thickness of the CS and SL in DT. The stronger and earlier formation of endodermal barriers may determine the radial transport pathways of water and solutes, and contribute to balance growth and drought response in . These results could help us better understand how altered endodermal apoplastic barriers in roots regulate water and mineral nutrient transport in plants that have adapted to drought environments. Moreover, the current findings will aid in improving future breeding programs to develop drought-tolerant grass or crop cultivars.
干旱是农牧业面临的最严重逆境。植物适应水分亏缺的一种策略是改变根系生长和结构。根内皮层具有由凯氏带（CS）和栓质化层（SL）沉积物形成的质外体屏障加强的细胞壁，调节径向养分运输并保护维管束免受非生物胁迫。[植物名称]是一种具有重要经济价值的中生旱生饲草，具有高营养品质和强环境适应性。本研究的目的是评估[植物名称]基因型的耐旱性，并研究耐旱基因型对干旱响应的根系结构适应机制。具体而言，从52个[植物名称]基因型中筛选出一个耐旱（DT）和一个干旱敏感（DS）基因型。在对照条件下，通过水力传导率测量系统和质外体荧光示踪剂，特别是PTS三钠-8-羟基-1,3,6-芘三磺酸（PTS）测定，DT显示的水分和溶质的质外体旁路流量比DS少。此外，无论渗透胁迫如何，DT积累的钠、镁、锰和锌比DS少，而镍、铜和铝比DS多。进一步研究表明，DT中的栓质沉积比DS多，二者均可由渗透胁迫诱导。因此，DT中CS和SL比DS更靠近根尖沉积。然而，渗透胁迫在DS中诱导它们更靠近根尖沉积，而可能增加DT中CS和SL的厚度。内皮层屏障更强和更早的形成可能决定水分和溶质的径向运输途径，并有助于[植物名称]的生长和干旱响应平衡。这些结果可以帮助我们更好地理解根系中内皮层质外体屏障的改变如何调节适应干旱环境的植物中的水分和矿质养分运输。此外，目前的研究结果将有助于改进未来的育种计划，以培育耐旱牧草或作物品种。
