Tang Wei, Mo Qiong, Fu Yangyang, Zhang Damao, Liu Yang, Ren Mingtong, Li Tingting, Wu En, Su Dingding, Yu Xiaoying, Yan Lihong, Li Yanlin
Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding (Ministry of Education), Hunan Mid-Subtropical Quality Plant Breeding and Utilization Engineering Technology Research Center, Hunan Agricultural University, Changsha, China.
Institute of Advanced Agricultural Sciences, Peking University, Weifang, China.
PeerJ. 2025 Sep 10;13:e19855. doi: 10.7717/peerj.19855. eCollection 2025.
Drought stress is a predominant environmental challenge that significantly limits plant growth and survival, particularly affecting agricultural productivity and ecological stability in arid and semi-arid regions. This study aimed to elucidate the physiological responses of one-year-old Hemsl seedlings to various degrees of drought stress, thereby aiding their cultivation and application in challenging environments. To simulate real-world drought conditions, four levels of drought stress were defined based on soil moisture content: control (80% soil moisture), mild drought (LD, 50-60% soil moisture), moderate drought (MD, 40-50% soil moisture), and severe drought (SD, 20-30% soil moisture). These thresholds were selected to represent a gradient from optimal water availability to extreme water scarcity, reflecting conditions commonly encountered in drought-prone regions. The results revealed that drought stress profoundly inhibited growth, primarily affecting plant height and reducing the number and length of new shoots. Notably, leaves under moderate and SD conditions demonstrated significant wilting and subsequent death. Photosynthetic pigment content and photosynthesis-related parameters initially increased but subsequently experienced a sharp decline as drought stress persisted. Biochemical analyses indicated elevated levels of relative conductivity and malondialdehyde, indicating extensive cell membrane damage. In the meanwhile, the activities of key antioxidant enzymes (superoxide dismutase, peroxidase, and ascorbate peroxidase) increased, alongside higher accumulations of soluble sugars, soluble protein, and proline, albeit with a sluggish recovery observed under severe stress conditions. Anatomical studies highlighted the thickening of both the upper and lower epidermis, as well as a reduction in the density of palisade and spongy tissues. Recovery following rewatering was more effective under LD and MD conditions than under SD stress, indicating that possesses strong drought tolerance but is not suitable for highly arid regions. This study elucidates the adaptive mechanisms of under drought stress and provides practical guidance for its management and cultivation in drought-prone areas, enhancing its ecological and economic viability.
干旱胁迫是一个主要的环境挑战，它显著限制植物生长和存活，尤其影响干旱和半干旱地区的农业生产力和生态稳定性。本研究旨在阐明一年生天师粟幼苗对不同程度干旱胁迫的生理响应，从而有助于其在具有挑战性环境中的栽培和应用。为模拟实际干旱条件，根据土壤含水量定义了四个干旱胁迫水平：对照（土壤含水量80%）、轻度干旱（LD，土壤含水量50 - 60%）、中度干旱（MD，土壤含水量40 - 50%）和重度干旱（SD，土壤含水量20 - 30%）。选择这些阈值以代表从最佳水分可利用性到极端缺水的梯度，反映干旱易发地区常见的状况。结果表明，干旱胁迫严重抑制生长，主要影响株高并减少新梢数量和长度。值得注意的是，中度和重度干旱条件下的叶片出现显著萎蔫并随后死亡。光合色素含量和光合作用相关参数最初增加，但随着干旱胁迫持续随后急剧下降。生化分析表明相对电导率和丙二醛水平升高，表明细胞膜受到广泛损伤。与此同时，关键抗氧化酶（超氧化物歧化酶、过氧化物酶和抗坏血酸过氧化物酶）的活性增加，同时可溶性糖、可溶性蛋白和脯氨酸积累更高，尽管在重度胁迫条件下恢复缓慢。解剖学研究突出了上下表皮的增厚以及栅栏组织和海绵组织密度的降低。复水后，轻度和中度干旱条件下的恢复比重度干旱胁迫下更有效，表明天师粟具有较强的耐旱性，但不适合高度干旱地区。本研究阐明了天师粟在干旱胁迫下的适应机制，并为其在干旱易发地区的管理和栽培提供了实际指导，提高了其生态和经济可行性。
