Liu Yuanxi, Sun Jianli, Dai Cefeng, Du Guanben, Shi Rui, Wu Junwen
College of Forestry, Southwest Forestry University, Kunming 650224, China.
College of Materials and Chemical Engineering, Southwest Forestry University, Kunming 650224, China.
Plants (Basel). 2025 May 27;14(11):1636. doi: 10.3390/plants14111636.
Swartz is a rapidly growing plant known for its lightweight wood; it is widely utilized for timber production and ecological restoration. We investigated the effects of different numbers of drought-rehydration cycles on seedlings cultivated at the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences. The experiment comprised three treatments: normal watering (CK, 80-85% field capacity), one drought-rehydration cycle (D1, one rewatering), and three drought-rehydration cycles (D2, three rewaterings). We characterized the effects of these treatments on seedling growth, biomass allocation, non-structural carbohydrates (NSCs), malondialdehyde (MDA), catalase (CAT) activity, peroxidase (POD) activity, superoxide dismutase (SOD) activity, proline content, and soluble protein content. The number of drought-rehydration cycles had a significant effect on the growth characteristics and physiological and biochemical properties of leaves. As the number of drought-rehydration cycles increased, the height increased significantly (by 17.17% under D2). The leaf biomass ratio, soluble sugar content, and starch content decreased (15.05%, 15.79%, and 46.92% reductions under the D2 treatment); the stem biomass ratio and root biomass ratio increased; CAT activity increased and then decreased (it was highest at 343.67 mg·g·min under D1); and the POD and SOD activities, the MDA content, the soluble protein content, and the soluble sugar/starch ratio increased significantly (395.42%, 461.82%, 74.72%, 191.07%, and 59.79% higher under D2). The plasticity of growth was much greater than that of physiological and biochemical traits. In summary, seedlings adapted to multiple drought-rehydration cycles by increasing the accumulation of soluble proteins (likely associated with osmotic protection), activating enzymes (POD and SOD), promoting the conversion of NSCs (increasing stored carbon consumption), and allocating more biomass to plant height growth than to diameter expansion. Under climate change scenarios with intensified drought frequency, elucidating the drought resistance mechanisms of is critical to silvicultural practices in tropical plantation.
斯沃茨（Swartz）是一种生长迅速的植物，以其轻质木材而闻名；它被广泛用于木材生产和生态恢复。我们在中国科学院西双版纳热带植物园对不同干旱-复水循环次数对幼苗的影响进行了研究。该实验包括三种处理：正常浇水（CK，田间持水量的80-85%）、一次干旱-复水循环（D1，一次再浇水）和三次干旱-复水循环（D2，三次再浇水）。我们对这些处理对幼苗生长、生物量分配、非结构性碳水化合物（NSCs）、丙二醛（MDA）、过氧化氢酶（CAT）活性、过氧化物酶（POD）活性、超氧化物歧化酶（SOD）活性、脯氨酸含量和可溶性蛋白含量的影响进行了表征。干旱-复水循环次数对叶片的生长特性以及生理和生化特性有显著影响。随着干旱-复水循环次数的增加，株高显著增加（D2处理下增加了17.17%）。叶片生物量比、可溶性糖含量和淀粉含量下降（D2处理下分别降低了15.05%、15.79%和46.92%）；茎生物量比和根生物量比增加；CAT活性先增加后降低（D1处理下最高为343.67毫克·克·分钟）；POD和SOD活性、MDA含量、可溶性蛋白含量以及可溶性糖/淀粉比显著增加（D2处理下分别高出395.42%、461.82%、74.72%、191.07%和59.79%）。生长的可塑性远大于生理和生化性状的可塑性。总之，幼苗通过增加可溶性蛋白的积累（可能与渗透保护有关）、激活酶（POD和SOD）、促进NSCs的转化（增加储存碳的消耗）以及将更多生物量分配到株高生长而非直径扩展来适应多次干旱-复水循环。在干旱频率加剧的气候变化情景下，阐明斯沃茨的抗旱机制对于热带人工林的造林实践至关重要。
