Morphological, Physiological, and Biochemical Composition of Mulberry (Morus spp.) under Drought Stress

Drought is the most important environmental factor inhibiting plant photosynthesis. In this study, the morphological characteristics, biomass allocation, and physiological and biochemical characteristics of four potted mulberry plants under drought stress were analyzed. The study revealed the drought tolerance differences of four mulberry potted seedlings in semi-arid sandy areas of China. Combined with the results of two-way ANOVA, under normal growth conditions, Shensang No. 1 and Ji’an grew well and produced higher benefits, which was attributed to their larger leaf areas, biomass, and total Chl contents, and there were significant differences between their other traits (p < 0.05). Drought stress led to a decrease in the photosynthetic capacity of the mulberry leaves, and the drought resistance capabilities of the four mulberry trees were different. Among the trees, Aerxiang and Fujia were less affected by drought, and their cultivation in a naturally arid environment was able to achieve certain drought resistance effects. The branch length, total leaf area, and specific leaf area were significantly differently correlated with the biomass components’ dry leaf weight, dry branch weight, dry root weight, total biomass, and root-to-crown ratio (p < 0.05), and there was also a significant positive correlation with the photosynthetic fluorescence parameters GS, PIABS, ABS/RC, and TRo/RC and the biochemical parameters NSC (p < 0.05). Studies have shown that plant biomass and physiological and biochemical characteristics jointly affect plant growth. Our research results will help in the screening of mulberry trees, providing data support for the strategic planning of subsequent breeding, and maximizing the quality and resource benefits of mulberry trees.