The Response of Oxytropis aciphylla Ledeb. Leaf Interface to Water and Light in Gravel Deserts

In arid areas, the scarcity of rainfall severely limits the growth of plants in the area. In arid sandy deserts, plants survive by deeply rooting to absorb groundwater. In arid gravel soil deserts (Gobi), the gravel in the soil layer limits the growth and water absorption of local plant roots. Therefore, the strategies adopted by local plants to obtain water to sustain life have become crucial. Oxytropis aciphylla Ledeb. is a perennial, strongly xerophytic, cushion-shaped semi-shrub plant widely distributed in arid gravel desert areas. Its plant height is relatively short, its crown width is not large, and its root system is also underdeveloped. There are small and curly pinnate compound leaves and dense hairy fibers on the surface of the leaves. In this study, we focused on the function of leaf surface trichomes by observing the leaf submicroscopic structure, conducting in situ water harvesting experiments, measuring reflectance spectra, and analyzing chloroplast genomes of O. aciphylla leaves. The experimental results indicate that the surface of the leaves of O. aciphylla is densely covered with hair-like fiber arrays, and these hair-like fiber surfaces have micro and nanoscale protrusions. These structures can quickly capture moisture in the air and filter out ultraviolet and infrared rays from the sun, without affecting the normal photosynthesis of the chloroplasts inside the leaves. The important findings of this study are the nanostructures on the surface of the hair-like fibers on the leaves of O. aciphylla, which not only have a water capture function but also reflect light. This has important theoretical significance for understanding how plant leaves in gravel deserts adapt to the environment.