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.

The Mechanism by Which Umbrella-Shaped Ratchet Trichomes on the Elaeagnus angustifolia Leaf Surface Collect Water and Reflect Light.

Leaves are essential for plants, enabling photosynthesis and transpiration. In arid regions, water availability limits plant growth. Some plants, like Elaeagnus angustifolia, a sandy sub-tree species widely distributed in arid and semi-arid regions, have unique leaf structures to reduce water loss and solar radiation. Here, we describe the leaves of Elaeagnus angustifolia L., with special functioning trichomes. Through leaf submicroscopic structure observation, in situ water collection experiments, photosynthesis measurements, and reflection spectrum analysis, we investigated E. angustifolia leaves, focusing on their functioning trichomes. These trichomes capture water vapor, reflect UV and NIR light, and possess a 3D interface structure composed of 1D and 2D structures. The 1D conical structure captures water droplets, which are then gathered by the radial conical structure and guided towards the stomata through wedge-shaped grooves on the 2D umbrella structure. The trichomes also reflect sunlight, with micropapillae reflecting UV light and the umbrella structure reflecting NIR light. These mechanisms reduce leaf temperature, respiration, and water transpiration, protecting against solar radiation damage. This study provides insights into water collection and light-reflection mechanisms, revealing adaptive strategies of plants with large leaves in arid regions.

Characterization of the complete chloroplast genome of Oxytropis aciphylla Ledeb. (Leguminosae).

To better understand the taxonomy of the genus Oxytropis, we sequenced the complete chloroplast genome of Oxytropis aciphylla Ledeb. The total plastome of O. aciphylla Ledeb. is 122,121 bp in length with a GC content of 34.3%. It contains one large single-copy (LSC) region of 88,235 bp, one small single-copy (SSC) region of 10,400 bp, and one inverted repeat (IR) region of 23,486 bp, encoding 76 proteins, four rRNAs, and 29 tRNAs. The phylogenetic position shows that O. aciphylla Ledeb. is the closest to Oxytropis glabra.

Characterization of the complete chloroplast genome of Astragalus galactites (Fabaceae).

Astragalus galactites is a medicinal plant. The total plastome length of A. galactites is 126,117 bp. It contains a large single-copy region of 69,805 bp, two inverted repeat regions of 20,638 bp, and a small single-copy region of 15,036 bp. The cp genome contains 110 complete genes, including 75 protein-coding genes (75 PCGs), 4 ribosomal RNA genes (4 rRNAs), and 30 tRNA genes (30 tRNAs). The overall GC content of cp DNA is 33.9%, the corresponding values of the LSC, SSC, and IR regions are 33.0%, 30.4%, and 43.3% respectively. The phylogenetic tree shows that A. galactites has the closest relationship with A. laxmannii.

Impact of vermiculite on ammonia emissions and organic matter decomposition of food waste during composting.

This study investigated the effects of adding vermiculite to the food waste composting process. Four treatments with varying vermiculite percent compositions, 0%, 5%, 10% and 15% (w/w, wet weight of food waste basis) mixed with initial food waste were designed and then composted for 42 days. Results show that adding vermiculite prolongs the thermophilic phase, speeds up the organic matter loss, reduces the NH3 emissions and electrical conductivity values. Compared to the control, the amount of nitrogen loss through NH3 emissions in the treatments of 5%, 10% and 15% vermiculite decreased by 9.89%, 26.39% and 18.65%, respectively. Finally this work suggests that vermiculite is a suitable additive for food waste composting, especially when the makeup of the compost is 10% vermiculite.

Insight into litter decomposition driven by nutrient demands of symbiosis system through the hypha bridge of arbuscular mycorrhizal fungi.

Arbuscular mycorrhizal fungi (AMF) play an important role in litter decomposition. This study investigated how soil nutrient level affected the process. Results showed that AMF colonization had no significant effect on litter decomposition under normal soil nutrient conditions. However, litter decomposition was accelerated significantly under lower nutrient conditions. Soil microbial biomass in decomposition system was significantly increased. Especially, in moderate lower nutrient treatment (condition of half-normal soil nutrient), litters exhibited the highest decomposition rate, AMF hypha revealed the greatest density, and enzymes (especially nitrate reductase) showed the highest activities as well. Meanwhile, the immobilization of nitrogen (N) in the decomposing litter remarkably decreased. Our results suggested that the roles AMF played in ecosystem were largely affected by soil nutrient levels. At normal soil nutrient level, AMF exhibited limited effects in promoting decomposition. When soil nutrient level decreased, the promoting effect of AMF on litter decomposition began to appear, especially on N mobilization. However, under extremely low nutrient conditions, AMF showed less influence on decomposition and may even compete with decomposer microorganisms for nutrients.