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The rhizosheath, the layer of soil tightly attached to the roots, protects plants against abiotic stress and other adverse conditions by providing a bridge from the plant root system to the soil. It reduces the formation of air gaps between the root and soil and facilitates the transportation of water at the root–soil interface. It also serves as a favourable niche for plant-growth-promoting rhizobacteria in the surrounding soil, which facilitate the absorption of soil water and nutrients. This review compares the difference between the rhizosheath and rhizosphere, and summarises the molecular and physiological mechanisms of rhizosheath formation, and identifying the causes of rhizosheath formation/non-formation in plants. We summarise the chemical and physical factors (root hair, soil-related factors, root exudates, and microorganisms) that determine rhizosheath formation, and focus on the important functions of the rhizosheath in plants under abiotic stress, especially in drought stress, phosphorus deficiency, aluminium stress, and salinity stress. Understanding the roles played by the rhizosheath and the mechanisms of its formation provides new perspectives for improving plant stress tolerance in the field, which will mitigate the increasing environmental stress conditions associated with on-going global climate change. [ABSTRACT FROM AUTHOR]

In order to provide a theoretical basis and technical approach for the construction and regulation of medium- and high-yield population cultivation practice of wheat after rice, agronomic and physiological characteristics in medium-high yielding populations were investigated by setting different basic seedlings and cutting leaves and ears with isotope tracing method in week-gluten wheat (Ningmai 29). The results showed that the medium-high yield (yield above 7500 kg/km2) group could be achieved at medium densities (150 × 104/hm2 and 225 × 104/hm2), whose populations own suitable number of spikes, higher grain number per spike and thousand-grain weight (the larger and stronger 'sink'). Meanwhile, these two medium-high yielding populations had higher leaf area index and suitable light-transmission rate after anthesis; thus, the leaf net photosynthetic rate after anthesis was higher, and the capacity of carbon assimilates was stronger. From the 15N test, it can be seen that the relationship between individuals in the medium-high yielding population (medium-density) is more harmonious, and the plant had higher nitrogen utilization efficiency. More nitrogen is concentrated in the spike at maturity. The results of the 13C pot trials showed that the top-three functional leaves had a higher capacity for source-production, which was also the main source of post-flowering assimilates. Increasing their area to improve the 'source–sink' ratio would help coordinate the 'source–sink' relationship in the group with a stronger 'sink'. The main technical approach is to increase the area and duration of the upper-three functional leaves after anthesis on the basis of a larger sink, thus ensuring a higher source–sink ratio and a harmonious 'source–sink' relationship after flowering. [ABSTRACT FROM AUTHOR]