Maize (Zea mays L.) is one of the most important crops worldwide and is a model organism among cereal crops. Abiotic and biotic stresses are often present simultaneously and severely influence maize production, causing great yield losses worldwide. Therefore, the selection and cultivation of stress‐tolerant maize lines that adapt to various stresses is instrumental in addressing the problem of yield losses caused by stress. The maize mesocotyl is the crucial organ that pushes shoots out of deep water or soil after seed germination. It has a simple anatomy and exhibits rapid growth in the dark. In this article, we reviewed the studies on the elongation of the maize mesocotyl and the actions of phytohormones, especially under deep‐sowing conditions, and emphasized the role of the maize mesocotyl in response to environmental stress and deep‐sowing tolerance. We propose that the maize mesocotyl can serve as a selection organ for evaluating stress tolerance at the early seedling stage. We also identify future research fields that need further investigation in studies of the maize mesocotyl.

Starch is the major form of carbohydrate storage in plants and exists as discrete starch granules (SGs). Isolation of high-quality SGs in different plant tissues is a prerequisite for studying the roles of SGs during plant growth, development, and responses to abiotic stress. However, it is difficult to isolate transitory SGs from leaves and storage SGs from pollen grains due to their small sizes and low quantities. Herein, we develop a novel method for isolating SGs by using the aqueous two-phase system (ATS) of ethanol/NaH 2 PO 4 . The ATS method efficiently separated SGs from contaminants based on their differences in density, solubility, and polarity. Using this method, we first isolated and purified three kinds of SGs from maize seeds, pollen, and leaves. The biochemical, microscopic, and proteomic analyses demonstrated the high purity of the isolated SGs. Proteomic analysis revealed distinct differences in SG-bound proteins between seed SGs and pollen SGs. As a simple, rapid, and low-cost method, the ATS-based method exhibits highly universal and reproducible results for starch-containing tissues in various plant species.

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