Alkaline stress can induce significant injury to plants, resulting in a range of negative effects, including ion toxicity, oxidative stress, and damage from high pH values. These stress factors can substantially affect normal plant growth and development, as well as yield and quality loss. To counteract alkaline stress, plants have developed a range of defense strategies, enabling them to adapt and thrive in challenging environments. These defense mechanisms operate at multiple levels such as morphological, physiological, biochemical, and molecular. The continuous advancement of genetic engineering has enabled significant breakthroughs in enhancing plant alkali resistance through human intervention. This research provides a scientific basis for crop production and ecological environment construction, and also promotes the effective development and utilization of saline-alkali lands, improving the sustainability of agricultural production.

To study the grain-filling and dehydration characteristics of maize and their relationships with yield and screen maize varieties with high yield, high quality, and suitability for mechanical harvesting, this study systematically analyzed the grain-filling and dehydration characteristics of eight early-maturing maize varieties (LK17, BN308, KD15, LK19, G806, G723, and CH6, with DMY3 as the control) planted at the 852 Farm in Heilongjiang Province. The results demonstrated the following: (1) The filling rate of all varieties followed a single-peak curve, peaking at 20–25 days after pollination (DAP); BN308 and CH6 exhibited the highest peak filling rates (1.77 g/(100 kernels·d) and 1.67 g/(100 kernels·d), respectively). (2) Dehydration displayed a clear biphasic pattern. The rapid phase, occurring from 13 to 37 days after pollination, revealed a rate of 2.02 to 2.38 (%/d). This was followed by a slower phase after 37 days, in which the rate declined to 0.75 to 1.31 (%/d). LK19 displayed the fastest dehydration rate (0.89 (%/d)) and the lowest harvest moisture content (19.25%). (3) BN308 achieved the highest yield (13,081.58 kg/ha)-15.5% higher than the control. We clarified that the grain-filling parameters are the core driving factors for high-yield maize. Extending the active grain-filling period and increasing the grain-filling rate can significantly boost the yield, and the active grain-filling period has the greatest impact on the yield. Principal component analysis shows that the starch, fat and protein content, together with the grain-filling parameters, jointly affect the comprehensive quality of the varieties, and balanced selection is required.

Calcium ions (Ca²⁺) function as ubiquitous second messengers that translate environmental and developmental cues into spatially and temporally defined cellular responses in plants. This review summarizes the cellular architecture and molecular mechanisms that generate, shape, and terminate Ca²⁺ signals, with emphasis on plasma-membrane channels, intracellular stores, pumps, exchangers, and organelle-associated transport systems. We also examine the development of live Ca²⁺ indicators, from chemical dyes and aequorin to ratiometric and single-fluorophore genetically encoded calcium indicators, and discuss principles for selecting sensors for different tissues and subcellular compartments. Recent studies have applied these tools to abiotic stress, plant immunity, polar growth, development, symbiosis, and systemic signaling. Accurate quantitative imaging nevertheless requires careful matching of sensor properties to the target cellular environment and rigorous control of motion, spectral interference, and analytical procedures. Combining improved indicators with advanced microscopy, genetic validation, and standardized data analysis should help connect distinct Ca²⁺ signatures with their molecular origins and physiological roles.