The development of drought-resistant tree varieties is of great significance for maintaining forest productivity in arid and semi-arid regions of China and addressing the challenges of global climate change. Populus laurifolia is distributed in the Irtysh River Basin in Xinjiang, China, has excellent characteristics such as fast growth and cold resistance. P. simonii has the characteristics of drought resistance and barren resistance, and is widely planted in northern China. In this study, the drought resistance characteristics of P. laurifolia × P. simonii F₁ progeny were comprehensively analyzed and evaluated. We investigated seven growth parameters such as high growth and relative leaf water content, six photosynthetic parameters such as net photosynthetic rate and intercellular CO₂ concentration, and five biochemical characteristics such as SOD activity and MDA content. Based on the drought resistance coefficient and membership function analysis of 18 trait parameters, the parent and 23 F₁ progeny were divided into three drought resistance types: high, medium and low. Compared to other two drought resistance types seedlings, the highly drought-resistant F₁ progeny seedlings had larger leaf thickness, upper and lower epidermis thickness, palisade tissue thickness, and leaf tissue compactness. For highly drought-resistant F₁ progeny seedlings, the expression levels of key drought resistance genes under drought stress were significantly higher than other two drought resistance types. This study provides theoretical guidance and material basis for breeding drought-resistant poplar.

The recessive nuclear male sterility line is the base of the third-generation hybrid rice breeding technology. To explore new male sterility lines suitable for the breeding technology, we screened an ethyl methylsulfonate (EMS) mutant library derived from the elite xian variety Huanghuazhan (HHZ) and identified male sterility mutant 102 (ms102). The ms102 showed a normal vegetative development, but exhibited defective anther dehiscence and pollen abortion. Cytological analyses revealed that the degradation of the tapetum was abnormal in ms102, resulting in the abortion of microspores. Genetic analyses showed that the male sterile phenotype of ms102 was resulted from the mutation of a known male sterility gene Defective Pollen Wall 2 (DPW2), which encodes an acyl transferase. Thus, this study identified a recessive nuclear male sterility mutant, and further confirmed the function of DPW2 in rice pollen development.