Water stress is one of the most important factors limiting sustainable crop production. Therefore, the effects of the plant growth regulators (PGRs) fulvic acid (FA), brassinolide (BR), and uniconazole (Uni) on seedling growth and physiology of two maize (Zea mays L.) varieties were evaluated under???0.7 MPa water stress induced by polyethylene glycol-6000. Under drought stress, the PGRs promoted seedling growth, altered the root-to-shoot ratio, and significantly increased root biomass, length, surface area, diameter, and volume. In addition, depending on the PGR, net photosynthesis rate, SPAD value (indicating chlorophyll content), and water use efficiency increased significantly, under drought stress, whereas transpiration rate decreased. The PGRs also significantly increased antioxidant enzyme activities and significantly decreased malondialdehyde accumulation in leaves and roots under drought stress. Zhengdan958 showed greater variation in physiological responses and stronger drought resistance than Xundan20. In alleviating drought stress in maize seedlings, FA had the greatest effects on shoot growth and leaf physiology; Uni exerted its effects by regulating root structure, and BR effects were intermediate. Under drought stress, the three PGRs increased maize seedling growth, which reduced drought stress-induced damage and improved plant ability to resist the adversity. Based on a comprehensive analysis of physiological indices of drought resistance, Uni is recommended as the best PGR to improve maize seedlings resistance to drought.
Harpapion safranum
sp. n. and Harpapion borisi
sp. n. are described and figured. Harpapion vietnamense (Korotyaev, 1987) is recorded as new for China. The genitalia andterminalia of H. considerandum, H. coelebs andH. vietnamense are redescribed and redrawn. The diagnostic characters of Harpapion are defined. A key to the known species of the genus Harpapion from China is provided. Affinities with the genus Flavopodapion Korotyaev, 1987 are discussed. 相似文献
Mitochondria need to be fragmented prior to engulfment by phagophores, the precursors to autophagosomes. However, how these 2 processes are finely regulated and integrated is poorly understood. We have shown that the outer mitochondrial membrane protein FUNDC1 is a novel mitochondrial-associated membrane (MAM) protein, enriched at the MAM by interacting with the ER resident protein CANX (calnexin) under hypoxia. As mitophagy proceeds, it dissociates from CANX and preferably recruits DNM1L/DRP1 to drive mitochondrial fission in response to hypoxic stress. In addition, knocking down of FUNDC1, DNM1L or CANX in hypoxic cells increases the number of elongated mitochondria and also reduces the colocalization of autophagosome and mitochondria, thus preventing mitophagy. These findings identify FUNDC1 as a molecular hub integrating mitochondrial fission and mitophagy at the MAM in response to hypoxia. 相似文献
In hypoxic cells, dysfunctional mitochondria are selectively removed by a specialized autophagic process called mitophagy. The ER–mitochondrial contact site (MAM) is essential for fission of mitochondria prior to engulfment, and the outer mitochondrial membrane protein FUNDC1 interacts with LC3 to recruit autophagosomes, but the mechanisms integrating these processes are poorly understood. Here, we describe a new pathway mediating mitochondrial fission and subsequent mitophagy under hypoxic conditions. FUNDC1 accumulates at the MAM by associating with the ER membrane protein calnexin. As mitophagy proceeds, FUNDC1/calnexin association attenuates and the exposed cytosolic loop of FUNDC1 interacts with DRP1 instead. DRP1 is thereby recruited to the MAM, and mitochondrial fission then occurs. Knockdown of FUNDC1, DRP1, or calnexin prevents fission and mitophagy under hypoxic conditions. Thus, FUNDC1 integrates mitochondrial fission and mitophagy at the interface of the MAM by working in concert with DRP1 and calnexin under hypoxic conditions in mammalian cells. 相似文献
There are four species of Gymnetron in China recorded to date including Gymnetronmiyoshii Miyoshi, 1922, Gymnetronvillosipenne Roelofs, 1875, Gymnetronauliense Reitter, 1907 and Gymnetronvittipenne Marseul, 1876, of which the last two are new country records. The pre-imaginal stages including eggs, mature larvae and pupae of Gymnetronmiyoshii, Gymnetronauliense and Gymnetronvittipenne are described and illustrated. In addition, their diagnostic characters (larvae and pupae) are discussed and differentiated, and notes on some of their biological parameters are provided. Potential ecological impacts between Gymnetron weevils and their host Veronica spp. also are provided. 相似文献