[Effects of exogenous methylglyoxal on chesnut seedlings under drought stress]. / å¤–æºç”²åŸºä¹™äºŒé†›å¯¹å¹²æ—±èƒè¿«ä¸‹æ¿æ —å¹¼è‹—çš„å½±å“.

Methylglyoxal (MG) is a novel signaling molecule with multiple functions in plants. To explore the effects of MG on Chinese chestnut (Castanea mollissima) under drought stress, two-year-old 'Huangpeng' chestnut seedlings were treated with 15% polyethylene glycol (PEG) coupled with MG or its scavenger N-acetyl-L-cys-teine (NAC). We measured the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), and glyoxalase enzymes, including glyoxalase Ⅰ (GlyⅠ) and glyoxalase Ⅱ(GlyⅡ). Contents of antioxidants such as endogenous MG, malondialdehyde (MDA), H2O2, and O2-· as well as the osmotic adjustment substances including proline (Pro), soluble sugar (SS), glycine betaine (GB) were also detected. The results showed that 0.5 mmol·L-1 MG significantly increased the activities of antioxidant enzymes (SOD, POD, CAT, APX, GR) and glyoxalase enzymes (GlyⅠ, GlyⅡ) in leaves of chestnut seedlings under drought stress, elevated the contents of osmotic adjustment substances (Pro, SS, GB) and antioxidant substances (ASA, GSH), and reduced the contents of MG, MDA, H2O2, O2-· and dehydroascorbate (DHA). Drought stress induced damages such as membrane lipid peroxidation and osmotic stress was alleviated by MG, leading to an overall improved adaptability of chestnut to drought stress. Moreover, the addition of MG scavenger NAC could reverse the effects induced by MG, indicating that MG had positive impacts on drought resistance of chestnut plants. Our study provided a theoretical basis for further exploring the mechanism of MG in alleviating drought stress induced symptoms in chestnut.

A new species and key to known species of the genus Conophymacris Willemse, 1933 (Orthoptera, Acridoidea, Catantopidae, Podisminae) from China.

A new species in the genus Conophymacris Willemse, 1933 from Yunnan, China is described. The new species Conophymacris reni sp. nov. is similar to C. jiulongensis Zheng et al., 2009, but differs from latter in width of vertex between eyes of male equal to 2.8 width of frontal ridge between antennae, epiproct of male width longer than length, cercus of male apical part not wider, tegmina extending over the hind margin of first abdominal tergum, hind tibia all red, epiphallus ancorae small, lower than anterior projection, lophi not acute, width of subgenital plate shorter than its length and hind margin with 1 tooth in female. Type specimens are deposited in the Natural Museum of Hebei University, Baoding, Hebei, China.