Strigolactones affect the yield of Tartary buckwheat by regulating endogenous hormone levels.

BACKGROUND: As a newly class of endogenous phytohormones, strigolactones (SLs) regulate crop growth and yield formation by interacting with other hormones. However, the physiological mechanism of SLs affect the yield by regulating the balance of endogenous hormones of Tartary buckwheat is still unclear. RESULTS: In this study, a 2-year field experiment was conducted on Tartary buckwheat (Jinqiao 2) to study the effects of different concentrations (0, 10, and 20 µmol/L) of artificial synthetic analogs of SLs (rac-GR24) and inhibitor of SL synthesis (Tis-108) on the growth, endogenous-hormone content, and yield of Tartary buckwheat. The main-stem branch number, grain number per plant, grain weight per plant, and yield of Tartary buckwheat continuously decreased with increased rac-GR24 concentration, whereas the main-stem diameter and plant height initially increased and then decreased. Rac-GR24 treatment significantly increased the content of SLs and abscisic acid (ABA) in grains, and it decreased the content of Zeatin (Z) + Zeatin nucleoside (ZR). Conversely, Tis-108 treatment decreased the content of SLs and ABA but increased the content of Z + ZR. Results of correlation analysis showed that the content of ABA and SLs, the ratio of SLs/(Z + ZR), SLs/ABA, and ABA/(Z + ZR) were significantly negatively correlated with the yield of Tartary buckwheat, and that Z + ZR content was significantly positively correlated with the yield. Regression analysis further showed that ABA/ (Z + ZR) can explain 58.4% of the variation in yield. CONCLUSIONS: In summary, by adjusting the level of endogenous SLs in Tartary buckwheat, the balance of endogenous hormones in grains can be changed, thereby exerting the effect on yield. The results can provide a new agronomic method for the high-yield cultivation of Tartary buckwheat.

Slight drought during flowering period can improve Tartary buckwheat yield by regulating carbon and nitrogen metabolism.

This study aimed to clarify the effects of drought during flowering period on the carbon and nitrogen metabolism, growth, and yield of Tartary buckwheat. Tartary buckwheat cultivar Jinqiao 2 was treated with well-watered (CK), slight soil-drought stress (LD), moderate soil-drought stress (MD), and severe soil-drought stress (SD), with the soil water potential maintained at - 0.02 to - 0.03, - 0.04 to - 0.05, - 0.05 to - 0.06, and - 0.06 to - 0.07 MPa, respectively. With prolonged growth period and an increase in drought stress, the antioxidant enzyme activities and the contents of substances and activities of enzymes related to carbon and nitrogen metabolism in Tartary buckwheat leaves initially increased and then decreased. Meanwhile, the contents of malondialdehyde and superoxide anion showed a continuous. LD treatment induced the highest antioxidant enzyme activities and the contents of substances and activities of enzymes related to carbon and nitrogen metabolism but the lowest contents of malondialdehyde and superoxide anion in Tartary buckwheat leaves. Compared with CK, LD treatment increased the grain number, 1000-grain weight (MTS), and yield per plant by 6.52%, 17.37%, and 12.35%, respectively. In summary, LD treatment can increase the antioxidant enzyme activities and the contents of substances and activities of enzymes related to carbon and nitrogen metabolism, thus enhancing the adaptability of Tartary buckwheat to drought stress and increasing the yield per plant.

[Effects of phytoremediation on soil enzyme activity and thermodynamic characteristics of enzymatic reaction in severe saline-alkali land.] / æ¤è¢«ä¿®å¤å¯¹é‡åº¦ç›ç¢±åœ°åœŸå£¤é ¶æ´»æ€§å’Œé ¶ååº”çƒ­åŠ›å­¦ç‰¹å¾çš„å½±å“.

With the environmental changes and the increases of anthropogenic disturbance, the area and degree of salinization in saline-alkaline lands of Songnen Plain have been increasing with an unprecedented rate. In this study, the effects of restoration of natural vegetation, Leymus chinensis, Avena sativa and Medicago sativa, on the enzymatic activities and thermomechanical characteristics of enzyme catalyzed reaction of two oxidoreductases (catalase, polyphenol oxidase) and three hydrolases (alkaline phosphatase, sucrase, urease) were investigated in heavily saline-alkaline soils from western Songnen Plain. The results showed that the activities of those five soil enzyme as well as the activation free energy (ΔG) increased with increasing temperature, reaching respective maximum at 40 and 45 ℃. The activation enthalpy (ΔH) and entropy (ΔS) of soil enzyme did not change with increasing temperature. The temperature coefficient (Q10) slightly changed and ranged from 1.05 to 1.36 by every 10 ℃ enhancement of temperature. Compared with the bare land, catalase activity increased in natural vegetation and L. chinensis rehabilitated land, but decreased in A. sativa and M. sativa remediation land. The change of ΔG of catalase showed a contrary trend with that of enzyme activities, while ΔH and ΔS increased in the restoration areas of L. chinensis and A. sativa, and decreased in the restoration of natural vegetation and M. Sativa. The activity of polyphenol oxidase decreased or remained unchanged in all restoration sites, and ΔH and ΔS decreased in natural vegetation and L. chinensis restoration sites, while remained unchanged in A. sativa and M. sativa restoration sites. ΔG of polyphenol oxidase reached the maximum at 40 ℃ in each restoration site and decreased or remained unchanged at other temperatures. The activities of three hydrolytic enzymes increased in each restoration site compared with the bare land, and the ΔG of the enzymes decreased or remained unchanged in each repaired area, while ΔH and ΔS varied greatly among the restoration sites. Taken together, significant responses of soil enzyme activity and their thermodynamic characteristics to temperature change and vegetation restoration were detected, which would provide better understanding for the restoration of heavily salinized soil.