In order to investigate the physiological injury of barley caused by the low temperature after herbicides, tillering barley seedlings planted in plastic cups were pretreated in illumination incubator at 15℃ and 12 h-light per day for 7 days, and then subjected to herbicide treatment, prometryn （with the concentrations of 0, 0.15%, 0.30%, and 0.45%） or isoproturon （with the concentrations of 0, 0.30%, 0.60%, and 0.90%）, and the SOD activity, the CAT activity, the POD activity, the MDA content, proline content, soluble protein content, electrical conductivity, and the rate of O2 were determined and analyzed. The results showed that the low-temperature was the most important, and the treatment-time of low-temperature was another significant influencing factor on the physiological and biochemical indices of barley seedlings. However, all of the physiological and biochemical indices determined were not affected by the kinds of herbicides and herbicide concentrations, and the SOD was stable and should play the more prominent role on extracting of free radicals according to the stepwise regression and correlation. The herbicide concentrations should be increased in the future research for truly reflecting the effects of the herbicide concentration on the physiological and biochemical indices of barley seedlings.
Local climate conditions and sowing time are very important to the vernalization and summer reproduction of the wheat. Xundian County is located in Yunnan Province of China, at latitude 25.56° north and longitude 103.25° east. Xundian County is situated 1 873 m above sea level, and is conducive for the summer reproduction of the wheat. To investigate the optimal sowing time, 11 spring wheat cultivars and one semi-winter wheat cultivar were sown 10 times at an interval of fi ve days from May 26, 2012, and the strong winter wheat Suyin 10 was treated in a vernalization room at 2℃ with different concentrations of the gibberellin and 5-azacytidine. The results showed that Suyin 10 should be vernalized at 2℃ for 30 days in summer, and the growth periods of strong winter wheat plants could been shortened if treated with a specifi c concentration of the gibberellin and 5-azacytidine at a low temperature. The growth period of the spring wheat in summer reproduction was delayed, and their agronomic traits gradually decreased with the passage of the sowing time. Thus, spring wheat should be sown at the earliest time possible for better yield. June 25 should be the latest date for summer reproduction of the wheat, but the semi-winter wheat cultivars in Xundian County should be added generation in summer after being treated at 2℃ for 10 days. Xundian County is a suitable location for summer reproduction of the wheat in China.
Experiments were conducted to evaluate the physiological and the biochemical characteristics of waxy wheat seeds under accelerated aging conditions. Five waxy wheat lines, which were Waxy 1, Waxy 4, Waxy 8, Waxy 9, and Waxy 15; and five non-waxy wheat lines： S-39, 04J89, Jan-81, III42-4, and II110 were studied. The seeds were subjected to accelerated aging at 40℃, 45℃, 50℃, 55℃, and 60℃, and 90% relative humidity for 0, 2, 4, 6, and 8 days, respectively. The results showed a gradual increase in conductivity and decrease in germination rate during accelerated aging. SOD, POD and CAT activities increased at lowgrade treatment, but decreased at severe treatment. On the other hand, the soluble protein content decreased at 45 ℃, but successively increased, then decreased 50℃. From the above study, it showed that 90% RH at 55℃ was the best accelerated aging condition for optimum efficiency in a shorter period.
