关键词: 氟化钾, 氟化钾, 伤害阈值, 致死浓度, 植物, 伤害症状

Abstract: The research aims at clarifying the effect of sowing date on appearance quality and nutritional quality of maize, analyze the correlation between appearance quality and nutrition quality, and discuss the possibility of using appearance quality to predict nutritional quality. The research is developed on the natural condition of mid-late maturity maize ecological territory in loess plateau of Shanxi Province. ‘Qiangsheng 49’ and ‘Tunyu 6’ were used as material. Appearance qualities were acquired with modern image processing technology, and nutritional qualities were acquired with near infrared reflectance spectroscopy. The results were as follows: sowing date significantly affected the appearance quality of maize, the plumpness index in the suitable date (the third period) was the biggest, the longer advancing or postponing time, the worse the plumpness. Sowing date of test weight had an obvious main effect which was in single summit-shaped curve, and the peak appeared in the forth period. The density of grain was primarily influenced by variety. All characters of maize nutrition quality were strongly influenced by sowing date. Protein content of sowing in suitable date (the third period) was higher than those of other sowing date; the starch content of ‘Qiangsheng49’ showed an increasing tendency along with sowing date. The oil content of ‘Qiangsheng49’ in the first three periods was higher than those of later three periods. However ‘Tunyu6’ had bigger variations, but lack of apparent law. Negative correlation was showed obviously by the starch contents and grain length, grain area, rectangularity as well as single grain weight. The significantly positive correlation appeared in rectangularity and oil content. The protein content was significantly negative-correlated with starch content, and was positively correlated with oil content. Therefore, we can adjust sowing date in order to get higher grain quality.