伏旱高温期不同品种柑桔果面温度日变化

Diurnal Variations of Temperature on Citrus Fruit Surface of Different Varieties in Extremely Hot and Dry Summer

以温州蜜柑、脐橙和椪柑为材料,在重庆伏旱高温期间,选择晴天和阴天分别测定树冠南面朝天果顶部和基部表面温度的日变化。结果表明:3个品种的果面温度为温州蜜柑>脐橙>椪柑;晴天果实顶部日最高温一般出现在12:30—14:30;果实表面温度与气温和太阳辐射极显著正相关,气温对果面升温有显著影响,但太阳辐射对果实持续高温甚至发生日灼有更重要作用。在气温38.3℃时,温州蜜柑果顶最高温度达55.2℃,脐橙次之(54.1℃),椪柑最低(50.2℃);日灼果比例也以温州蜜柑最高,脐橙次之,椪柑最低,说明高温季节果面温度不同是这3个品种日灼率不同的主要原因。

Diurnal changes of fruit surface temperature of satsuma mandarin, navel orange and pon- kan were measured on sunny and cloudy days during extremely hot and dry summer season in Chongqing. The highest fruit surface temperature was recorded for satsuma mandarin while the low- est was recorded for ponkaru On sunny days, the highest fruit surface temperatures were recorded between 12..30 and 14：30. There was a very significant positive correlation between the fruit surface temperature and two meteorological parameters： the air temperature and the solar radiatiorL High air temperature had remarkable effect on the rise of fruit temperature, and strong solar radiation had even greater effects on the increase of fruit temperature. High fruit surface temperature induced fruit sunburn. When the air temperature was 38. 3 ℃, the highest temperature on the top surface of fruit was 55. 2 ℃, 54. 1 ℃ and 50. 2 ℃ for satsuma mandarin,navel orange and ponkan, respective- ly. The percentage of sunburned fruit was the highest in satsuma mandarin, followed by navel or- ange and ponkan. The results indicated that the differences in fruit surface temperatures were close- ly related to the differences in fruit sunburn rates of the three investigated cultivars.