Energy-Saving Night Temperature Regime for Satsuma Mandarins (Citrus unshiu Marc.) Grown in a Plastic House with Heating. III. Application of Different Night Temperature Patterns

In order to control nighttime temperatures with energy saving, how different night temperature regimes affected on the fruit growth, quality and super(13)C allocation from leaf to fruit were researched by both the partial heating and whole tree heating. One type, altering time of nighttime heating, the end of day (EOD) -heating, middle of night (MON) -heating, and predawn (Pd) -heating were applied. The EOD-heating temporally activated the fruit growth and accelerated the super(13)C allocation from leaf to fruit through short term (hours) researches by the partial heating, however, comparing to the conventional heating as 20 degree C constant in nighttime by the whole tree heating during 60-90 days after full bloom (DAFB), no superiority was observed in both the fruit volume increase and fruit quality, and the MON-heating showed the depression of fruit growth. Another type of a regime determined by daily integrated solar radiation, comparing to the conventional heating as 17 degree C constant in nighttime during 78-120 DAFB, no superiority was observed in the fruit quality. Nighttime super(13)C allocation from the leaf to fruit was detected at 90 DAFB, though was hardly detected at all at 120 DAFB regardless of night temperatures as high as 25 degree C at both days.