The Research On The Main Physiological And Biochemical Changes Of Camellia Oleifera Fruits During Development And Ripening

Using the fruits of’Min 43’and "Min 60’ as materials, which were belong to 12-year-old clonal Camellia oleifera varieties of Fujian currently. This paper studied Camellia oleifera fruit growth and development, and the changes and mechanisms of fruit phenotypic traits、endogenous hormones、inclusions and enzymes of synthesize oil, discussed the similarities and differences between the two varieties of fruits during the growth and fruit ripening.The main results showed that:(1) The fruit growth curves of’ Min 43’ and ’Min 60’ were similar. The length and diameter of’ Min 43’ fruit exhibited S-shape curve, and its fresh fruit weight and seed weight exhibited S-shape curve too, its fruit shape showed ovate, fruit enlargement mainly focused on 10 July-10 September. The length and diameter of’ Min 60’ fruit exhibited S-shape curve, and its fresh fruit weight and seed weight exhibited S-shape curve, its fruit shape showed shape of the ball, fruit enlargement mainly focused on 26 July～10 September. On the whole, the fruits’volume and quality of these two varieties all growed rapidly before September, and essentially unchanged after September. In addition, the fruit growth rate of’ Min 60’ was slower than’ Min 43’, the lag time of different indexes were varies, and mainly in 15d to 30d, but the growth rates of different indexes were significantly higher than those of’ Min 43’ in the late fruit development, so these two species reached to developmental closely at a similar time, and reached to maturity at the same time.(2) The peak period of fruit synthesize oil of’ Min 43’and’ Min 60’ were mainly focused on 10 September～9 November (fruit ripening). Their moisture content of fresh seeds rised firstly, and than decline rapidly during the peak period of fruit synthesize oil, and reached to the lowest when the fat content reached to the highest at the time of fruit ripening. The correlation between the change of fresh seed’s moisture content and seed oil content reached a significantly negative correlation.(3) The soluble sugar contents in seeds of’ Min 43’ and ’Min 60’ all showed a tendency to rise after falling. The reducing sugar contents always showed a declining state throughout the period of growth and maturation, and reached the lowest value at the time of fruit ripening. At the same time, contents of other inclusions of fresh seeds, such as:soluble protein, soluble starch and sucrose, increased rapidly with fruit development, it suggested that the oil in fresh seed was mainly transformed from reducing sugar which belonged to soluble sugar. By comparison, the reducing sugar decrease value of’ Min 43’ fresh seed was 6.65% ,5.92% for’ Min 60’, so the fruit oil content of’ Min 43’ was higher than’ Min 60’.(4) Soluble protein and sucrose contents in seeds of’ Min 43’ and ’Min 60’ all fell to lowest value on July and August, and the fruits were in the fruit enlargement at this time, and adequate supplying of nutrients were essential for fruit growth and inflate, so the consumption of nutrients by fruit inflating fastly on July to August caused the decreasing of soluble protein and sucrose contents.(5) The ACCase and PPase activity in seeds of’Min 43’ and’Min 60’ all rised rapidly on 10 September～9 November (fruit ripening), basically coincided with the peak period of oil synthesis in seeds, the fat content and ACCase and PPase activity of seed showed a significant positive correlation. It indicated that ACCase and PPase activity promoted fat synthesis in seeds. Among them, the ACCase activity of’ Min 43’ was significantly greater than’ Min 60’, it might be one of the possible reasons of differences in fat content between’ Min 43’ and "Min 60’.(6) In peel and seeds of "Min 43’ and’Min 60’, each hormone content all was in their highest or higher level in the early growth phase (close to the young fruit stage), since then the hormone content in seeds decreased substantially, but in endocarp droped firstly and rised after. The change patterns of ZR, GA3 and IAA in these two varieties of fruit were quite similar, but the change trend of ABA showed great difference.(7)The overall hormone levels of peel and seeds were showed that:the content of ABA was the most, next was IAA, the contents of ZR and GA3 were closed at a low level, it suggested that fruit growth and development was more closely related to ABA.(8) The changes of four endogenous hormones of pericarp generally were consistent with those in seeds before fruit enlargement (mainly in July and August), and the endogenous hormones contents of pericarp were less then seeds; The changes of four endogenous hormones of pericarp generally were not consistent with those in seeds after fruit enlargement, they did not continue to decline with the decline of hormones in seeds, most were in opposite rising or steady fluctuation, and the endogenous hormones contents of pericarp were more then seeds. The changes of four endogenous hormones of’ Min 60’ fruits hysteresized then’ Min 43’, it indicated that the detention of endogenous hormones’ changes was an important reason for the delay of fruit development.(9) The correlation between peel’s GA3 contents and length of’ Min 43’ fruit reached a positive correlation, and length of’ Min 60’ fruit reached a weak correlation, it might be the reason of’ Min 43’ fruit’s length significantly larger than’ Min 60’.(10) The correlation between 4 endogenous hormones contents in seeds and fruit diameter、length、single fruit weight and fresh seed weight all reached a significant negative correlation in Camellia oleifera, but the correlations were different in peel, it showed that the differences among varieties might caused by the differences between endogenous hormones in peel during the growth and development of fruit.(11) The correlation between endogenous GA3 contents and reducing sugar contents in seeds reached a significant positive correlation, it suggested that GA3 could increase the accumulation of reducing sugar, and reducing sugar was the main substance that converted into oil, so endogenous GA3 was a key hormone in the promotion of oil synthesis in seed of Camellia oleifera.