猕猴桃生长过程中果肉和叶绿体的生理特性研究

Studies on Physiology Characteristic of Fruit Pulp and Chloroplast during the Growth of Kiwifruit

以“秦美”猕猴桃果实为试材,研究其盛花后70~165d生长发育过程中呼吸强度、乙烯释放量、硬度、SSC、叶绿素含量、果肉和叶绿体中POD、SOD活性和MDA、O2-·含量的变化。结果表明：在盛花后70~165 d,果实的呼吸强度先上升后下降,盛花后110 d达最大值;乙烯的释放量逐渐上升,至采收时达最大值,说明刚采收的猕猴桃果实会释放乙烯,只是含量很低;果实硬度逐渐下降,可滴定酸先上升后下降;SSC和固酸比逐渐上升,SCC与盛花后时间呈极显著的线性正相关,可根据花后时间推测秦美猕猴桃的成熟度,结合测定果实的SSC,确定果实的最佳采收期。果肉和叶绿体中O2-·含量逐渐升高。盛花后70~150 d,果肉和叶绿体中的MDA含量、POD和SOD活性逐渐升高,而盛花后150~165 d则逐渐下降。叶绿体中的POD和SOD活性,MDA和O2-·含量分别是果肉中的1/10,1/10~1/20,1/8,1/2,极显著低于果肉（P〈0.01）,其中叶绿体中O2-·含量相对较高;总Chl、Chl a、Chl b、类胡萝卜素含量逐渐上升,说明叶绿体处于正常的生理状态,稳定地进行着光合作用和色素的积累。盛花后90~150 d,各色素含量快速上升,此时应施加氮肥,以保证植物进行光合作用和叶绿素合成对氮素的需求量。

Physiology characteristic of ＇Qinmei＇ kiwifruit in fruit pulp and chloroplast were studied during the growth period of 70-165 days after full bloom, including respiratory rate, ethylene production rate, soluble solid content, firm- ness, titrable acid, chlorophyll content, activities of superoxide dismutase and peroxidase, the contents of malondialde- hyde and superoxide radical. The results showed that respiration rate reached up to the highest level at 110 days after full bloom, then started to drop; Ethylene production rate exhibited an increase trend untill the maturation of fruits, in- dicated that kiwifruit produced ethylene at early harvest but ethylene production was very little; The firmness gradually decreased; Titrable acid reached up to the highest level, then started to drop; Soluble solid content and ratio of soluble solid content to titrable acid content increased; Soluble solid content and days after full bloom had a significantly posi- tive correlation, so according to days after full bloom and SSC could forecast the maturity of ＇Qinmei＇ kiwifruit, then the best harvest time of kiwifruit could be determined; Superoxide radical content gradually increased in fruit pulp and chloroplast; During the growth period of 70-150 days after full bloom, malondialdehyde content, the activities of super- oxide dismutase and peroxidase in fruit pulp and chloroplast gradually increased; During the growth period of 150~165 days after full bloom, theses indexes gradually decreased; The proportion of activities of superoxide dismutase and perox- idase, the contents of malondialdehyde and superoxide radical in chloroplast were about 1/10,1/10-1/20,1/8,1/2 in pulp respectively, those indexes in chloroplast were significantly lower than pulp （P〈0.01）, superoxide radical content in chloroplast is relatively higher; The contents of chlorophyll a, chlorophyll b, carotinoid and total chlorophyll increased, showed that chloroplast was in normal physiological state, such as carring out photosynthesis and accumulating pigments. During the growth period of 90-150 days after full bloom all the pigmengts rapidly increased, nitrogen fertilizer should be uesd, because the accumulation of pigments and photosynthesis needed nitrogen.