Studies On The Changes Of Cell Wall Enzymes Activity And Endogenous Hormones Content During Fruit Development In Zaomi Pear

In this experiment,the material was 5-year old 'Zaomi pear'.We had determined the main inclusion of fruit,the indol-3-acetic acid(IAA),gibberellins(GA₃),zeatin(ZT), abscisin acid(ABA) of endogenous,and the pectinesterase(PE),polygalacturonase(PG), cellulase(Cx) of cell wall during the period of fruit development.According to the results of the determination,we analyzed the changes law and characteristics of fruit inclusion,the content of endogenous hormones,and the activity of cell wall enzymes during the period of fruit development.The coefficients of correlations showed that the content and ratio of endogenous hormones,the content and scale of endogenous hormones,the content and ratio of endogenous hormones.The regression analysis showed that the activity of cell wall enzymes and the content of endogenous hormones.We also analyzed the effects of endogenous hormones and cell wall enzymes on fruit development.Those results of researches showed that:1.The growth curve of fruit showed the model of "S" growth type in Zaomi pear,it was obviously three developmental periods.The period of fruit growth was about 100 days. The rapid expanding period of fruit was on the 10 days～30 days after anthesis,the slow growth period of fruit was on the 30 days～50 days after anthesis,and the mature anterior growth period of fruit was on the 50 days～100 days after anthesis.2.The contents of soluble sugar,fructose,glucose,and sucrose increased along with the continuous days during the period of fruit development.Sugar composition was mostly fructose in Zaomi pear fruit,the second glucose,and the sucrose was lowest.The content of soluble protein had two peaks;it reached the highest of content on 20 days after anthesis, then,there was a gradually low,but the content of protein increased on 60 days after anthesis.The content of free amino acid decreased sharply on the 10 days～50 days after anthesis,and it increased slowly on the 50 days～100 days after anthesis.The content of free nucleic acid had three peaks,the first period on 10 days after anthesis,the second on 50 days after anthesis,the third 90 on days after anthesis,and the highest of content on 10 days after anthesis.3.Content of endogenous hormone reached to peak on different period;there were differences in their highest scale in four endogenous hormones.In flesh,the IAA content was on the 50 days after anthesis.The highest scale of IAA content was 58.6%.The peak of GA₃ content was on the 20 days after anthesis,the highest scale of GA₃ content was 42.1%.The peaks of ZT and ABA were separate on the 40 days and 80 days,the highest scale of ZT and ABA was separate to 39.7%and 49.1%.In seed,the IAA content was peaks and 20 days after anthesis.The highest of scale of IAA content was 65.1%.The peak of GA₃ content was on the 60 days after anthesis,the highest of scale of GA₃ content was 31.7%.The peaks of ZT and ABA were separate on the 40 days and 90 days,the highest of scale of ZT and ABA was separate to 43.4%and 52.1%.Analysising the changes law of each endogenous hormone and their sacle in four endogenous hormones,we came to the conclusion:there was closely interrelation of IAA in the prophase and metaphase of fruit development.The scale of IAA content in four endogenous hormones was decrease along with the continuous days during the period of fruit development.There had a closely interrelation between GA₃ and fruit development on the prophase and middle-later period.The ZT content of flesh and seed were significantly different before 40 days after anthesis,the scale of ZT content was higher on the metaphase, and there were lower on the anaphase of fruit development.But the ABA content of flesh and seed were no significant change before 50 days after anthesis.The scale of ABA content in four endogenous hormones was lower on the prophase and metaphase,and there was higher on the anaphase of fruit development.4.The ratio of IAA/ABA,GA₃/ABA,ZT/ABA and(IAA+GA₃+ZT)/ABA in flesh and seed were higher on the prophase and metaphase of fruit development than the anaphase,and those showed that they played an important role in cell divisions and cell expansions of fruits.The coefficients of correlations showed that there had a complex positive and negative correlation between four endogenous hormones and their ratio.So, we could know that,the changes of endogenous hormones ratio showed that there was a dynamic balance relationship each other between the hormones of growths promote(IAA, GA₃,ZT) and the hormones of growth inhibition(ABA) during the period of fruit development,and the relative content of endogenous hormones was more important than absolute content. 5.During the period of fruit development,the activity of pectinesterase(PE) had three peaks,the first one was on 10 days after anthesis,the second on 70 days after anthesis,the third on 100 days after anthesis,and the highest of activity appeared on 100 days after anthesis.The PE had the most important effect on the prophase and anaphase of fruit development.The activity of polygalacturonase(PG) was lower on the prophase,it was higher on the metaphase,and the activity on the anaphase was higher than the prophase,and the highest of activity was on 50 days after anthesis.It proved that there had a closely interrelation between PG and fruit development on the metaphase and anaphase. The activity of cellulase(Cx) was increases along with the continuous days during the period of fruit development,and the highest activity was on 90 days after anthesis.So the PE and PG might be the key enzymes of affecting fruit ripening and softening in Zaomi pear.6.The analysis of regression showed that the activity of PE was mainly regulated by ABA,GA₃ and ZT,and the rate of contribution of ABA to PE was the biggest in turn more than GA₃ and ZR.The activity of PG was mainly regulated by IAA and GA₃,and the rate of contribution of GA₃ to PG was more than IAA.Moreover,the activity of Cx was mainly regulated by IAA and ABA,and the rate of contribution of ABA to Cx was more than IAA. So,each endogenous hormone improved the activity of cell wall enzymes,accelerated the material metabolism,and then,promoted the growth and development of fruit.7.The growth and development of fruit and the activity of cell wall enzymes were regulated by endogenous hormones.The activity enhancement of PE was regulated and promoted by ABA,GA₃ and ZT.The activity enhancement of PG was regulated and promoted by GA₃ and IAA.The activity enhancement of Cx was regulated and promoted by ABA and IAA.So,there was a common action between endogenous hormones and cell wall enzymes on the cell divisions phase,cell expansions phase,and the fruit ripening, softening phase during fruit development.