Study On The Regularity And Mechanism Of Calcium Nutrient Accumulation During The Development And Ripening In The Fruit Of Cerasus Humilis

In this study,two types of fruits of Cerasus humilis with high and low calcium were used as experimental materials.By studying the change regularity of calcium content and calcium uptake capacity at different stages during the development of different types of fruit in Cerasus humilis,as well as the relationship between calcium accumulation uptake and calcium morphological differences and transportation,organic acids,pectin and IAA(indole-3-acetic acid),the nutrient accumulation regularity and mechanism of calcium in fruits of C.humilis were explored,which provided a basis for the nutrient regulation and further development and utilization of calcium in fruit of C.humilis.The main findings are as follows:1.During fruit development and ripening,the contents of total calcium,available calcium,pectin calcium,calcium phosphate and calcium oxalate of the two types of fruits in C.humilis showed a trend of first increasing and then decreasing,reaching the maximum value at the hardcore stage.The content of the above calcium components was higher in the low calcium type than in the high calcium type before the hardcore stage,and higher calcium type than low calcium type after hard core stage to the mature stage,and the contents of total calcium,available calcium and pectin calcium were particularly obvious.The water-soluble calcium content of the two types of fruits increased slowly,and the low calcium type was basically higher than the high calcium type.The residual calcium content showed a continuous decrease,and there was no significant difference between the two contents.In terms of calcium nutrient content,the two types of fruits had the highest total calcium content,followed by the available calcium content,the content of pectin calcium and water-soluble calcium was significantly higher than that of calcium phosphate and calcium oxalate,and the residual calcium content was extremely low.2.During fruit development and ripening,the calcium uptake activities of total calcium,available calcium,water-soluble calcium and pectin calcium of the two types of fruits in C.humilis reached the maximum at the young fruit stage,and then gradually decreased.The relative growth of calcium uptake of total calcium,available calcium,and pectin calcium reached a maximum in the hardcore stage,and water-soluble calcium reached a maximum in the mature stage.The calcium uptake rate of total calcium reached the maximum in the hardcore stage,the available calcium and water-soluble calcium reached the maximum in the mature stage,and the pectin calcium reached the maximum in the expansion stage.3.During fruit development and ripening,the contents of total calcium,available calcium,calcium pectin,calcium phosphate and calcium oxalate in the pedicel of the two types of fruits in C.humilis increased first and then decreased,and reached the maximum value at the coloring and expansion stage.The calcium content of each component showed that the low calcium type was higher than the high calcium type before the hardcore stage,and the high calcium type was higher than the low calcium type after the hardcore stage to the mature stage.The water-soluble calcium content of fruit pedicel continued to increase,and the residual calcium content continued to decrease,all of which showed that the low calcium type was higher than that of the high calcium type.The contents of water-soluble calcium,pectin calcium and calcium oxalate in the pedicel of the two types of fruits were highly correlated with the content of calcium each form of fruit,and there was a significant positive correlation between the water-soluble calcium content of the pedicel and the watersoluble calcium content of the fruit,and the negatively correlated with the content of other types of calcium,and the correlation degree of low calcium type was higher than that of high calcium type.4.During fruit development and ripening,the contents of malic acid,organic acid and NAD-MDH(nicotinamide adenine dinucleotide-malate dehydrogenase)activity of the two types of fruits in C.humilis increased first and then decreased,and both reached the maximum value at the hard ripening stage.The content of citric acid and the activity of NADP-ME(nicotinamide adenine dinucleotide phosphate-malic enzyme)both increased first and then decreased,and reached the maximum value in the hardcore stage.The contents of malic acid and organic acids were significantly higher than those in fruits with low calcium during the coloring expansion stage and hard ripening stage.The content of citric acid was significantly higher in the hardcore stage,coloring expansion stage and ripening stage,and the fruits with high calcium were significantly higher than those in the fruit with low calcium.The citric acid content and NAD-MDH activity of the two types of fruits were highly correlated with the calcium content of each type,and the soluble calcium content was significantly negatively correlated with the citric acid content and NADP-ME activity,and significantly positively correlated with the malic acid content and NAD-MDH activity.5.During fruit ripening,the contents of total pectin,water-soluble pectin,ammonium oxalate soluble pectin and sodium hydroxide soluble pectin of the two types of fruits in C.humilis increased first and then decreased.The contents of total pectin and sodium hydroxide soluble pectin reached a maximum at the coloring and expansion stage,watersoluble pectin at the hard ripening stage,and ammonium oxalate soluble pectin at the hardcore stage.Total pectin and sodium hydroxide soluble pectin were significantly higher in low calcium fruits than in high calcium fruits at the color expansion stage,and after the color expansion stage,high calcium fruits were significantly higher than low calcium fruits.Water-soluble pectin was significantly higher than that in fruits with low calcium in the hard core,coloring expansion and hard ripening stages.Ammonium oxalate soluble pectin was found to be significantly higher in high-calcium fruits than low-calcium fruits at the hardcore stage,coloring expansion stage and ripening stage.The content of various types of calcium in both types of fruit was highly correlated with the content of total pectin,ammonium oxalate soluble pectin and sodium hydroxide soluble pectin,especially available calcium,pectin calcium and calcium oxalate,but less correlated with water-soluble pectin.6.During fruit development and maturity,the IAA content of both types of fruits in C.humilis first increased and then decreased,reaching a maximum in the hardcore stage and then decreasing rapidly.The IAA content of high-calcium fruits in the young fruit stage,hard core stage and swelling and coloring stage were significantly higher than those in the lowcalcium fruit.Generally,The IAA content of the two types of fruits was highly correlated with calcium,and was highly negatively correlated with water-soluble calcium,and positively correlated with other types of calcium to varying degrees.