온주밀감 유엽과와 직과에서의 당산특성

Abstract

The study was conducted to investigate the effect of fruit bearing type with leafy (LY) and leafless (LS) fruits on fruit growth and sugar and acid characteristics in some very early- and early-maturing satsuma mandarin cultivars. Fruit length and diameter, fruit shape index (diameter/length), and fruit weight were measured for fruit bearing type during fruit development from 70 days after anthesis (DAA) to ripening stage and fruit size ratio at ripening stage. Fruit length and diameter showed rapid increase from 70 to 100 DAA and very slow increase thereafter. Fruit shape index increased due to the growth of diameter lasting longer than length. Change of fruit weight was similar to those of fruit length and diameter. However, there was no difference in fruit growth pattern including fruit size ratio with different fruit bearing types. Total soluble solids (TSS), acidity, TSS:acidity ratio, soluble sugar and organic acid composition were also determined for fruit juice from 100 DAA to ripening stage. TSS increased and acidity decreased continuously and then TSS:acidity ratio increased with fruit development. Soluble sugar was continuously increased, whereas organic acid decreased. Theses tendencies were related to increase of sucrose and decline of citric acid, respectively. However, there was no effect of fruit bearing type on TSS, acidity, and TSS:acidity ratio, and soluble sugar and organic acid composition. Photosynthesis rate and chlorophyll index with SPAD value were evaluated from leaves adjacent to LY and LS fruits during 70 and 130 DAA. Photosynthetic rate was higher at fruit enlargement stage than that at maturation stage, whereas there was no change in chlorophyll index between two different stages. Also, photosynthetic rate and chlorophyll index were not different between leaves adjacent to LY and LS fruits. The results indicated that fruit growth including fruit shape index and size ratio, TSS, acidity, and soluble sugar and organic acid composition were not affected by fruit bearing type with LY and LS fruits.