Galactomannan metabolism in the endosperm of developing normal and mutant (makapuno) and germinating normal coconuts

Carbohydrates analysis of developing coconut endosperm showed that makapuno had higher total soluble sugars and hydrolyzable polysaccharides than normal. Similarly, carbohydrate analysis of coconut water indicated that total soluble sugars were 41.42 mg/ml in the normal at 7-8 mo while it was 12.57 mg/ml in makapuno. Also, the total carbohydrates in the normal was 27.06 mg/ml at 11-12 mo while it was 120.90 mg/ml in makapuno. Fractionation of the 8-9 mo and 10-11 mo normal and makapuno coconuts showed that total galactomannans decreased from 73% at 8-9 mo to 33% at 10-11 mo in the normal while it increased in makapuno from 61% to 72%. However, mannan content in the normal increased from 17% at 8-9 mo to 64% at 10-11 mo while mannans in makapuno decreased from 32% to 14%. Proximate analysis of normal and makapuno tissue slices showed that there was no difference between the two types of nuts. Moisture and ash were found to be high in the part of the endosperm near the water while fats and proteins were high near the shell. Carbohydrate content of the endosperm showed that makapuno had higher total soluble sugars and hydrolyzable polysaccharides. Also, all of the sugars with the exception of non-reducing sugars were found to be highest at the portion near the water. Physical measurements of germinating coconut indicated that there was a decrease in weight of the endosperm. The weight of the haustorium increased, while the weight of water decreased. The coleoptile increased at 6.0 mo. Beta-mannanase activity in germinating coconut increased in the endosperm at 6.0 mo while in the haustorium, the activity increased from 55.34 milli unit/mg protein at 0.5 mo to 138.12 milli unit/mg protein at 6.0 mo. Beta-mannosidase activity was found to increase in the endosperm while in the haustorium, the enzyme decreased.