Relation between hormonal balance and polygalacturonase activity in grape berry.
Keytieux C., Geny L., Doneche B.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004. page 11
2004
บทคัดย่อ
Relation between hormonal balance and polygalacturonase activity in grape berry.
Grape berry (
Vitis vinifera L.) is considered as a non climacteric fruit.It exhibits a double sigmoid pattern of growth.The first phase correspond to cellular multiplication and growth.Ripening occurs concomitantly with the second growth phase and involves significant changes.Sugar accumulation and colour change are well known.Softening involves variations in properties of cell wall polymers but the implicated mechanisms are still unclear.
The free acid abscissic (ABA) content of whole berry and separated pericarp increases during veraison and the ABA accumulation isconcomitant with a peak in the acid indole acetic level.Our results indicate that the pulp looses its ABA during ripening.At contrary, ABA increases in the skin.Calcium ions evolve in the same way.In the opposite the skin tissue water decreases.
ABA may involved protein synthesis such as cell wall-modifying enzymes.Polygalacturonase (PG) activity is detected during the change of colour and is seemed to be correlated with ABA levels in the berry.We observe two kinds of evolutions : in several cultivar, the berries show an increase of PG activity during veraison whereas this activity appears earlier, at the beginning of veraison for other Bordeaux cultivars.This results are also well correlated with free acid galacturonic levels in berry must.