MECHANICAL PROPERTIES OF ORANGE PEEL AND FRUIT TREATED PRE–HARVEST WITH GIBBERELLIC ACID

摘要: Mechanical property data of citrus peel and fruit are limited. Gibberellic acid (GA3), a plant growth regulator, is applied to fruit, in part, because it is believed improve integrity, yet studies characterizing effects of GA3–treatment on mechanical properties lacking. The effect GA3 treatment the mechanical properties Valencia orange (Citrus sinensis) was tested. Trees were treated with before, at, or after peel color break fall 1998, non–treated, their harvested 23 April (mid–season) 13 May (late–season) 1999. Peel samples subjected shear tensile tests, whole fruits compression and cutting tests. magnitude whole–fruit decreased between harvests, but more treatment observed second harvest than first. Treatments affected more fruit. were poorly correlated thickness, probably tissues composing not equivalent. earliest application date most effective. On harvest, before color had 10% greater rupture force (in shear) 15% strength non–treated while the similar. later GA3 before color while at color break generally that were 20% control especially harvest. Fruit before also had apparent modulus elasticity higher other