Indole-3-acetic acid concentration and ethylene evolution during early fruit development in peach

Abstract

Ethylene evolution was measured from greenhouse-grown 'Jerseyglo' peach fruits beginning 29 days after anthesis. Indole-3-acetic acid (IAA) levels were measured in the pericarp and seed tissues of individual fruits on a single shoot when variable ethylene evolution was noted . Despite hand-pollinating all flowers on the same day, variability within the shoot existed in fruit fresh weight, IAA levels, and ethylene evolution . Seed IAA concentration increased as fruit and seed fresh weight increased and ranged from 106 to 1572 ng . g -' . As pericarp fresh weight increased, IAA levels in this tissue decreased . Ethylene evolution rates ranged from 0 .21 to 1 .07 nl. g. -'h -'and were not correlated with IAA concentration in seed, pericarp, or the whole fruit . High rates of ethylene evolution from the whole fruit occurred prior to increased IAA concentration in the seed .Fruits were excised from field-grown `Redskin' peach trees beginning 40 days after full bloom . Fruits from field sampled shoots appeared to be more physiologically advanced than the greenhouse-grown 'Jerseyglo' fruits . Pericarp IAA concentration was low, ranging from 2 .8 to 6 .5 ng. g -' . Seed concentrations accounted for 75% of the IAA found in the fruit and ranged from 239 to 1042 ng . g -' . As with greenhouse-grown samples, whole fruit IAA concentration tended to decrease as fruits increased in fresh weight . . IntroductionPeach fruit display a double sigmoidal growth curve . During Stage I, the growth of the pericarp is rapid . Stage II, or the lag phase of growth, is characterized by rapid development of the embryo, lignification of the endocarp, and decreased pericarp growth rate . The mesocarp undergoes rapid growth by cell enlargement during Stage III . The endogenous systems which regulate these stages are not known, but several scientists have described regulating roles for hormones . Jackson [8] observed high gibberellin-like activity in the pericarp of fruits during Stage I . Ethylene production also occurs at relatively high rates at that time and 1-aminocyclopropane-1-carboxylic acid concentration peaks in the fruit [9,13,14] . These increases 38 appear to be coincident with cytokinesis of the endosperm [13] . Auxin levels are also high during Stage I [14] .A positive correlation in auxin and ethylene biosynthesis has been reported in several plant organs [23] . Endogenous IAA concentrations and rates of ethylene evolution were positively correlated in studies of peach fruit development [14] . In that work, the IAA data were obtained from pooled fruit samples ; therefore, the hypothesis that variable ethylene evolution rates were positively correlated with IAA concentration of individual fruits could not be tested .The purpose of the current study was to determine if IAA concentration is positively correlated with ethylene evolution rates on a single fruit basis . Materials and methodsPlant material. One-year-old 'Jerseyglo' peach trees grafted onto 'Halford' rootstock were planted in 20 liter pots, containing a mixture of soil :...

Flower fertilization and fruit development prompt changes in free polyamines and ethylene in damson plum (Prunus insititia L.)

“…Ethylene production in S1 is perhaps needed for regulating the abundant cell division characterizing early fruit growth. Results similar to ours have been reported in peach (Miller and Walsh, 1990;Tonutti et al, 1997). However, due to the small fruit size (recently fertilized ovary), we were unable to determine the part of the fruit in S1 that was directly involved in this notable production of ethylene.…”

Changes of endogenous hormone levels in developing seeds, zygotic embryos and megagametophytes in Picea glauca

“…Actually, an increase of IAA in the seeds (on a per seed or a fresh weight basis) coincided with an increase of seed dry weight between weeks 4 to 6 AFP. The coincidence of IAA increase and seed growth between early to mid-developmental stages is also found in many angiosperms, such as Sechium edule (Di Gregorio et al 1995), peach (Miller and Walsh 1990) and tomato (Hocher et al 1992). At the late maturation stage, the decrease in embryo IAA may reflect slower embryo growth.…”

Pollination and CPPU Treatment Increase Endogenous IAA and Decrease Endogenous ABA in Muskmelons during Early Development

“…Pollination and fertilization are the main predictors of fruit growth during these early stages and it has been suggested that seed-produced auxin is involved in fruit set and development (Weaver, 1972). This view is supported by reports showing that IAA content in the seeds is higher than that in the mesocarp of strawberry (Fragaria ×ananassa Duchesne) (Nitsch, 1950), peach [Prunus persica L. Batsch (Peach Group)] (Miller and Walsh, 1990) and tomato (Lycoperisicon esculentum Mill.) (Hocher et al, 1992).…”