Early growth and development of the olive fruit mesocarp

Abstract

SUMMARY

We examined growth and development of the ‘Manzanilla’ olive fruit mesocarp in transverse equatorial sections during the first 12 weeks after full bloom (AFB). Sequential sampling and quantitative data provided an integrated view of the formation of this tissue. The mesocarp, or fruit flesh, was formed by relatively isodiametric parenchyma cells with a small number of isolated sclereids. By four weeks AFB a gradient in cell size characteristic of mature olive fruits began to appear. Biweekly measurements of cell size and number indicated that, as in other drupes, both cell division and expansion contribute to initial mesocarp growth. From six weeks AFB, further mesocarp growth was determined solely by cell expansion. Transverse areas of mesocarp and endocarp, also measured biweekly, revealed that both tissues expand in a similar manner until eight weeks AFB, after which mesocarp growth predominated.