11.1.1 Early events

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Figure 11.1 Poor pollination (left) compared with normal pollination (right) influences seed number and hence kiwifruit development. A fully pollinated fruit carries at least a 1000 seeds spread more or less evenly lengthwise, and in about 35 locules around its circumference. Faulty pollination causes big disparities in seed number per locule (from around 30 to near zero). There is a corresponding change in relative development of adjacent tissues. Scale bar = 1 cm.

(Photograph courtesy of M. Heffer and R.L. Bielski)

Pollination, followed by pollen tube growth and fertilisation, instigates fruit growth (Figure 11.1). If pollination does not occur, flowers are shed (only rare exceptions). Nevertheless, a developmental program of gene expression for fruit growth has already been established well ahead of floral biology. Primordia may have been initiated up to six months before a particular flower opens, and ovary development continues during flower growth with ovary tissues forming late in this process. As part of that outcome, homology between leaves and sepals is noteworthy and evident in many fruits (Gillaspy et al. 1993). Sepals show leaf-like cell layers, stomata and chloroplasts.