ISHS Acta Horticulturae 637: XXVI International Horticultural Congress: Advances in Vegetable Breeding
A PSEUDOEMBRYO HIGHLY STAINABLE WITH TOLUIDINE BLUE O MAY INDUCE FRUIT GROWTH OF PARTHENOCARPIC TOMATO |
| Authors: | K. Kataoka, H. Okita, A. Uemachi, S. Yazawa |
| Keywords: | Lycopersicon esculentum, ovule, development, auxin, pat-2 |
| Abstract:
Pseudoembryos are formed in the parthenocarpic tomato fruits of a genetic parthenocarpic cultivar ‘Severianin’ and an economic cultivar treated with auxin. We investigated histochemically the relationship between pseudoembryo development and fruit growth. Enlarging of inner integument cells was defined as the beginning of pseudoembryo formation. The non-parthenocarpic cultivar ‘Kyouryoku-Kyokkou’ tomato emasculated before anthesis began to show fruit growth immediately after the treatment with 15 mg L-1 4CPA either when treated at 0, 5 or 10 days after anthesis. In the emasculated plants of this cultivar without 4CPA treatment, inner integument cells enlarged but were stained poorly with toluidine blue O. However, when treated with 4CPA, the innermost integument cells stained well and multiplied to form pseudoembryo at 5-10 days after the treatment. In parthenocarpic tomato lines ‘MPK-1’, offspring of ‘Severianin’, the pseudoembryo formed before anthesis and developed as the stage of the ovary advanced. Another parthenocarpic line ‘HOK-12’, offspring of ‘Severianin’, usually set very small parthenocarpic fruits. In this line, the integument cells stained poorly and enlarged without cell division from 14 to 80 days after anthesis. The ovaries treated with 60 mg L-1 4CPA at anthesis reached to 2.5-3 mm in diameter 10 days later and then most of them stopped growing. In the ovary that stopped growing, there were the pseudoembryos consisting of some enlarged cells with poor stainability. In a few ovaries that continued growth, well-developed pseudoembryos were observed at 21 days after 4CPA treatment. In the ovaries of dropped fruits, there was no trace of pseudoembryo development. It was suggested that the well-developed pseudoembryo was essential for the growth and setting of parthenocarpic fruits. | |
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