Starch Accumulation in Integument with respect to Ovule Culture of Petunia hybrida Vilm.

Abstract

A histochemical observation of changes in starch was performed on the ovules of Petunia hybrida Vilm. which were sampled on the different days from one-day before anthesis to 7-day after anthesis in nature, and which were cultured for 4 days started from 3-day after pollination. For purpose of information, ovules of tobacco were obser-ved on the different days from the day of anthesis to 4-day after anthesis. The obser-vation was performed on the section of the ovules treated with periodic acid Schiff reaction, iodine-potassium iodize reaction or hematoxylin. The most rernarkable finding was the accumlation of starch in the integument of ovules immediately after fertilization. In the point of starch accumulation of the cultured ovules, the normal growing ovule differed from the degenerated ovule. Integumentary tapetum was irregularly hypertrophy in the ovule which contained a abnormal tissue in embryo sac. Owing to the above observation and the fact that the ile vitro development of zygote soon after fertilization was successfully obtained, provided the osmotic value of mediLl.m had been favourable, it is considered that starch accumulation in the integument was related with osmotic value in ovule. The present information shows that the responses of integument which surrounds embryo and endosperm must be paid attention to in ovule culture. Successful ovule culture may be led by devising ile vitro condition by which the integument may be sup-ported such as under nature.