Vergara - 1976 - Physiological and morphological adaptability of ri

300 curaaTF. AND RICE
and the tolerance to delayed growth-type is not so high among Hokkaido varieties.
NIANUEL: You claim that the formation of a given tapetal cell is caused by the breakdown of
the cell walls of adjacent cells. Does this occur without impairment of the integrity of the eell
membrane‘?
Salake.‘ No. The cell membrane is also broken. The broken eel] membranes reassemble to
form one huge cell. immediately afier the breaking. Therefore. free edges of cell membrane
cannot he founcL
DE DATrA: Since cool injury. drought injury and flood injury are specific at a sensitive
growth stage. do these adverse thctors affect the rice crop the same way’? If so, does Dr. Satake
have any suggestion for a common method in screening rice varieties for all these adverse
factors?
Satake: It is a very important and interesting question. To my regret, l cannot think of any
practical suggestion.
NISHIYAMA: In discussing Figure 7. you said that future studies may modify the hypothesis.
I agree. but in my opinion the modification may not be highly significant. The arrow sign
from “tapetal hypertrophy" to “suppressed pollen maturation" cannot be widened. The probable
modification is concerned only with the arrow to the ‘tapetal hypertrophy." By present
knowledge this arrow must be widened so far as the cooling treatment at the young microspore
stage is concerned.