Vergara - 1976 - Physiological and morphological adaptability of ri

288 CLIINIATE mo RICE
Hoyuyuhi
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Noun 2O
(Artificially liqhtldrooml
Cl- sound winnlm ,q|mnqld lm- putluns in oumn toeul:
gpqfllglg mung p; I- pan-ml a no Olhllctnm
CI- fuilin lo qummu on 9- Pfllli" “WWI”
flvqmulu I - cessation of untMI
u_ little ow no shedding of
amount-t
90"!" M “WWW Solid line indium sterling
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Days o! cooling
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3. Steriliw and male injuries at anthesis from cooling
treatment at different durations (Ito et al.. I970).
Anther injuries at anthesis
To clarity the direct cause of sterility. Ito et al. (1970) made precise observations
at anthesis on the definite locations of spikelets (see page 210, last line) cooled
at the meiotic stage. Injuries observed were arranged in developmental order
from anther differentiation to pollen germination. as follows." (l) cessation of
anther development. (2) pollen unripeness. (3) partial or no dehiseenee. (4)
pollen grains in anther loeuli. (S) little or no shedding of pollen grains on stigmata.
and (6) failure of germination on stigniata. As shown in Fig. 3. the main
cause of infertilization can be explained by the cessation of developmental
processes prior to anther dehiseence. Pollen unripcness is considered to be the
primary factor inducing anther indehiscence. This observation agrees with that
of Shimazaki, Satake, lto, Doi. and Watanabe (l 964) on the basis ofpanicle unit.
PHYSIOLOGICAL INJURIES lN COCJLED ANTHERS
When compared with lily anthers, rice anthers are strikingly minute. For example.
rice anthers at the sensitive stage are ca. l mm in length and ca. IOug in dry
weight per anther, Wl1llClllC_\g-' are ca. 2 mm and ea. 30ug at anthesis. respectively.
Such minute material makes physiological study very difficult.