Vergara - 1976 - Physiological and morphological adaptability of ri

460 (‘Llhi-XTE iwi) Ricr.
by
1 = Iue a“
where 1,, e and k stand for the light intensity outside the community, base of
natural logarithm. and light extinction coefficient, respectively.
Then the mean light intensity, l, for the whole leaf layers would be
-_l F _l0 F 3 _lgr 1 ,PF_ [u _
-
1- FL I¢IF_ Fsui- "dF- TL _Ft ~10 _ kit)
v H)
l‘or arranging the context. I and 1" can be replaced by S and .-l,
so that the following is obtained
respectively",
S‘: (I —e'*A) (1)
The value ofk for solar radiation was assumed to be 0.35 in rice stands (Murata
et al. 1966).
Using the 4-year data, 1967-1970, of the IBP field experiment, the value off‘
at various growth stages was calculated according to equation (l), and the correlation
coefficient between this and the corresponding NAR value was calculated.
Strikingly high positive correlations. all significant at 0.1 % level. except
for the single ease of Sendai. were obtained:
Akita 9344 (49) Sendai 0.069 (28)
lakada -Fukui 0.581 (36) Nagano 0.823 (36)
Konosu 0.804 (36) liukuyama (1.770 (37)
Chikugt) 0.574 (36) Pooled 0.735 (249)
(Figures in parentheses indicate the number of samples.)
The very close correlation was also observed. as shown in Fig. 4, when the
data of all the seven stations were pooled. However. those points indicated by
x marks (values observed in the 3-week period just after transplanting) seem to
be exceptions to the general tendency.
Thus, if the deviation of actual NAR values from the regression line are taken
at a given station. then it will show the influence of factors other than g at the
station at the corresponding level of §
Influence of physiological age of plants
An attempt was then made to remove the influence of the next factor. It was
reported earlier that the change with growth of photosynthetic activity of rice
leaves could be best represented by the percentage total nitrogen or protein
nitrogen content of the leaf blades (Murata et al.. 1957). The same relationships
were generally’ observed irrespective of cultural conditions or variety
(Murata. 1969; 'l'akano and Tsunoda. 1971).
Therefore, by using the analytical data, §~i\=' was calculated and its correlation
with NAR was examined. As a result. correlation coefficients considerably