Vergara - 1976 - Physiological and morphological adaptability of ri

RICE PRODLYt“.TI\-"'ITY' IN ('3I.II\-I.ATI(1' REGIONS oF JAPAN 463
Deviation of NAR from regressions
IO
O
IO -
0 Tukodu Fukui
A Fukuyornu
I’ Chikigo
_ 2Q | I
IO i5 2O 25
Minimum
temperature PC}
6. Relationship between average minimum temperature
and the deviation of XAR from regression on 5' A7
at each station in the 3-week period starting from transplanting
{h-"Iurata. I974). Correlation coefficient, 0.932.
significant at 0.1 percent level.
Here. let me consider the meaning of "physiological state of the leaves."
When the correlation coefficient of NAR tvith S‘ - JV was compared with that with
S ~ A". the former generally proved to be higher than the latter. For example, in
the pooled data. the correlation coefficients were 0.890 vs. 0.859. That is. the correlation
of NAR became higher when M calculated from the number of days
from transplanting, was used instead of N itself to combine with S. Considering
that a sufficient supply of nitrogen xvas provided during the experiment, this
may be interpreted to mean that the physiological state of leaves which is represented
by N is actually the physiological age of the plant. The curve obtained
earlier by Murata (1961) representing the relationship between photosynthetic
activity’ and plant age is quite similar in shape to the curve represented by
equation (2). This may give further support for the above interpretation.
At Sendai, as at other stations, NAR did not show any regression on S‘, but
the regression of NAR on S - N or S - N proved to be reasonably’ close.
Influence of temperature on NAR
In Figure 4. the points representing values obtained just after transplanting
apparently diverge from the general trend, suggesting the existence of another
factor different from the three already mentioned. I have concluded that the
factor must be temperature because a linear relation was found (Fig. (i) between
the deviation of NAR from the regression line of individual stations and the
average minimum temperature of the 3-week period just after transplanting. In