Vergara - 1976 - Physiological and morphological adaptability of ri

Effects of temperature on the
vegetative growth of rice plants
I. Nishiyama
SUMMARY
he effect of temperature on vegetative growth of rice plants was reviewed. considering
gemiination. early growth. rooting, tillering. and other characteristics.
The etfect of temperature is comprehensively‘ summarized as tblltivrs:
l. Four critical temperatures have generality" through different physiological
properties of rice plants: namely. 0“—3"‘.l5""~l8“. 30“~33"" and 45‘48“C.
2. Many’ of the physiological processes of rice plants can occur over the temperature
range from O"'—3“C to l45“‘—l48"C. at least. under some conditions.
3. However, the favorable temperature range for physiological processes of rice
plants is from l5‘AlB"’C to 3U‘i’~33“C.
These critical temperatures can be applied also to various properties of reproductive
growth of rice plants. These critical temperatures can be shifted to the side
favorable to rice production by improvements of the variety or the cultivation
method; however. this shitting may not he more than a few degrees.
Within the optimal temperature range {from ISCPIS“ to 30"'—33‘C). higher temperatures.
in general. favor the growth and development oi‘ rice plants. However.
the growth of roots has an optimal temperature around 25"‘C. and lower temperatures
are favorable to raising strong seedlings. There is a controversy about the
elTect on tillering of temperature within this range.
INTRODUCTION
Temperature is one of the major factors affecting rice production. The rice
plant is cultivated ividely from tropical through temperate climates. though it
originated in the tropics. It is cultivated even in some subarctic regions. such as
Hokkaido island in itorthernmost Japan. This shovas the high adaptability of the
rice plant to wide climatic ranges.
Nevertheless. rice plants have ciptimal temperature ranges for their growth
and development. Both tiverly high and overly low temperatures are unfavorable
for rice production. Cool weather damage is not only awfully severe in Hokkaido.
but also occurs widely in cooler areas of temperate Zone regions and in
tnountainous areas in lott-"er latitude regions.
I. Alixzhri-“ama. Ilokkaido Agricultural Experiment Station. Ilistujigaoka. Toyohirzt. Sapporo. Japan