Vergara - 1976 - Physiological and morphological adaptability of ri

'I'l:I1\ilPER;-\'l'URE AND VEGE'1";-\'l'l\’1:'. GROWTH
indicate that comparatively low water temperatures were favorable to raising
shofl but strong seedlings.
The effect of water temperature on nutrient absorption by rice seedlings
differ among different ions. Takahashi ct al. (1955) showed that the absorption
of phosphorus was the most strongly inhibited by a low temperature (l6°C).
and the inhibition decreased in the following order: water. ammonium sulfur.
potassium, magnesium. chlorine. and calcium (absorption of the last two ions
was rather accelerated at the low temperature). Fujiwara and Ishida (1963)
reported that the inhibition of absorption was equally severe at 17°C for phosphorus.
potassium, nitrogen, iron. silicon. calcium. and magnesium for the
first 2 xveelcs after transplantation; at tillering stage, severe inhibition occurred
for phosphorus. potassium. and calcium at 17°C". the absorption of manganese
was accelerated at 17°C. At anthesis. the order of low temperature (14°C)
inhibition in salt absorption was phosphorus. ammonium. potassium. water.
magnesium. and calcium (Ishizirka and Tanaka. 1963).
Baba et al. (1953) observed high temperature inhibition of the absorption of
salts by rice plants; the degree of the inhibition was in the order of potassium
and silicon. phosphorus and ammonium. manganese and calcium. Chaudhary’
and (‘rhildyal (1970) studied the influence of soil temperature on nutrient uptake
by rice plants; nitrogen. phosphorus. and potassium were all most actively
absorbed at an average soil temperature of 26°C. and the uptake decreased at
31°. 21°. and 36°C. in that order.
Ishizuka et al. (1962) reported that a low temperature of 13°C inhibited
strongly the transloeation of carbohydrates and salts (nitrogen. phosphorus.
potassium. and calcium)". the low temperature at tillering stage resulted in a
decrease in panicle number because of the decrease in transloeation of these
substances into the growing organs.
Aimi and Sawamura (1959) studied the effect of temperature on transloeation
of "P from the flag leaf to the panicle in rice plants. They suggested that the
temperature range for effective transloeation is from l7°—18°C to 28°—29°C with
an optimum at 21—25°C. Chaudhary and Ghildyal (1970) showed that the
transloeation of nitrogen, phosphorus, and potassium into the panicle ivas the
largest at 26°C.
Cell division
Yamakawa and Kishikawa (195?) studied the influence of temperature on the
division and elongation of root cells in rice seedlings of 3-rnm plumule length.
Figure 4 shows the effect on cell division and elongation of root-tip conical cells.
Cell division was most active at 25°C; it notably decreased at 15° or 35°C. and no
division was observed above 40°C. The elongation of cells W35 largest at 30°C". it
notably" decreased at 15° or above 40°C. Consequently). the length of seminal
roots was largest at 30°C; the elongation of the roots at 15°C or above 40°C
was very slow.