CHANGES IN ENERGY-DEPENDENCE AND MORPHOLOGICAL-CHARACTERISTICS WITH THE DEVELOPMENT OF RICE NURSLING SEEDLINGS RAISED UNDER DIFFERENT LIGHTAND TEMPERATURE CONDITIONS
R. Sasaki et K. Hoshikawa, CHANGES IN ENERGY-DEPENDENCE AND MORPHOLOGICAL-CHARACTERISTICS WITH THE DEVELOPMENT OF RICE NURSLING SEEDLINGS RAISED UNDER DIFFERENT LIGHTAND TEMPERATURE CONDITIONS, Nippon Sakumotsu Gakkai Kiji, 66(2), 1997, pp. 252-258
The developmental changes of energy dependence, from a reliance on end
osperm to reliance on photosynthetic tissue, and the morphological cha
racteristics of rice nursling seedlings were examined. The seedlings w
ere raised in temperature-controlled greenhouses set at 30/25 degrees
C, 24/19 degrees C and 17/12 degrees C with a day/night cycle after em
ergence. The growth of the seedlings was compared to the growth of see
dlings raised under dark conditions in the same greenhouses. The relat
ionship between the consumption of endosperm nutrients and the shoot d
ry weight is represented by two regression lines for the seedlings rai
sed in light, but is represented by one regression line for those rais
ed in the dark. The slope of the regression lines in light were signif
icantly different from that in the dark after 74% of the endosperm res
erves were consumed and plant age reached 2.4. As the consumption of e
ndosperm nutrients increased, the ratio of the shoot dry weight to the
consumption of endosperm nutrients in light increased about threefold
(i.e., from 0.476 to 1.433). It is thought that this change is due to
an increase in the energy received from photosynthesis as a result of
emergence and expansion of the third leaf. Seedlings with a plant age
of 2.4 in light attained enough plant length (7cm) for the normal tra
nsplanting techniques under the three temperature conditions.