H. Takahashi et al., EFFECTS OF ABA APPLICATION TO THE CULTURE SOLUTION ON THE GROWTH, WATER RELATIONS AND TEMPERATURE STRESS IN TOMATO PLANTS, Engei Gakkai Zasshi, 62(2), 1993, pp. 389-397
Effects of abscisic acid (ABA) applied to the culture solution on the
growth, water relations and temperature stress in tomato plants were i
nvestigated. 1. Plant growth was strongly inhibited when plants were p
laced in culture solutions containing 5 and 10 ppm ABA ; it was slight
ly promoted in culture solutions of 0.1 ppm ABA primarily because root
growth was stimulated. 2. ABA suppressed the water absorption by root
s and reduced transpirational loss from detached leaves. The leaf temp
erature of ABA treated plants during the day was several degrees highe
r than that of untreated ones depending on ABA concentrations. At 0.1
ppm ABA, the a-naphthylamine oxidizing activity of roots and the forma
tion and growth of adventitious roots were enhanced. 3. At 0.5 ppm ABA
, cold hardiness of tomato seedlings increased with a corresponding sm
aller loss of water from detached leaves and higher a-naphthylamine ox
idizing capacity of roots, as comparison with untreated plants. 4. On
plants exposed to high temperature, ABA treatments advanced tomato fru
it maturity with a concomitant increase in sugar content of fruit. It
was obseved that 0.1 ppm ABA treatment tended to increase fruit yield.