Abscisic acid in leaves of inbred lines and F1 hybrids of maize growing in the field and its relationship to diurnal and seasonal trends in leaf water potential
1988
Pekic, S. | Quarrie, S.A.
Trends in abscisic acid (ABA) concentrations and water potentials (ΨL) were studied in leaves of ten inbred maize lines and F1 hybrids, derived from four pairs of the lines, growing in the field in Yugoslavia. Plants were sampled frequently over 22 d in July/August from rainfed and irrigated plots and additional diurnal measurements were taken on 8 d during this time. Daily means of ΨL at 1000 h declined at an average rate of 0·033 MPa d−1 in the rainfed plants to reach c. — 1·6 MPa at the end of the sampling period. Irrigation maintained ΨL at c. — 1·3 MPa. Mean ABA levels at 1000 h rose gradually over the 3 weeks from c. 220 to over 420 ng g−1 d.wt in rainfed plants, whilst in irrigated plants the mean levels were around 280 ng g−1 d.wt and showed no obvious trend during the sampling period. Diurnal sampling showed that ΨL declined rapidly during the morning and rose again in the afternoon. However, average levels of ABA changed little during the day, remaining at about 260 ng g−1 d.wt in non-stressed plants and 380 ng g−1 d.wt in water-stressed plants. ΨL and ABA concentrations, meaned over all sampling occasions and irrigated and rainfed treatments, varied amongst the 14 genotypes by up to 0·48 MPa and 170 ng g−1 d.wt, respectively. Several inbred lines classified as drought resistant had higher ABA contents and/or higher ΨL than lines with the same developmental rates which were classified as drought susceptible. The pair of lines expressing the largest difference in ABA content (overall means 415 and 260 ng g−1d.wt) were different in ABA content throughout the sampling period, throughout the day and from leaf to leaf down the stem. The results are discussed in relation to ABA levels reported for other cereal species.
显示更多 [+] 显示较少 [-]