چکیده:
To study the effects of halopriming and hydropriming in overcoming salt and drought stress in corn (Zea mays L.), two experiments were separately conducted at Shahrood University of Technology. Seed treatments consisted of control (untreated seeds), soaking in distilled water for 32 h (hydropriming), and soaking in 50 mmol solution of CaCl2 for 16 h (halopriming). Germination and early seedling growth were studied using distilled water (control) and osmotic potentials of -0.4, -0.8, and -1.2 MPa from NaCl (salinity stress) and polyethylene glycol [PEG 6000 (drought stress)]. Results showed that in both salinity and drought experiments, germination percentage reduced
significantly according to decreased osmotic potential. Hydroprimed and haloprimed seeds achieved the minimum reductions in germination percentage. The maximum reduction in germination percentage was recorded from untreated seeds (control). Minimum reduction percentages of root length (RPL root) and shoot length (RPL shoot) were attained from hydroprimed and haloprimed seeds due to NaCl and PEG conditions (-0.4 MPa), and maximum RPL root and RPL shoot were attained from controlled seeds due to NaCl and PEG (-1.2 MPa) conditions. The reduction percentage of dry weight for root (RPD root) and shoot (RPD shoot) increased according to increased osmotic potential in both NaCl and PEG, but RPD for shoot was significantly affected compared with RPD for root. Interaction of seed priming treatment and osmotic potential for the germination index (GI) showed that under 0 and - 0.4 MPa, hydroprimed and haloprimed seeds had higher GI as compared with untreated seeds due to NaCl and PEG conditions. Interaction between the seed priming treatment and osmotic potential significantly affected the vigour index (VI) due to NaCl and PEG conditions, and halopriming significantly increased VI at high osmotic potentials.
On average, the VI of haloprimed seeds was higher than that of untreated seeds at high osmotic potentials and was not significantly different from hydroprimed and untreated seeds at low osmotic potentials. It is concluded that under salinity stress, the osmotic effect is more important than the toxic effect in loss of seed germination. Moreover, hydropriming practically ensured rapid and uniform germination with few abnormal seedlings.
خلاصه ماشینی:
ir DESERT 19-1 (2014) 27-34 Halopriming and Hydropriming Treatments to Overcome Salt and Drought Stress at Germination Stage of Corn (Zea mays L.
Typical responses to priming are faster and closer spreads of time to germination, emergence over all seedbed environments, and wider temperature ranges of germination, leading to better crop stands, and hence improved yield and harvest quality, especially under suboptimal and stress growing conditions in the field (Parera and Cantliffe, 1994; Singh and Rao, 1993; Sadeghian and Yavari, 2004).
, 2006; Roy and Srivastava, 2000) have suggested that the adverse and depressive effects of salinity and water stress on germination can be alleviated by various seed priming treatments.
3. Results and Discussion The analysis of variance for the reduction percentages of germination (Tables 1 and 2), indicated a highly significant difference in interaction between seed priming treatments and osmotic potential in experiments with both NaCl and PEG (NaCl-induced salinity and PEG-induced drought).
In both seed priming treatments at different levels of osmotic potential, greater reductions in germination percentage were recorded for PEG than for NaCl (Fig. 1a, b).
Both seed treatments gave better performances than the control (untreated) under salt and drought stresses, clearly demonstrating the effectiveness of hydropriming in improving germination percentages at low water potential.
Interaction effects of seed priming treatment and osmotic potential significantly affected the vigour index (VI) due to NaCl and PEG conditions (Tables 1, 2), and hydropriming significantly increased VI at high (0, 0.