MOSCOW, RUSSIA
Institute of Plant Physiology

Cross-tolerance to drought, salt and low temperature of maize plants regenerated from PEG-resistant cell lines
--Dolgykh, YI; Larina, SN and Shamina, ZB

Drought-tolerant plants have been regenerated from PEG-resistant callus lines of hybrids Chi31xCateto S.G. and Chi31xTuxpeno Norteno (MNL 69:105-106,1995). Their responses under salt and low temperature stresses were compared with the responses of the initial plants used for callus production.

Fifty kernels from each regenerant family were placed under moisture at 10 and 26 C. The relative rate of emergence of seedlings at 10 C was determined. The frequency of germination in all regenerant families exceeded the control value (Table 1). Seedlings after selection on PEG were also more tolerant to frost (-3 C for 2.5 h) than initial plants.

To determine the salt-tolerance, kernels of nine regenerated plants were germinated on 2% NaCl solution and then the seedlings were grown in soil with increasing concentrations of NaCl (0.5 to 1.2%). When the content of salt reached 1% all initial plants and plants of one regenerant family were lost. In other families 7.1 to 77.8% of plants stayed alive and could grow on 1.2% NaCl (Table 2). Part of the families were homogeneous: all seedlings demonstrated a similar level of viability and growth activity (fam. 90,91,98,121). In other families segregation took place: average viability was low but surviving plants grew on salty soil very well (fam.68).

Table 1. Emergence of the seedlings at 10 C.
 
Family number
Germination, %
Control 22.0
R 90 66.7
R 91 34.8
R 96 56.5
R 98 40.0
R 121 84.0

Table 2. Viability and growth rate of seedlings on 1.2% NaCl.
 
Family number Viability,% Fresh weight Dry weight(g /plant)
Control 0.0 - -
R 90 20.0 10.8 1.65
R 91(1) 38.9 11.9 1.60
R 91(2) 33.3 4.0 0.51
R 96 0.0 - -
R 98 77.8 13.3 1.63
R 119 76.5 11.2 1.60
R 121 11.8 5.1 0.49
Control 0.0 - -
R 68 9.1 22.2 2.42
R 83 7.1 10.5 1.20

These results show that the resistance of in vitro cultivated cells to osmoticum can be realised in the regenerated plants as tolerance to several environmental stresses. 


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