Change of Osmotica in Oat Leaf under Soil Moisture Stress

Impacts of soil moisture availability on osmotica in leaves of oat at different soil moisture stress levels were investigated using a cultivar-Neinongda No.1 grown in pots under rain-proof shelter.In the experiments,proline and soluble sugar contents in leaves and relative permeability of cell membrane of leaves at different development stages were determined.Proline and soluble sugar contents and relative permeability of cell membrane of leaves at all stages increased with the decline of soil moisture.Proline contents in leaves under 30% and 45% soil moisture treatments increased with the growth of oat,but those under 60%,75% and 90% soil moisture treatments rose until filling stage and then decreased.Soluble sugar contents during the whole growth stage presented a parabolic curve,with maximums occurring at earlier stages when moisture stress intensified,e.g.,at elongation stage under 30% and 45% soil moisture treatments,but at booting and flowering stages under 60% and 75% soil moisture treatments,respectively.Relatively permeability of cell membrane increased with the growth of oat.Therefore,soil moisture stress stimulated osmotica accumulation in oat leaves,more osmotica accumulated under heavier moisture stress.