Effect of temperature regime on growth and subsequent responses of Sophora japonica seedlings to SO₂

Ten-week-old Sophora japonica seedlings were grown for 10 weeks at 17, 22, or 27°C and then exposed to 0 or 1.0 μℓ/SO₂ for 48 hours. The seedlings were subsequently grown at 22°C and harvested 12 weeks later. Effects of preconditioning temperature and SO₂ on leaf formation, seedling height and stem diameter, as well as dry weight increment and relative growth rates of leaves, stems, and roots were studied. The preconditioning temperature regime influenced growth and subsequently affected SO₂ uptake and growth. However, the responses of seedlings to temperature and SO₂ varied with the growth parameter measured. The need for greater standardization of methods and criteria for assessing pollution tolerance of plants is emphasized.