Changes in the chlorophyll and carotenoid contents in the leaves of steppe plants along a latitudinal gradient in South Ural

We studied the content of chlorophylls and carotenoids in the leaves of steppe plants of South Ural growing along a latitudinal gradient from southern steppe to forest-steppe. The content of chlorophylls (a + b) was 5–6 mg per 1 g of the leaf dry weight and did not depend on the latitude, whereas the content of carotenoids in the leaves increased northward from 1.0 to 1.5 mg/g dry wt. At the same time, the greatest changes occurred in the ratios between the forms of pigments: the chlorophyll a/b ratio increased from 1.8 to 2.8, and the chlorophyll/carotenoid ratio decreased from 5.6 to 3.5. The obtained results indicate that adaptation of the pigment apparatus of steppe plants growing along the latitudinal gradient occurs due to the transformation of the light-harvesting complex.