There were carried out two glasshouse experiments which investigated a reaction of two white clover cultivars (‘Dara’, ‘Rawo’) to water stress. In the first experiment the pots were filled with mineral soil, while in the second one – with organic soil. The mineral soil moisture was maintained at the level of 35 and 70% of the field water capacity, while that of organic soil – at the level of 40 and 80% of the field water capacity. Over vegetation the intensity of photosynthesis was measured with the apparatus measuring gas exchange Li-Cor 6400 and leaf greenness index with chlorophyll meter SPAD-502. The plants were cut three times. The biomass obtained was investigated with chemical analyses. The results showed that water stress significantly limited the intensity of photosynthesis and plant yielding as well as increased the content of chlorophyll in white clover leaves. Out of the two cultivars tested, a greater photosynthesis capacity was recorded in ‘Dara’, while ‘Rawo’ leaves were richer in chlorophyll. A significant positive correlation was noted between the intensity of photosynthesis and dry matter yield and a negative correlation between the SPAD leaf greenness index and the intensity of photosynthesis. The type of soil on which white clover was grown affected the intensity of photosynthesis, yielding and chemical composition of plants, however it did not affect the content of chlorophyll expressed as the SPAD leaf greenness index.

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