Changes of chloroplast ultrastructure and carbohydrate level in festuca, achillea and sedum during drought and after recovery.

The changes of chloroplast ultrastructure and carbohydrate level in C(4) sclerophyllous Festuca vaginata, C(3) malacophyllous Achillea ochroleuca and CAM succulent Sedum sexangulare were investigated during naturally induced drought and after subsequent recovery. Chloroplasts of the species show some characteristic changes due to drought: decreased volume, permanent adhesions within the grana, partitions become thinner, lipid droplets increase in number and size. Contraction of the stroma, swelling and blistering of thylakoids are characteristic of Sedum chloroplast and mesophyll chloroplasts of Festuca. Structure of bundle sheath chloroplasts of C(4) Festuca scarcely shows changes during drought and after recovery. During drought and subsequent recovery in the chloroplasts onf Achillea the slightest changes of the stromal and grana lamellae region can be observed. During drought starch grains are characteristic of chloroplasts of Achillea and Sedum; they disappear after recovery. Achillea and Sedum leaves contain more starch during drought than after recovery, while the starch content in Festuca is unchanged. There is more soluble sugar in Festuca and Sedum during drought than after recovery, although the amount of soluble sugar in Achillea is decreased during drought.