engleski

Structural and physiological characteristics of the coloured spots on the Leucojum perigone

The structure and physiological activity of coloured spots on the white perigone of Leucojum vernum were studied. The spots contained about 20 times less chlorophylls and about 2 times less carotenoids per fresh weight than the leaves. The greenish spots contained chloroplasts with a normally organized thylakoid system and the DAB reaction was positive thus confirming photosynthetic activity. The yellowish spots had a partially developed thylakoid system with single thylakoids occasionally stacking to form two overlapped thylakoid membranes. In some plastids specific complex aggregates of parallel membranes were also observed. Osmiophilic DAB deposits were present at most of the membranes of the single thylakoids, but at the membranes, arranged in aggregates, the DAB reaction was less intense. The photosynthetic activity of spot plastids was on the average 3 times lower than in the leaves but they they performed a very efficient photosynthesis. Although the spots probably have ecological significance, their photosynthetically active tissue also suggest a possible physiological role.

Leucojum vernum L.; perigone; plastids; ultrastructure; photosynthetic activity

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