Біологічні студії (Sep 2016)

Structural-functional peculiarities of water fern Salvinia natans (L.) All.

  • L. M. Babenko,
  • M. M. Shcherbatiuk,
  • O. V. Polishchuk,
  • I. V. Kosakivska

DOI
https://doi.org/10.30970/sbi.1002.476
Journal volume & issue
Vol. 10, no. 2
pp. 149 – 162

Abstract

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The characteristics of photosynthetic pigments and efficient use of light energy are analyzed fon the example of chloroplast ultrastructure of the photosynthetic apparatus of floating and submerged fronds of annual heterosporous of water fern Salvinia natans (L.) All. in ontogenesis. It is established that at the stage of intensive growth chloroplasts floating fronds had a well-developed system of thylakoid membranes with many faces and contain a lot of starch grains. Submerged fronds shaped chloroplasts are smaller with little starch in the stroma. Destructive changes in chloroplast photosynthetic membranes of both frond types are observed at the stage of sporocarp formation. Particularly, decomposition of gran tylakoiod membranes, disturbances in inter-gran connections, reduction of starch grain number in stroma were revealed. In the chloroplast stroma of floating wai numerous plastoglobules were fouond. In chloroplasts submerged fronds fewer plastoglobules education were noted. In addition, a certain portion of popu­lation hloroplastoa in both types fronds retains intact structures.The photosynthetic pigment content of floating fronds was found to exceed that of submerged two times, and at some stages of ontogenesis – three times. At the stage of sporocarp formation, the chloroplast and carotinoid content in fronds of the both types decreased. Floating fronds are characterized by an effective action of the chloroplast photosynthetic electron transport chain, and are adapted to an intensive natural lighting on a water surface. Submerged fronds affected by lighting whose intensity fits with a maximum level of natural characteristics were found to be at stress. That was confirmed by a decrease in quantum efficiency ФСІІ (ΦPSII) and increase in dissipation of excessive light energy as heat in rise of the level of nonphotochemical quenching of chloroplast fluorescence (NPQ).

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