[The modern concepts on the primary cell walls of angiosperm plants]. / Sovremennye predstavleniia o pervichnykh kletochnykh stenkakh pokrytosemennykh rastenii.

The modern view on polysaccharide composition of the primary cell wall of angiosperm plants was considered, and five classes of structural proteins were characterized. The model which shows location of enzyme complex synthesizing cellulose, as well as structural model of primary cell walls of the most flowering plants were presented. Besides, there were shown cell wall reactions to environmental factors which have contradictory character and have to be deeply and thoroughly analyzed.

Calcium balance in pea root statocytes under both clinorotation and Ca2+ channel blockers' influence.

We have previously demonstrated that space flight and clinorotation conditions increase cytoplasmic Ca2+ level in pea root statocytes. A rise in [Ca2+]i may be a serious problem for plants in microgravity environment. It is hypothesized that involvement of Ca2+ channel blockers in the growth medium may rescue a plant from abundance of Ca2+ ions. Indeed, combination of clinorotation (2 rpm, 5 days) and any Ca2+ channel blocker (1 micromole D600 or nicardipine, 12 hr) causes decreasing the Ca2+ concentration in pea root statocytes in comparison with clinorotation alone. Redistribution of Ca(2+)-ATPase activities observed under clinorotation comes to normal after D600 application whereas following by nicardipine action the pattern of the cytochemical staining is intermediate between those in stationary control and under clinorotation. Our data support the hypothesis that Ca2+ channel blockers may act as protectors for plants against rise in [Ca2+]i. The role for Ca2+ channels in graviperception and in microgravity effects as well as ways for stabilization of Ca2+ balance in plant cells in space flights are discussed.