Lyngbya major (a wall alga), survived throughout year, maximally to >80 % at atmospheric temperature (AT) of 17-36 degrees C and relative humidity (RH) 60-100 % in rainy and spring seasons, but the survival was 43-64 % in winter when AT decreased to 5 degrees C and RH was 65-98 %, and 15-23 % in summer when AT reached 48 degrees C and RH was 23-60 %. All soil algae (Lyngbya birgei, Aphanothece pallida, Gloeocapsa atrata, Oscillatoria subbrevis, O. animalis) survived >90 % in rainy season when soil moisture content (SMC) was 89-100 %. Lowering of SMC to a minimum of 55 % in spring and 39 % in winter led L. birgei, O. subbrevis and O. animalis to survive from 75, 66, and 65 %, respectively, in spring and 12, 14, and 20 % in winter, and A. pallida and G. atrata not at all in both seasons. All soil algae did not survive in summer when SMC was 12-30 %. Myxosarcina burmensis survived only in rainy and spring seasons when pond water temperature (PWT) was 19-25 degrees C and 18-26 degrees C, respectively, and not in winter and summer when PWT was 2-14 degrees C and 25-36 degrees C, respectively. L. major and A. pallida survived almost equally well under both submerged and air-exposed conditions for 15 d but less if submerged for more time than air-exposed on moist soil surface, while L. birgei, G. atrata, O. subbrevis, and O. animalis survived submergence in liquid medium better and longer than air-exposure on moist soil surface. Pond alga M. burmensis survived submergence better than air-exposure, true to its aquatic habitat. All algae survived less and died without forming any resistant cells when exposed to physical and physiological water stress (imposed by growing them on highly agarized media or in salinized liquid media), light stress (at 0, 2 and 10 micromol m(-2) s(-1) light intensity) or following UV shock (0.96-3.84 kJ/m(2)). A. pallida and G. atrata cells did not divide on 8 % agarized solid media, in > or =0.3 mol/L salinized liquid media, and in darkness. The presence of sheath over L. major and L. birgei filament cells and mucilage cover over A. pallida and G. atrata cells protect them against physical desiccation to some extent but not against UV shock.
Pithophora oedogonia and Cladophora glomerata survived lowest 60 and 58%, respectively, in June when the pond diurnal water temperature (PDWT) increased to a maximum of 28 degrees C. The lowering of PDWT only by 1 degrees C in July improved survivability of both algae to their almost maximum level of 100 and 96%, respectively. Further lowering of PDWT to 17-22 degrees C in November initiated akinete formation in P. oedogonia. The process of akinete initiation, maturation and germination continued till April when PDWT increased to 20-24 degrees C, but not beyond that in May when PDWT was 21-26 degrees C. By this time, probably all akinetes have germinated in situ, and the alga was entirely vegetative. P. oedogonia population is not synchronous in nature, since during the 5-6-month reproductive season, some filaments were in active vegetative stage, some had akinete initiation, some had completed akinete formation, and some had akinetes germinating. C. glomerata grew dense vegetative in November and initiated (zoo)sporangial primordia formation (to some extent) in February (when PDWT was lowest, viz. 10-14 degrees C) till April. Meanwhile, no (zoo)-sporangial primordia either produced any zoospore or germinated into a germ tube; and all released their cytoplasmic content and died (along with some vegetative cells) with an increase in PDWT to 21-26 degrees C in May. Vaucheria geminata vegetative patches appeared on the soil surface, 2nd week of January by lowering of atmospheric diurnal temperature (ADT) to 9-16 degrees C in the 1st week. The alga started sexual reproduction by the 2nd week of March (when ADT increased to 20-23 degrees C) and completed the process of reproduction by the 1st week of April (when ADT increased to 24-26 degrees C) and died thereafter. P. oedogonia, C. glomerata and V. geminata survived better and longer in submerged conditions than air-exposed (which was true for P. oedogonia and C. glomerata aquatic habitat and also indicated that the soil alga V. geminata could survive to some extent if submerged in rain water). P. oedogonia formed akinetes and C. glomerata (zoo)sporangial primordia only in submerged condition and not when air-exposed on moist soil surface. V. geminata did not complete the life cycle both under submerged and air-exposed conditions. Vegetative survival in P. oedogonia, C. glomerata, V. geminata, Aphanothece pallida, Gloeocapsa atrata, Scytonema millei, Myxosarcina burmensis, Phormidium bohneri, Oscillatoria animalis, O. subbrevis, Lyngbya birgei, L. major, Microcoleus chthonoplastes and Rhizoclonium crassipellitum, reproduction in P. oedogonia, C. glomerata and V. geminata, cell division in A. pallida and G. atrata, heterocyst and false branch formation in S. millei, all, were adversely affected at approximately 28.5 degrees C for t12 h at light intensity of approximately 160 micromol m(-2) s(-1); high intensity does not ameliorate high temperature damage to any algae. The presence of liquid water, than its absence, outside the different algae moderated the severity of heat to some extent but not when the heat was severe.
Navicula grimmei and Nitzschia palea occurring almost equally in a mixed population on department moist garden soil surface when maintained in fresh supernatant (of soil-water medium) at pH 7.0, temperature of 26 +/- 1 degree C and under continuous light (intensity of approximately equal to 30 micromol m(-2) s(-1)) in a culture chamber exhibited a similar cell survival period (of 28 d) and percentage (at the beginning 100 % and mid of survival period 65 %) and stop gliding 11 d prior to cell death (with gliding speed reduced in both from 204-330 microm/min at the beginning to 82.5-99 microm/min at the mid of gliding period) irrespective of their size differences. However, a sharp fall in the cell gliding period, gliding cell percentage and speed occurred at various levels (different from cell survival period and percentage) in both diatoms in a similar extent under water stress (2, 4 and 6 % agarized supernatant, liquid supernatant with 0.2-1.0 mol/L NaCl, blot-dryness of cells for 5-15 min), pH extreme of liquid supernatant (< or =5.0, > or =9.0), temperature extremes in liquid supernatant (< or =15, > or =40 degrees C), UV exposure (0.96-5.76 kJ/m2), lack of all nutrients from the medium (double distilled water), darkness or low light intensities (2 and 10 micromol m(-2) s(-1)), presence of 'heavy' metals (Ni, Cu, Zn, Co, Fe, Hg; 1-200 ppm), organic substances in liquid supernatant (DDT, captan, urea, 2,4-D, 100-2000 ppm; thiourea, 50-1000 ppm). N. palea sway (turn around at either ends) or not only when gliding but independent of cell gliding speed, which decreased continuously under all conditions.
- MeSH
- Eukaryota cytologie klasifikace růst a vývoj MeSH
- močovina chemie škodlivé účinky MeSH
- organické látky chemie škodlivé účinky MeSH
- pohyb buněk fyziologie účinky léků MeSH
- rozsivky fyziologie chemie růst a vývoj MeSH
- těžké kovy chemie škodlivé účinky MeSH
- thiomočovina chemie škodlivé účinky MeSH
- ultrafialové záření škodlivé účinky MeSH
- viabilita buněk fyziologie účinky léků MeSH
