This review surveys on the influence of different environmental factors like light (intensity, quality, photoperiod), temperature, season, nutrients (inorganic, organic), biotic factors (algal extracellular products, bacterial association, animals grazing), osmotic stress, pH of the medium, wave motion and mechanical shock, pollution, and radiations (UV, X-rays, gamma radiation) on the induction (or inhibition) of algal reproduction like cell division in unicellular algae, and formation of zoospores, aplanospores, akinetes, cysts, antheridia, oogonia, zygospores, etc.

• MeSH
• Ecosystem * MeSH
• Eukaryota growth & development   physiology   MeSH
• Plant Physiological Phenomena * MeSH
• Reproduction * MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.

• MeSH
• Algal Proteins metabolism   MeSH
• Cell Membrane enzymology   MeSH
• Chlorella physiology   radiation effects   MeSH
• Enzymes metabolism   MeSH
• Nitric Oxide physiology   MeSH
• Second Messenger Systems * MeSH
• Ultraviolet Rays * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Algal Proteins MeSH
• Enzymes MeSH
• Nitric Oxide MeSH

This review surveys whatever little is known on the influence of different environmental factors like light, temperature, nutrients, chemicals (such as plant hormones, vitamins, etc.), pH of the medium, biotic factors (such as algal extracellular substances, algal concentration, bacterial extracellular products, animal grazing and animal extracellular products), water movement, water stress, antibiotics, UV light, X-rays, gamma-rays, and pollution on the spore germination in algae. The work done on the dormancy of algal spores and on the role of vegetative cells in tolerating environmental stress is also incorporated.

• MeSH
• Ecosystem * MeSH
• Eukaryota physiology   radiation effects   MeSH
• Spores physiology   radiation effects   MeSH
• Cell Survival MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Fourteen blue-green and green algae survived for widely different time periods ranging between 22-102 d in control culture medium. Irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different morphological types or natural habitats, they all survived for a short time period ranging between 3-8 d in sewage water, 5-10 d in fertilizer factory effluent, (1/4)-2 d in brassica oil, (1/2)-2 d in phenol, 1-3 d in toluene, and 1-4 d in benzene (showing the relative toxicity of different chemicals to different algae, and the antialgal nature of brassica oil). Dilution decreased the toxicity of these agents very little, indicating that they all were very toxic to algae. None of the agent induced the formation of any reproductive or dormant cells. Sewage water, fertilizer factory effluent, brassica oil and/or benzene favored the formation of necridia cells in Phormidium bohneri, P. foveolarum, Microcoleus chthonoplastes, Lyngbya birgei, and L. major filaments. Scenedesmus quadricauda shed off all spines earlier, Hormidium flaccidum fragmented less or not at all, Scytonema millei formed no false branch and heterocyst, Aphanothece pallida and Gloeocapsa atrata cells did not divide, Cosmarium granatum cells did not form any zygospore and Oedogonium sp. not any oogonia-like cells under all or most of treatments with 25-100 % sewage water, 1-100 % fertilizer factory effluent, 1-100 % brassica oil, 25-100 % phenol, toluene and benzene.

• MeSH
• Benzene pharmacology   MeSH
• Water Pollutants, Chemical pharmacology   MeSH
• Chlorophyta drug effects   physiology   MeSH
• Phenol pharmacology   MeSH
• Sewage analysis   MeSH
• Organic Chemicals pharmacology   MeSH
• Industrial Waste analysis   MeSH
• Reproduction drug effects   MeSH
• Spores drug effects   physiology   MeSH
• Toluene pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Benzene MeSH
• Water Pollutants, Chemical MeSH
• Phenol MeSH
• Sewage MeSH
• Organic Chemicals MeSH
• Industrial Waste MeSH
• Toluene MeSH