Instagram. The Plant Stand of Arizona Home Page. Flowers. Plant. Green plants have cell walls with cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts, derived from endosymbiosis with cyanobacteria.
Their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are also characterized by sexual reproduction, modular[clarification needed] and indeterminate growth, and an alternation of generations, although asexual reproduction is also common.
Precise numbers are difficult to determine, but as of 2010[update], there are thought to be 300–315 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants (see the table below). Green plants provide most of the world's molecular oxygen and are the basis of most of the earth's ecologies, especially on land.
NASA scientists are finding them to be surprisingly useful in absorbing potentially harmful gases and cleaning the air inside homes, indoor public spaces and office buildings. The indoor pollutants that affect health are formaldehyde, Volatile Organic Compounds (benzene and trichloroethylene or TCE), airborne biological pollutants, carbon monoxide and nitrogen oxides, pesticides and disinfectants (phenols), and radon. These pollutants contribute to ‘sick building syndrome’, which causes symptoms ranging from allergies, headaches and fatigue through to nervous-system disorders, cancer and death. Through studies conducted by NASA, scientists have identified 50 houseplants that remove many of the pollutants and gases mentioned above.
Plants Knowledge. Aqua + Plants.