<Tr> <Td_colspan="2"> <P> Arabis thaliana </P> </Td> </Tr> <P> Arabidopsis thaliana, the thale cress, mouse - ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa . A. thaliana is considered a weed; it is found by roadsides and in disturbed land . </P> <P> A winter annual with a relatively short life cycle, A. thaliana is a popular model organism in plant biology and genetics . For a complex multicellular eukaryote, A. thaliana has a relatively small genome of approximately 135 megabase pairs (Mbp). It was the first plant to have its genome sequenced, and is a popular tool for understanding the molecular biology of many plant traits, including flower development and light sensing . </P> <P> Arabidopsis thaliana is an annual (rarely biennial) plant, usually growing to 20--25 cm tall . The leaves form a rosette at the base of the plant, with a few leaves also on the flowering stem . The basal leaves are green to slightly purplish in color, 1.5--5 cm long and 2--10 mm broad, with an entire to coarsely serrated margin; the stem leaves are smaller and unstalked, usually with an entire margin . Leaves are covered with small, unicellular hairs (called trichomes). The flowers are 3 mm in diameter, arranged in a corymb; their structure is that of the typical Brassicaceae . The fruit is a siliqua 5--20 mm long, containing 20--30 seeds . Roots are simple in structure, with a single primary root that grows vertically downward, later producing smaller lateral roots . These roots form interactions with rhizosphere bacteria such as Bacillus megaterium . </P>

Why is arabidopsis thaliana a good research tool