Abstract

BARRIOS-GOMEZ, Edwin Javier et al. Comparison of morphological structures in bean root and hypocotyl. Rev. Mex. Cienc. Agríc [online]. 2012, vol.3, n.4, pp.655-669. ISSN 2007-0934.

In 2006 an experiment was conducted with the aim to determining the differences in development of contrasting varieties of bean (Phaseolus vulgaris L.) root and shoot of the seedling. As known, drought-tolerant cultivars have xylem vessels of the root and hypocotyl of smaller diameter than the cultivars susceptible to drought, using five contrasting beans, of indeterminate habit type III, from which seedlings were harvested at 7, 11, 15, 19 and 23 days after sowing (DAS); moreover, in the latest seedling harvest (23 DAS), root samples approximately 1 cm in length were taken. The cuts in the main root were made at three positions; in the nodal región, 1 cm below the hypocotyl-root axis, in the middle and, 1 cm from the apex of each variety. The drought-tolerant cultivar (FM Corregidora) had roots and xylem vessels of smaller diameter than the drought-susceptible cultivar (FM CMR) and low performance landrace (Michoacán 128). FM Corregidora showed greater length and total dry weight of the roots than FM CMR and Michoacán 128. FM Corregidora's roots grow faster than the other cultivars', giving a greater development in the seedling stage. The diameter of the hypocotyl and the central hole is greater in FM Corregidora and, the high-yielding cultivars (FJ Marcela and FM Bajío) than in the susceptible to drought and the landrace. FM Corregidora, FJ Marcela, FM Bajío and FM RMC have a thicker crust and a higher number of xylem vessels than Michoacán 128. Drought-tolerant material (FM Corregidora) showed roots and xylem vessels of smaller diameter than the drought-susceptible cultivar's (FM CMR) and low-yielding landrace's (Michoacán 128).

Keywords : Phaseolus vulgaris L.; root development; root and hypocotyl morphology; vascular transport.