Please confirm you are human (Sign Up for free to never see this)
← Back to Search
Effects Of Boron On Leaf Expansion And Intercellular Airspaces In Mung Bean In Solution Culture
Published 2005 · Biology
ABSTRACT Mung bean (Phaseolus aureus Roxb.) was grown in solution culture to study the effect of boron (B) deficiency on leaf expansion and intercellular airspaces. Different B concentrations were supplied just after initiation of the second trifoliate leaf because this is the first leaf whose growth depends on the exogenous B supply. The central leaflet of the second trifoliate was employed in this study. When plants were grown in 0.2 μ mol L−1 B, leaf expansion was limited compared with that of plants supplied with 50 μmol L−1 B. During the progress of leaf development, plants grown in 0.2 μ mol L−1 B were transferred to medium with 50 μ mol L−1 B medium at days 2, 4, 6, and 8. The final leaf area of plants transferred on day 2 was half that of plants raised in 50 μ mol L−1 B solution. Plants transferred on days 6 and 8 produced a leaf area similar to that of plants grown in 0.2 μ mol L−1 B. Uptake experiments with 10B-enriched boric acid showed that there was enough B present at the sites of cell expansion after 50 μ mol L−1 B was supplied for two days. The failure of deficient leaves to resume elongation may therefore have been due either to a lack of incorporation of B into the cell wall or boron or to a requirement for B early in leaf development to enable future cell wall expansion. In addition to the reduced leaf expansion resulting from B deficiency, the formation of intercellular airspaces was also depressed. The proportion of the spongy mesophyll region comprising airspaces in B-deficient leaves was less than 50% of that observed in leaves of plants supplied with sufficient B.