The utilization of leaf wax by N₂-fixing micro-organisms on the leaf surface

Abstract

SUMMARYThe possibility of utilization of leaf wax by N2-fixing micro-organisms on the leaf surface of plants was examined. Chloroform and n-hexane extractable wax could be isolated in significant amounts, ranging between 0·13 and 6·83 g/kg fresh weight from leaves of rice cv. IR·26, wheat cv. Sonalika, jute cv. JRO 632, pigeon pea, Ficus benghalensis, F. religiosa, Eichornia crassipes, Calotropis procera and Cocos nucifera. Pigeon pea and coconut leaves were very rich in wax. The utilization of leaf wax was studied by observing the growth of micro-organisms in Burk's N-less DN2 medium containing 0·025% yeast extract and jute or coconut leaf wax as the sole C source. A 2·fold increase in growth was observed as compared with the control containing no wax. The most growth was exhibited by Pseudomonas azotogensis, P8. azotocolligans, Xanthobacter flavus, Azotobacter paspali 23A and Klebsiella pneumoniae Kupbr2. Utilization of wax components was studied by comparing the amounts of acetylated alcohols and methyl esters of fatty acids in leaves inoculated with those untreated with bacteria after separation of the components by gas chromatography. A strain of K. pneumoniae KUP4, the association of which very remarkably improved the growth of jute plants, was found to utilize particularly C10–, C13– and C16– saturatedfatty acids and C15–, C18–, C25–, C26– and C27– fatty alcohols. It is suggested that leaf wax may act partly as an energy substrate for growth of N2-fixing micro-organisms on the leaf surface.

Bactérias diazotróficas associadas a coqueiros na região de baixada litorânea em Sergipe

“…Além disso, a filosfera de coqueiro tem sido sugerida como um habitat apropriado para o crescimento de diazotróficas capazes de utilizar as ceras das folhas desta planta como fonte de carbono. Entre as diazotróficas com esta capacidade, são relatadas duas espécies: Pseudomonas azotogensis e P. azotocolligans (Samanta et al, 1986).…”

Wax Degrading Bacteria: Scope and Applications in Agriculture

“…P2(1) utilizing hydrocarbon from petroleum contaminated soil and Kumar et al, (2015) isolated biosurfactants producing bacterial isolates characterized as Pseudomonas plecoglossicida, Lysinibacillus fusiformis and Bacillus safensis from oil contaminated soils. Samanta et al, (1986) reported heterotrophic nitrogen fixing bacteria Pseudomonas azotogensis, Xanthobacter flavus, Azotobacter paspali and Klebsiella pneumonia capable of utilizing jute leaf wax. Secondly, the emphasis is on water repellency: water repellency is a widespread phenomenon that occurs naturally due to accumulation of hydrophobic waxes or humic substances on soil particles.…”

“…But few microbes that grow using hydrocarbons showed the ability to accumulate the substrate intracellularly as inclusion bodies. The uptake of the solid n-alkanes by microorganisms occurred through transport across the cell membrane (Samanta et al, 1986). Adherence is an important phenomenon for hydrocarbon utilization by microorganisms.…”