Histological characterization of banana (Musa spp.) genotypes submitted to water deficit
Banana (Musa spp.) is a key fruit crop planted in more than 130 countries. Due to changing climate, water availability presents a main bottleneck to crop production. The objective of this work was to characterize rhizome and leaf cuttings of two banana genotypes, previously selected for contrasting drought tolerance, during a water deficit imposition experiment. Sample cuttings from rhizomes and leaves of two genotypes, 'BRS Tropical' (AAAB genome, Silk type) and 'BRS-Prata AnãR' (AAB genome, Prata type), tolerant and susceptible genotypes, respectively, were compared. Eighteen plants from each genotype were used and nine submitted to water deficit for 18 days. The remaining nine plants were irrigated normally and maintained at normal field capacity. Rhizome and leaf samples were collected on the 1st, 10th and 18th day of water deficit. Significant differences were found between the rhizomes of 'BRS Prata Anã' and 'BRS Tropical', under water-stress conditions, and in contrast to their controls. Suberized cells were formed in the rhizome of 'BRS-Tropical', believed to therefore decrease water loss. In 'BRS-Prata Anã', suberization did not occur, and there was destruction of cortical parenchymal cells, which probably hindered development. Leaf cross-sections from the 'BRS-Tropical' cultivar statistically showed greater thickness for all variables evaluated in comparison with 'BRS-Prata Anã', except for hypodermal and adaxial thicknesses. Principal components analysis (PCA) separated 'BRS Tropical' according to the water regimes imposed and showed that although the first principle component (PC1) represented 96.59% of the available variability, leaf and mesophyll thickness are responsible for 34% of the variation observed. These findings will complement ongoing proteomics studies for these two contrasting banana genotypes. They confirm the morphological effects of water stress. Epidermal substitution by the periderm may be a specific morphological alteration conferring water-stress tolerance on 'BRS-Tropical'. Water stress seems to cause the destruction of cortical parenchymal cells in the susceptible cultivar 'BRS-Prata-Anã'.
Meira, C.F., Mattos-Moreira, L.A., Martins, F.M., Ledo, C.A.S., Amorim, E.P., Coelho Filho, M.A. and Ferreira, C.F. (2016). Histological characterization of banana (Musa spp.) genotypes submitted to water deficit. Acta Hortic. 1114, 133-138
drought tolerance, tissue cuttings