Conventional soil and hydroponic growing systems have inherent differences in water and nutritional availability. These differences may affect plant physiological development and biochemistry. The objective of this study was to evaluate lettuce (Lactica sativa) cv. ‘Crocantela’development in either a hydroponic system or in soil through analyses of vegetative growth; chlorophyll abundance; and sugar and starch content. We evaluated the dry mass (DM), fresh mass (FM), number of leaves (LN), stomatal density and contents of chlorophyll, carotenoids, sugars and starch. Due to the improved nutritional conditions, especially in relation to macronutrients, plants grown in hydroponic system presented significant differences in chlorophyll a (0.4481 mg/g), b (0.1233 mg/g) and total chlorophyll content (0.5714 mg/g), as well as greater biomass when compared to plants cultivated in pots (FM: 342.69 g; DM: 21.13 g; NL: 17.75 g). The lower water availability for plants cultivated in pots influenced the increase in carbohydrate concentration and stomatal density in leaves (adaxial: 45.83 stomates/mm2; abaxial: 64.75 stomates/mm2) of lettuce plants.

Although karyotype features are useful data for evolutionary studies, cytogenetic data in Bambusoideae are mainly based only on chromosome counts. The first comparative cytogenetic analysis of three Neotropical woody bamboo species -Guadua chacoensis, G. angustifolia and Chusquea tenella -was undertaken based on new and reviewed chromosome counts, CMA/DAPI double staining, fluorescent in situ hybridization (FISH) with 35S and 5S rDNA probes, and genome size estimation. The two species of Guadua were found to have 2n = 46 chromosomes, while the first record for C. tenella was 2n = 44. Only one pair of CMA + /DAPIwas detected on the terminal region of metacentric chromosomes in all three species. Likewise, one pair of 5S and 35S rDNA sites was detected in all three species, with the 35S rDNA sites always collocated with the CMA + bands. Genome sizes ranged from 2C ≈ 3.99 pg for the species of Guadua, to 2C = 4.77 pg for C. tenella. Considering the Miocene origin of Neotropical woody bamboos, the observed karyotype stability suggests that the analyzed species are diploidized paleopolyploids. The results reveal the conservative cytomolecular organization of Neotropical woody bamboo karyotypes, which helps to improve our understanding of the evolution of this group.

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