Anatomical adaptations to different soil moisture contents in palisade grass and smooth pigweed

Abstract

Weed adaptations to different environments contribute to their success in establishing in different agroecosystems. A greenhouse and laboratory study was carried out to evaluate the effects of different levels of soil moisture on the anatomical characteristics of two weed species. The treatments were arranged in a 2 x 5 factorial design, with the first factor representing the weed species (Amaranthus hybridus and Brachiaria brizantha) and the second factor being the soil moisture levels in which they were grown (100%, 80%, 74%, 67%, and 60% of field capacity). At 55 days after weed emergence, the material for anatomical evaluations was collected. The water stress affected the two weed species differently, causing changes both in the thickness of the tissues evaluated and in their proportions. These changes seem to be related to how each species tolerates water stress. A. hybridus showed thickening of all leaf tissue and change in the proportion of these tissues, whereas B. brizantha showed a decrease in thickness of the leaf tissue and an increase in the proportion of adaxial epidermal and parenchymal tissues.

Morphoanatomic characterization of Gomphrena perennis and Gomphrena pulchella leaves

“…All values of MT were lower than those of G. arborescens (384.40 µm) (Carvalho et al, 2005). MT values of Gpe at S1 (230.97 μm) and S2 (208.72 μm) were higher than those determined by Silva et al (2018) in A. hybridus (160 µm). Gpu had lower values than Gpe at all stages (Table 4 and Figure 2b).…”

Morphoanatomic characterization of Gomphrena perennis and Gomphrena pulchella leaves

“…For each variable and phenological stages, means followed by different letters, differ by the t-test at p≤0.05 μm) µm)(Carvalho et al, 2005). MT values of Gpe at S1 (230.97 μm) and S2 (208.72 μm) were higher than those determined bySilva et al (2018) in A. hybridus (160 µm). Gpu had lower values than Gpe at all stages (Table…”

“…However, Gpe at S1 and S2 was above this range. Both, Gpe and Gpu showed higher thickness than other weed species of the family, such as Amaranthus deflexus (149.50 μm), A. spinosus (264.34 μm), Alternanthera tenella (252.39 μm) (Ferreira et al, 2003), Amaranthus hybridus (220 μm) (Silva et al, 2018), and weeds of other families (Ferreira et al, 2002a;2002b). Upper and Lower Epidermis thickness values in general were similar in the two species studied, as it was observed in A. spinosus.…”