Abstract
Background
Gomphrena perennis (Gpe) and G. pulchella (Gpu) are perennial glyphosate-tolerant amaranthaceous weeds of central and northern Argentina where glyphosate-resistant soybeans are grown with no-till. The study of weeds leaves morphoanatomy is important to understand environmental adaptation and could be used to explain herbicide absorption. Leaf surfaces of Gomphrena species were previously described for phylogenetic studies, and morphoanatomy of two Gomphrena perennis populations was characterized for glyphosate tolerance. There are no reports on comparative studies of Gpe and Gpu. We hypothesize that these two species differ in their morpho anatomical characteristics.
Objective
The aim of this research was to characterize and compare their leaf morphoanatomy throughout their life cycle.
Methods
Fully developed leaves of the upper middle third were extracted from plants grown in pots in a greenhouse at three phenological stages: eight true leaves (S1), beginning of branching (S2), and full flowering (S3). In both leaf sides, densities of epidermal cells, stomata and trichomes, and ostiole lengths were quantified. In main and secondary bundle anatomic parameters were measured: thickness of total blade, upper and lower epidermis, and mesophyll, and sheath length.
Results
Both species are amphiestomatic. Gpu had higher stomata densities in lower epidermis than Gpe at S1. Gpu had higher trichome densities than Gpe, whereas the latter presented higher values in anatomic variables mainly in secondary bundle (total blade and total mesophyll) at all stages.
Conclusions
There were no marked differences in the morphoanatomy between the two species throughout their life cycle.
Lámina total; Epidermis; Mesófilo; Estomas; Tricomas
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