Leaf characterization of Spermacoce verticillata at three stages of development

Abstract

Weed control is an essential practice in crop management. However, the use of herbicides may not be effective in certain situations, such as when problems are encountered in the application technology and when tolerant individuals and resistant biotypes are observed. In the cotton producing areas of the state of Bahia, Brazil, Spermacoce verticillata (shrubby false buttonweed) is not effectively controlled during burndown applications. During different developmental stages, plants can modify their leaves’ anatomical structures, which may influence herbicide control by modifying the retention, absorption, translocation and final effect of the chemical. This study assessed the morphological and histological differences in Spermacoce verticillata leaves at different stages of development. Leaves were collected from plants at different phenological stages (2-4 leaves, 4-6 leaves and flowering) and subjected to histological and scanning electron microscopy analyses. In the histological analysis, four leaves were collected from the upper nodes. The evaluated characteristics were the total leaf blade thickness, palisade and spongy parenchymal thicknesses, cuticle and epidermal cell thicknesses on the abaxial and adaxial surfaces and midrib height and width. Surface analyses were performed by observing the leaves under a scanning electron microscope. As the developmental stages of Spermacoce verticillata advanced, the plants began to show reduced leaf thickness due to the decreased abaxial epidermal thickness, transport vessel size and parenchymal thickness. At more advanced stages of development (4-6 leaves and flowering), the adaxial leaf surfaces showed fewer stomata and more trichomes.

Nontarget‐site resistance due to rapid physiological response in 2,4‐D resistant Conyza sumatrensis: reduced 2,4‐D translocation and auxin‐induced gene expression

“…1(a)] could be a result of differences in the biotype's characteristics, such as differences in leaf cuticle or self-limiting effects of the rapid response cell death. 35 Most applied herbicide did not translocate [Fig. 1 3) and roots (7.04% ± 0.58) [Fig.…”

Eficiência de Glyphosate no controle de Spermacoce verticillata L. em diferentes estágios de desenvolvimento

“…Dentre as espécies de plantas daninhas que apresentam grande potencial de causar prejuízos às pastagens destaca-se Spermacoce verticillata L., conhecida regionalmente como vassourinha-de-botão. Essa espécie é reconhecida por sua rusticidade e facilidade de adaptação a solos ácidos e pobres em nutrientes como os da Amazônia (FADIN; MONQUERO, 2019). Além disso, S. verticillata produz grande quantidade de propágulos muito pequenos que germinam em abundância após sua dispersão.…”