The first anatomical and histochemical study of tough lovegrass (Eragrostis plana Nees, Poaceae)

Abstract

Eragrostis plana Nees (Poaceae), known commonly as tough lovegrass, is the most abundant invasive plant found in the rangelands of Southern Brazil. This study is the first to document the anatomical and histochemical features of the leaves and roots of this grass. Five leaf blades and five roots were collected, fixed in formaldehyde, glacial acetic acid, ethanol 70° (FAA 70), sectioned, stained, and photographed under a light microscope. Anatomical analysis of the leaves was supplemented with observations under a scanning electron microscope. Manual cuts were made into fresh material, which was subjected to specific reagents to determine the lipid, phenol, tannin, lignin, alkaloid, and starch presence. The analyses revealed that the leaves are amphistomatic with paracytic stomata, and the epidermis has lignified cells, a Kranz structure, collateral vascular bundles of two sizes, tectors, unicellular and crystalline trichomes. The roots are polyarc with air gaps on the cortical parenchyma, Uthickened endodermal cell walls and a parenchymatic pith with starch storage cells. Leaves and roots contain lipids, phenols, lignins, and alkaloids; starch is only present in the roots. Anatomical and histochemical traits of tough lovegrass suggest that the plant has adapted to survive under biotic and abiotic stress, which enhances its performance in relation to native plants.

Using Leaf Temperature to Improve Simulation of Heat and Drought Stresses in a Biophysical Model

“…To run the simulations, climate files required for DairyMod were prepared using the data recorded in each growth chamber including light intensity (µmol m −2 s −1 ), Leaf temperatures calculated using leaf energy budget equation were in good agreement with measured values for grasses but, the equation did not work well for chicory. Chicory, being a dicot plant has stomata only in one side of the leaf (hypostomatic dicot) and in contrast, grasses possess stomata on both sides (amphistomatic monocots) [43]. Grasses show greater conductance for vapor than chicory because conductance occurs from both sides of the leaves in grasses.…”

Biology of the invasive species Eragrostis plana in Southern Brazil: What have we learned and how may this help us manage it?

“…C4 plants are highly productive at high temperatures and low relative humidity. Eragrostis plana leaves are amphistomatic with paracytic stomata (Favaretto, Santos, et al, 2015). Cell wall thickening and lignification in the genus Eragrostis results in high tensile strength and greater tolerance to drought and mechanical damage (Balsamo et al, 2006).…”

“…Cell wall thickening and lignification in the genus Eragrostis results in high tensile strength and greater tolerance to drought and mechanical damage (Balsamo et al, 2006). Leaves have a Kranz structure (Figure 5A) and two sizes of collateral vascular bundles (Favaretto, Santos, et al, 2015). Roots have a parenchymatic pith with starch storage cells (Favaretto, Santos, et al, 2015), and aerenchym extension (Caratti, 2019; Favaretto, Santos, et al, 2015).…”

“…Leaves have a Kranz structure (Figure 5A) and two sizes of collateral vascular bundles (Favaretto, Santos, et al, 2015). Roots have a parenchymatic pith with starch storage cells (Favaretto, Santos, et al, 2015), and aerenchym extension (Caratti, 2019; Favaretto, Santos, et al, 2015).…”

“…These data suggest that early mowing of the weed, a few centimetres above ground level, could reduce weed growth. However, for this to be effective, it should be repeated often enough to deplete the root reserve (Favaretto, Santos, et al, 2015). Other mechanical methods such as ploughing decrease the number of E. plana plants but increase the bare soil area.…”