Effects of flooding and shading on growth and gas exchange of Vochysia divergens Pohl (Vochysiaceae) of invasive species in the Brazilian Pantanal

Abstract

Vochysia divergens Pohl (commonly known as cambara) is a pioneer tree species that is native to the Amazon Basin but has been invading the seasonally flooded wetlands of the Brazilian Pantanal, forming monospecific communities. The physiological aspects associated with cambara invasion, including the effects of flooding and shading on growth and leaf gas exchange, are unknown but may shed light on why cambara is able to invade this novel habitat so rapidly. Thus, we conducted a manipulative experiment to quantify the effects of shading and flooding on the growth, gas exchange and leaf nutrient content of V. divergens saplings. Based on previous research we hypothesized that (1) experimental flooding would have no effect on the growth and gas exchange of V. divergens, and (2) experimental shading would reduce the growth and gas exchange of V. divergens regardless of the water treatment plants are subjected. Our data indicate that shading significantly increased the height, stomatal conductance (g s ), and transpiration (T) of V. divergens saplings, especially for plants exposed to normal irrigation. Experimental flooding significantly reduced rates of leaf production, plant height, and gas exchange; however, shaded plants exposed to flooding had a higher water use efficiency than plants exposed to full sun and flooding, because T was more depressed than net photosynthesis (A) in flooded plants exposed to full sun. Despite the inhibitory effects of flooding and shading, V. divergens saplings exhibited positive growth and C gain, regardless of the growth light environment or water level, indicating that the growth and leaf gas exchange of species is tolerant to both flooding and shading. Such tolerance to a wide variety of hydrological and growth light conditions presumably explains the ability of cambara to invade, and ultimately form dense, monospecific stands in the Brazilian Pantanal.

Shade effect on growth, yield, and shade tolerance of three peanut cultivars

“…As the result, the shaded plants height was taller than unshaded ones. The same thing happens on results research of Dalmolin et al (2012), and Ratri et al, (2015) that shading significantly increases plants height. Meanwhile, cultivar treatment gave different effects toward plants height at 14 DAP, 28 DAP and 42 DAP, but it was relatively the same on the last observation (56 DAP).…”

TEMPORAL VARIATION OF THE TOTAL PHENOLIC COMPOUNDS CONCENTRATION IN Vochysia divergens Pohl. (VOCHYSIACEAE) LEAVES IN THE BRAZILIAN PANTANAL

“…Little is known about the chemical composition and ecophysiological mecanisms of this species and its applications. It is considered as a weed or invader in fields and native grasslands causing problems for local ranchers (Nunes-da-Cunha and Junk, 2004;Santos et al, 2006), due to its plasticity and tolerance in relation to different intensities of flooding and light in the colonization of these areas (Dalmolin et al, 2012). Vochysia divergens has a strong physiological adaptation to flooded environment, with variations in its phenology according to the temporal fluctuation of the water level (Nunes-da-Cunha and Junk, 2000Junk, , 2004Dalmagro et al, 2013;Damolin et al, 2015).…”

Predicting flooding tolerance of native tree species to restore flooded forests

“…Flooding tolerance may vary not only due to different hydrological conditions, but also due to light conditions (Dalmolin et al ., 2012; Bender et al ., 2016; da Silva et al ., 2017). Growth responses under flooding will also depend on the season in which the plants are flooded; responses during the summer can be quite different from responses to flooding during winter (Crawford, 2003).…”