Effect of four levels of shade on survival, morphology and chlorophyll fluorescence of Nothofagus alessandrii container-grown seedlings

Abstract

© iForest -Biogeosciences and Forestry IntroductionNothofagus alessandrii Espinosa (ruil) is a threatened and endemic tree of the Mediterranean zone of Chile (UICN 2001). At the beginning of the last century, ruil forests have been subjected to logging and burning to clear land for cultivation (Donoso & Landaeta 1983), leaving the remnant populations highly fragmented and surrounded by Pinus radiata D. Don plantations (Bustamante & Castor 1998). Current anthropogenic pressures on ruil forests led to consider such species as one of the most threatened trees in Chile. Today, the total area of ruil forests covers only 314 ha, decreasing by 11.8% in last 17 years (Santelices et al. 2012).The restoration of these forest ecosystems is a priority task, and calls for a better understanding of the factors that improve the seedling quality. However, in Chile, local authorities are still in the process of policy formulation, and there is no national recovering policy for the species. Besides, little information is available about the seedling cultivation of N. alessandrii (Santelices et al. 2011a(Santelices et al. , 2011b.It is recognized that seedlings of this species grow under the protection of adult trees and shaded by the understory. Shading is an important cultural practice for seedling quality and survival, especially for seedlings to be established in Mediterranean climate regions (Vázquez de Castro et al. 2014).The importance of shading for the development of Nothofagus genus species, including ruil, has been already reported (Santelices et al. 1995(Santelices et al. , 2011a(Santelices et al. , 2011b, and the shade-cloth method is widely used to protect plants from direct radiation (Landis et al. 1995). Shade promotes the development of morphological traits (Santelices et al. 2011a) and induces physiological responses in ruil nursery seedlings. However, no studies have examined the effects of shade on physiological response of N. alessandrii so far. Chlorophyll fluorescence has been increasingly used to understand both the mechanism of photosynthesis and the factors affecting it. Vidaver et al. (1989) suggested that chlorophyll fluorescence can rapidly provide useful information about photosynthetic responses to environmental stresses.The objective of this study was to evaluate the effects of three different shade levels and unshaded conditions on the survival, morphology, and chlorophyll fluorescence of N. alessandrii seedlings cultivated in containers. The study assessed the hypothesis that N. alessandrii seedlings require some degree of protection from direct sunlight in their early stages of development. Materials and Methods Plant materialThe N.alessandrii seeds were collected in a natural stand near the locality Lo Ramirez, Curepto Commune (35° 10′ S, 72° 06′ W, elevation 385 m a.s.l.), which is located in the province of Talca, Maule Region, Central Chile. Fruits were collected directly from the branches and transported to the nursery at the Catholic University del Maule (Talca, Chile). Seeds were cleaned a...

Shade tolerance response of legumes in terms of biomass accumulation, leaf photosynthesis, and chlorophyll pigment under reduced sunlight

“…Results from the current study support these explanations: species with similar chlorophyll concentrations at the start of the study also had similar chlorophyll fluorescence and by the end of the study, plants grown under shade had higher concentrations of chlorophyll and lower chlorophyll fluorescence. The differences in chlorophyll concentration due to shade in the current study are consistent with those reported earlier (Santelices et al., 2015; Wang et al., 2017).…”

Symbiotic Interaction Enhances the Recovery of Endangered Tree Species in the Fragmented Maulino Forest

“…This suggests that the optimal recruitment in N. alessandrii could be reached in forest gaps with intermediate levels of shade and moderate environmental stress (drought and light intensity). This is consistent with the results of Santelices et al (2015), who found that N. alessandrii seedlings performed better under intermediate shade (41-50% PAR) than under full sunlight conditions (100% PAR). In a recent study, Loewe et al (2017) experimentally evaluated the effects of shading and soil fertilization on the survival and stem length of N. alessandrii seedlings after one and two growing seasons under field conditions.…”

Dormancy Breaking, Germination, and Production of Mimosa Bimucronata (Dc.) Kuntze Seedlings

“…That is interesting since this species is considered as an early successional species in Brazil (Carvalho, 2004). Seedlings exposed to shaded conditions would allocate more biomass to stems and leaves, increasing their shoot/root ratio (Santelices et al, 2015). Higher mean of Mimosa bimucronata root biomass in larger containers resulted in more leaves only under shading, suggesting full sunlight inhibits biomass allocation to the shoot parts.…”