Abstract
Taking into account the occurrence of Ocotea pulchella in areas subjected to periodic flooding, this work aimed to evaluate the survival and initial development of Ocotea pulchella seedlings (2 months old) and juveniles (9 months old) in response to waterlogging under different light regimes by varying both light quantity and light quality, in order to test for possible flood tolerance of the species as affected by light conditions. Three levels of soil moisture (field capacity, mean flooding - only for seedlings - and full flooding) and four light treatments (full sun, neutral shade, far red enriched shading and neutral plus far red) were tested. The survival of seedlings and juveniles during one year was relatively high, whereas growth was negatively affected by full sun and flooding. Seedling growth was inhibited by soil waterlogging whatever the light condition, whereas plant growth at field capacity and mean fl ooding was similar. Flooding also inhibited the growth of juveniles, and that response was practically not affected by the light regimes. The results suggest that Ocotea pulchella seedlings can survive in the understory, even in areas subject to fl ooding, forming a slow-growth seedling bank. The species seems to tolerate relatively long-term soil waterlogging when kept out of direct sunlight. Otherwise, responses of waterlogged plants to shading seem to be aff ected by irradiance and light quality.
Highlights
Plant growth is an integrated response controlled by interactions of genotype and environmental factors such as light and water. Montgomery and Chazdon (2002) report that several studies demonstrate that light availability on the forest floor plays an important role in growth, survival and life history of tree seedlings and saplings, with some species being able to germinate and grow below a canopy, whereas others need some increase in solar radiation for growth
The mean percentage of juveniles alive at ‘fc’ was nearly constant during the entire 12-month period, and waterlogging caused a decrease in the number of survivors in all the light treatments (Figures 1B, D, F, H), the effect appeared to be more pronounced in plants covered only with failet (Figure 1F)
Three-month-old Ocotea pulchella seedlings survived better under shaded conditions than in S, suggesting that seedling survival can be more favored under canopy than in open environments, S irradiance recorded in this work can be higher than irradiance recorded in Restinga forest gaps (Pires 2006)
Summary
Plant growth is an integrated response controlled by interactions of genotype and environmental factors such as light and water. Montgomery and Chazdon (2002) report that several studies demonstrate that light availability on the forest floor plays an important role in growth, survival and life history of tree seedlings and saplings, with some species being able to germinate and grow below a canopy, whereas others need some increase in solar radiation for growth. Several reports have studied the effect of shade on the growth of tree species, most have focused only on the effects of decreasing the irradiance (Souza & Valio 2003) and did not take into account the changes in light quality (red/ far red ratio). The “shade” under the forest canopy is characterized both by a decrease of the photon flux density and the red/far-red ratio, and most of the field studies on the effect of natural shading do not discriminate between light quantity and light quality, they may be of some advantage when interpreting the effects of shade on growth, since the concept of shade-tolerance does not discriminate between these effects (Souza & Valio 2003). Some reports suggest that the species response to soil water status can be changed by shading, the effect of water treatment seems to be dominant over that of irradiance (Dale & Causton 1992; Ferreira et al 1991)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
