scholarly journals Shifting from acquisitive to conservative: the effects of Phoradendron affine (Santalaceae) infection in leaf morpho-physiological traits of a Neotropical tree species

2017 ◽  
Vol 65 (1) ◽  
pp. 31 ◽  
Author(s):  
Marina Corrêa Scalon ◽  
Sabrina Alves dos Reis ◽  
Davi Rodrigo Rossatto

Mistletoes are parasitic plants that penetrate the host branches through a modified root and connect to their xylem to acquire nutrients and water. Under mistletoe infection, resources that would otherwise be used by the host are stolen by the parasite. Our aim was to compare leaf morpho-physiological traits between healthy uninfected branches and mistletoe-infected branches of a Neotropical tree species (Handroanthus chrysotrichus (Mart. ex DC.) Mattos – Bignoniaceae). We also investigated differences between mistletoe and host leaf traits. Morphological (petiole length and thickness, leaf area and thickness, and specific leaf area) and physiological leaf traits (pre-dawn and midday water potential) were measured in 10 individuals infected with the mistletoe Phoradendron affine (Pohl ex DC.) Engl. & K.Krause (Santalaceae). Mistletoes showed smaller and thicker leaves with lower pre-dawn and midday water potential, suggesting that mistletoes are more profligate water users than the host. Host leaves from infected branches were scleromorphic and showed stronger water-use control (less negative water potential) than host leaves from uninfected branches. Our results indicated that leaves from infected branches shifted to a more conservative resource-use strategy as a response to a water and nutrient imbalance caused by mistletoe infection.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jorge Palomo-Kumul ◽  
Mirna Valdez-Hernández ◽  
Gerald A. Islebe ◽  
Manuel J. Cach-Pérez ◽  
José Luis Andrade

AbstractWe evaluated the effect of ENSO 2015/16 on the water relations of eight tree species in seasonally dry tropical forests of the Yucatan Peninsula, Mexico. The functional traits: wood density, relative water content in wood, xylem water potential and specific leaf area were recorded during the rainy season and compared in three consecutive years: 2015 (pre-ENSO conditions), 2016 (ENSO conditions) and 2017 (post-ENSO conditions). We analyzed tree size on the capacity to respond to water deficit, considering young and mature trees, and if this response is distinctive in species with different leaf patterns in seasonally dry tropical forests distributed along a precipitation gradient (700–1200 mm year−1). These traits showed a strong decrease in all species in response to water stress in 2016, mainly in the driest site. Deciduous species had lower wood density, higher predawn water potential and higher specific leaf area than evergreen species. In all cases, mature trees were more tolerant to drought. In the driest site, there was a significant reduction in water status, regardless of their leaf phenology, indicating that seasonally dry tropical forests are highly vulnerable to ENSO. Vulnerability of deciduous species is intensified in the driest areas and in the youngest trees.


2010 ◽  
Vol 67 (6) ◽  
pp. 624-632 ◽  
Author(s):  
Keila Rego Mendes ◽  
Ricardo Antonio Marenco

Global climate models predict changes on the length of the dry season in the Amazon which may affect tree physiology. The aims of this work were to determine the effect of the rainfall regime and fraction of sky visible (FSV) at the forest understory on leaf traits and gas exchange of ten rainforest tree species in the Central Amazon, Brazil. We also examined the relationship between specific leaf area (SLA), leaf thickness (LT), and leaf nitrogen content on photosynthetic parameters. Data were collected in January (rainy season) and August (dry season) of 2008. A diurnal pattern was observed for light saturated photosynthesis (Amax) and stomatal conductance (g s), and irrespective of species, Amax was lower in the dry season. However, no effect of the rainfall regime was observed on g s nor on the photosynthetic capacity (Apot, measured at saturating [CO2]). Apot and leaf thickness increased with FSV, the converse was true for the FSV-SLA relationship. Also, a positive relationship was observed between Apot per unit leaf area and leaf nitrogen content, and between Apot per unit mass and SLA. Although the rainfall regime only slightly affects soil moisture, photosynthetic traits seem to be responsive to rainfall-related environmental factors, which eventually lead to an effect on Amax. Finally, we report that little variation in FSV seems to affect leaf physiology (Apot) and leaf anatomy (leaf thickness).


2012 ◽  
Vol 28 (5) ◽  
pp. 527-530 ◽  
Author(s):  
Carl F. Salk

Plants have an inherent flexibility to respond to different environmental conditions. One axis of plant ecophysiological strategy is seen in the spectrum of leaf functional traits. Flexibility in these traits would be suggestive of plants’ phenotypic plasticity in response to environmental changes. This research seeks to identify differences between leaves of sprout and non-sprout shoots of a broad ecological range of neotropical tree species. Using a functional-trait approach, this study assesses a large pool of species for within-species physiological flexibility. Leaf mass per area (LMA) and leaf area were measured for plants of sprout and non-sprout origin for 26 tree species grown in a reforestation plantation in Panama. Sprouts had a consistently lower LMA than non-sprouts, but there was no consistent pattern for leaf area. These trends show that sprouts are more like pioneer species than conspecific saplings, a finding in general agreement with fast sprout growth seen in previous studies. Further, later-successional (high LMA) species showed a greater reduction of LMA in sprouts. These results show that tropical tree species adjust physiologically to changing ecological roles and suggest that certain species may be more resilient than realized to changing climate and disturbance patterns.


2014 ◽  
Vol 11 (24) ◽  
pp. 7331-7347 ◽  
Author(s):  
K. J. Bloomfield ◽  
T. F. Domingues ◽  
G. Saiz ◽  
M. I. Bird ◽  
D. M. Crayn ◽  
...  

Abstract. Forest and savanna are the two dominant vegetation types of the tropical regions with very few tree species common to both. At a broad scale, it has long been recognised that the distributions of these two biomes are principally governed by precipitation and its seasonality, but with soil physical and chemical properties also potentially important. For tree species drawn from a range of forest and savanna sites in tropical Far North Queensland, Australia, we compared leaf traits of photosynthetic capacity, structure and nutrient concentrations. Area-based photosynthetic capacity was higher for the savanna species with a steeper slope to the photosynthesis ↔ nitrogen (N) relationship compared with the forest group. Higher leaf mass per unit leaf area for the savanna trees derived from denser rather than thicker leaves and did not appear to restrict rates of light-saturated photosynthesis when expressed on either an area or mass basis. Median ratios of foliar N to phosphorus (P) were relatively high (>20) at all sites, but we found no evidence for a dominant P limitation of photosynthesis for either forest or savanna trees. A parsimonious mixed-effects model of area-based photosynthetic capacity retained vegetation type and both N and P as explanatory terms. Resulting model-fitted predictions suggested a good fit to the observed data (R2 = 0.82). The model's random component found variation in area-based photosynthetic response to be much greater among species (71% of response variance) than across sites (9%). These results suggest that, on a leaf-area basis, savanna trees of Far North Queensland, Australia, are capable of photosynthetically outperforming forest species at their common boundaries.


2015 ◽  
Vol 42 (4) ◽  
pp. 423 ◽  
Author(s):  
Shi-Dan Zhu ◽  
Ya-Jun Chen ◽  
Kun-Fang Cao ◽  
Qing Ye

Plant functional traits are closely associated with plant habitats. In this study, we investigated the interspecific variations in stem and leaf hydraulics, xylem and leaf anatomy, gas-exchange rates and leaf pressure–volume relationships among three Syzygium tree species in early, mid- and late successional tropical forests. The objective was to understand the response and adaptation of congeneric species, in terms of branch and leaf functional traits, to different environments. A consistent pattern of decline with succession was evident in leaf and sapwood specific hydraulic conductivity (ks), maximum leaf hydraulic conductance (Kleaf), and photosynthetic rates for the three Syzygium species. Variations of ks and Kleaf were correlated with changes in vessel anatomy (i.e. vessel density and diameter) and leaf flux-related structure (i.e. stomatal pore index and vein density) respectively. However, specific leaf area and leaf to sapwood area ratio did not significantly differ among the three species. In addition, the mid-successional species had the lowest values of leaf water potential at full turgor and turgor loss point and 50% loss of Kleaf, but the greatest value of xylem water potential at 50% loss of ks. Our results demonstrate that leaf and branch traits associated with photosynthesis and/or hydraulic conductance, rather than those associated with drought tolerance, are the key factors underlying the response and adaptation of the three Syzygium tree species along the tropical forest succession.


2014 ◽  
Vol 11 (6) ◽  
pp. 8969-9011 ◽  
Author(s):  
K. J. Bloomfield ◽  
T. F. Domingues ◽  
G. Saiz ◽  
M. I. Bird ◽  
D. M. Crayn ◽  
...  

Abstract. Forest and savanna are the two dominant vegetation types of the tropical regions with very few tree species common to both. Aside from precipitation patterns, boundaries between these two vegetation types are strongly determined by soil characteristics and nutrient availability. For tree species drawn from a range of forest and savanna sites in tropical far north Queensland, Australia, we compared leaf traits of photosynthetic capacity, structure and nutrient concentrations. Area-based photosynthetic capacity was higher for the savanna species with a steeper slope to the photosynthesis ↔ Nitrogen relationship compared with the forest group. Higher leaf mass per unit leaf area for the savanna trees derived from denser rather than thicker leaves and did not appear to restrict rates of light-saturated photosynthesis when expressed on either an area- or mass-basis. Median ratios of foliar N to phosphorus were above 20 at all sites, but we found no evidence for a dominant P-limitation of photosynthesis for the forest group. A parsimonious mixed-effects model of area-based photosynthetic capacity retained vegetation type and both N and P as explanatory terms. Resulting model-fitted predictions suggested a good fit to the observed data (R2 = 0.82). The model's random component found variation in area-based photosynthetic response to be much greater among species (71% of response variance) than across sites (9%). These results suggest that in leaf area-based photosynthetic terms, savanna trees of far north Queensland, Australia are capable of out-performing forest species at their common boundaries1. 1 Adopted symbols and abbreviations are defined in Table 5.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 522d-522 ◽  
Author(s):  
J.W. Buxton ◽  
D.L. Ingram ◽  
Wenwei Jia

Geraniums in 15-cm pots were irrigated automatically for 8 weeks with a Controlled Water Table (CWT) irrigation system. Plants were irrigated with a nutrient solution supplied by a capillary mat with one end of the mat suspended in a trough below the bottom of the pot. The nutrient solution remained at a constant level in the trough. Nutrient solution removed from the trough was immediately replaced from a larger reservoir. The vertical distance from the surface of the nutrient solution and the bottom of the pot determined the water/air ratio and water potential in the growing media. Treatments consisted of placing pots at 0, 2, 4, and 6 cm above the nutrient solution. Control plants were irrigated as needed with a trickle irrigation system. Geraniums grown at 0,2 and 4 CWT were ≈25% larger than the control plants and those grown at 6 CWT as measured by dry weight and leaf area. Roots of plants grown at 0 CWT were concentrated in the central area of the root ball; whereas roots of plants in other treatments were located more near the bottom of the pot. Advantages of the CWT system include: Plant controlled automatic irrigation; no run off; optimum water/air ratio.


2021 ◽  
Author(s):  
Tatiane Viegas Debiasi ◽  
Anderson Kikuchi Calzavara ◽  
Ladaslav Sodek ◽  
Halley Caixeta Oliveira

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