scholarly journals Susceptibility of Viburnum Species and Cultivars to Phytophthora ramorum

2010 ◽  
Vol 28 (4) ◽  
pp. 197-202 ◽  
Author(s):  
Timothy L. Widmer
Keyword(s):  
Leaf Area ◽  
Phytophthora Ramorum ◽  
Necrotic Area ◽  
Deciduous Species ◽  
Evergreen Species ◽  
Whole Plants

Abstract Phytophthora ramorum causes ramorum blight on Viburnum species, which are commonly grown as ornamentals. This study evaluated 24 different species or cultivars for susceptibility to P. ramorum. Whole plants were inoculated with an NA1 isolate of P. ramorum and placed in dew chambers at 20C (68F). After 5 days, the percentage of necrotic leaves for each plant and the percentage of necrotic area for each leaf were calculated. The percentage of necrotic leaves per plant ranged from 96.1% (V. tinus) to 7.9% (V. opulus ‘Notcutt’) and the percentage of necrotic leaf area ranged from 73.0% (V. × carlcephalum ‘Cayuga’) to 2.4% (V. trilobum ‘Wentworth’). In addition, six species or cultivars were evaluated for their susceptibility to a EU1 isolate of P. ramorum. The isolate had a significant effect on three of the six species or cultivars tested, although one isolate did not always yield the greatest necrosis. Evergreen species and cultivars had a higher percentage of necrotic leaves and higher percentage of necrotic leaf area than semi-evergreen or deciduous species and cultivars. All Viburnum species and cultivars showed some degree of susceptibility to P ramorum.

Instantaneous photosynthetic responses to temperature of deciduous and evergreen Nothofagus species

2006 ◽  
Vol 54 (3) ◽  
pp. 249 ◽  
Author(s):  
M. Kohout ◽  
J. Read
Keyword(s):  
Leaf Area ◽  
Maximum Rate ◽  
Net Photosynthesis ◽  
Growing Season ◽  
Carbon Gain ◽  
Deciduous Species ◽  
Sympatric Populations ◽  
Common Environment ◽  
Evergreen Species ◽  
Photosynthetic Responses

Deciduous species of Nothofagus tend to replace evergreen Nothofagus at the highest altitudes. We investigated whether deciduous Nothofagus species have higher maximum rates of net photosynthesis (Pmax) and specific leaf area (SLA) than evergreen species and whether there is an increasing photosynthetic advantage (e.g. higher Pmax) in deciduous species relative to evergreen species with increasing altitude that might explain their replacement of evergreen species. Net photosynthesis was investigated in (1) five deciduous and five evergreen species of Nothofagus grown in a common environment and (2) two co-occurring species, N. gunnii (Hook.f.) Oerst. (deciduous) and N. cunninghamii (Hook.) Oerst. (evergreen), across a range of altitudes in Tasmania. In the first experiment, the maximum rate of net photosynthesis per leaf mass (Pmax, mass) and SLA were higher in deciduous species, whereas the maximum rate of net photosynthesis per leaf area (Pmax, area) did not differ between leaf habits. However, in the field-based study, both mass- and area-based Pmax were higher in N. gunnii than N. cunninghamii across all sites. The high Pmax, mass of deciduous species may provide a competitive advantage at higher altitudes by maximising carbon gain during the growing season. However, in the study of sympatric populations of N. gunnii and N. cunninghamii there was no evidence of increasing photosynthetic advantage of the deciduous N. gunnii with increasing altitude.

scholarly journals Eco-physiological adaptation of dominant tree species at two contrasting karst habitats in southwestern China

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 122 ◽  
Author(s):  
Shouren Zhang ◽  
Dayong Fan ◽  
Qian Wu ◽  
Hui Yan ◽  
Xinwu Xu
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Woody Species ◽  
Physiological Adaptation ◽  
Southwestern China ◽  
Deciduous Species ◽  
Evergreen Species ◽  
Total N ◽  
Controlled Conditions ◽  
Karst Areas

The purpose of this study was to investigate the eco-physiological adaptation of indigenous woody species to their habitats in karst areas of southwestern China. Two contrasting forest habitats were studied: a degraded habitat in Daxiagu and a well-developed habitat in Tianlongshan, and the eco-physiological characteristics of the trees were measured for three growth seasons. Photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr) of the tree species in Daxiagu were 2-3 times higher than those in Tianlongshan under ambient conditions. However, this habitat effect was not significant when measurements were taken under controlled conditions. Under controlled conditions, Pn, gs, and Tr of the deciduous species were markedly higher than those for the evergreen species. Habitat had no significant effect on water use efficiency (WUE) or photochemical characteristics of PSII. The stomatal sensitivity of woody species in the degraded habitat was much higher than that in the well-developed habitat. Similarly, the leaf total nitrogen (N) and phosphorus (P) contents expressed on the basis of either dry mass or leaf area were also much higher in Daxiagu than they were in Tianlongshan. The mass-based leaf total N content of deciduous species was much higher than that of evergreen species, while leaf area-based total N and P contents of evergreens were significantly higher than those of deciduous species. The photosynthetic nitrogen- and phosphorus-use efficiencies (PNUE and PPUE) of deciduous species were much higher than those of evergreens. Further, the PPUE of the woody species in Tianlongshan was much higher than that  of the woody species in Daxiagu.The results from three growth seasons imply that the tree species were able to adapt well to their growth habitats. Furthermore, it seems that so-called “temporary drought stress” may not occur, or may not be severe for most woody plants in karst areas of southwestern China.

scholarly journals El Niño-Southern Oscillation affects the water relations of tree species in the Yucatan Peninsula, Mexico

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jorge Palomo-Kumul ◽  
Mirna Valdez-Hernández ◽  
Gerald A. Islebe ◽  
Manuel J. Cach-Pérez ◽  
José Luis Andrade
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Tropical Forests ◽  
Specific Leaf Area ◽  
Tree Species ◽  
Deciduous Species ◽  
Mature Trees ◽  
Seasonally Dry ◽  
Seasonally Dry Tropical Forests ◽  
Dry Tropical Forests

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.

Differential impact of liana colonization on the leaf functional traits of co-occurring deciduous and evergreen trees

2021 ◽  
Author(s):  
vivek pandi ◽  
Kanda Naveen Babu
Keyword(s):  
Functional Traits ◽  
Tree Species ◽  
Dry Matter Content ◽  
Differential Impact ◽  
Deciduous Species ◽  
Evergreen Species ◽  
Leaf Functional Traits ◽  
Leaf Trait ◽  
Host Trees ◽  
Significant Difference

Abstract The present study was carried out to analyse the leaf functional traits of co-occurring evergreen and deciduous tree species in a tropical dry scrub forest. This study also intended to check whether the species with contrasting leaf habits differ in their leaf trait plasticity, responding to the canopy-infestation by lianas. A total of 12 leaf functional traits were studied for eight tree species with contrasting leaf habits (evergreen and deciduous) and liana-colonization status (Liana+ and Liana−). In the liana-free environment (L−), evergreen trees had significantly higher specific leaf mass (LMA) and leaf dry matter content (LDMC) than the deciduous species. Whereas, the deciduous trees had higher specific leaf area (SLA) and mass-based leaf nitrogen concentration (Nmass). The leaf trait-pair relationship in the present study agreed to the well-established global trait-pair relationships (SLA Vs Nmass, Lth Vs SLA, Nmass Vs Lth, Nmass Vs LDMC, LDMC Vs SLA). There was no significant difference between L+ and L− individuals in any leaf functional traits studied in the deciduous species. However, evergreen species showed marked differences in the total chlorophyll content (Chlt), chlorophyll b (Chlb), SLA, and LMA between L+ and L− individuals of the same species. Deciduous species with the acquisitive strategy can have a competitive advantage over evergreen species in the exposed environment (L−) whereas, evergreen species with shade-tolerant properties were better acclimated to the shaded environments (L+). The result revealed the patterns of convergence and divergence in some of the leaf functional traits between evergreen and deciduous species. The results also showed the differential impact of liana colonization on the host trees with contrasting leaf habits. Therefore, liana colonization can significantly impact the C-fixation strategies of the host trees by altering their light environment. Further, the magnitude of such impact may vary among species of different leaf habits. The increased proliferation of lianas in the tropical forest canopies may pose a severe threat to the whole forest carbon assimilation rates.

Architectural differences in saplings of temperate versus tropical angiosperms; consequences of the deciduous habit?

2005 ◽  
Vol 83 (11) ◽  
pp. 1391-1401 ◽  
Author(s):  
David A. King
Keyword(s):  
High Frequency ◽  
Plant Architecture ◽  
Tropical Species ◽  
Deciduous Species ◽  
Evergreen Species ◽  
Crown Shape ◽  
Temperate Deciduous ◽  
Lower Height ◽  
Filtering Effect ◽  
Overstory Trees

The architecture of saplings of temperate deciduous species of the southeastern United States was compared with that of tropical evergreen species of Central America, Borneo, and northeastern Australia. The deciduous species were more planar in the understory than were the tropical species, because of (i) more planar leaf displays within branches, (ii) a high frequency of arching, plagiotropic main stems (associated with greater plasticity in crown symmetry in relation to light), and (iii) a lower height of first branching. The deciduous species also had more planar branches than did subtropical and temperate evergreen angiosperms. This greater planarity in temperate deciduous understories may be associated with the simultaneous positioning of most leaves during a single flush in the spring. In contrast, saplings in tropical understories typically bear multiple leaf cohorts and position new leaves at the peripheries of existing leaf displays. These results and those of other studies suggest that there are adaptive links between plant architecture and phenology. Other factors, such as latitudinal variation in sun angles, may influence crown shape in overstory trees, but did not seem to be involved here, possibly because the filtering effect of the canopy results in smaller latitudinal shifts in understory illumination angles during the growing season. Thus, by favouring the deciduous habit, the cold winters and warm, humid summers of the eastern deciduous biome of North America appear to have had a notable influence on sapling architecture.

scholarly journals Effect of Temperature and Moisture Period on Infection of Rhododendron ‘Cunningham's White’ by Phytophthora ramorum

2009 ◽  
Vol 99 (9) ◽  
pp. 1045-1052 ◽  
Author(s):  
Paul W. Tooley ◽  
Marsha Browning ◽  
Kerrie L. Kyde ◽  
Dana Berner
Keyword(s):  
The United States ◽  
Phytophthora Ramorum ◽  
Effect Of Temperature ◽  
Optimum Temperature ◽  
Detached Leaf ◽  
Wide Range ◽  
Effects Of Temperature ◽  
Gradient Plate ◽  
Whole Plants ◽  
Moisture Conditions

We investigated the temperature and moisture conditions that allow Phytophthora ramorum to infect Rhododendron ‘Cunningham's White’. Most experiments were performed with a single P. ramorum isolate from the NA1 clonal lineage. For whole plants incubated in dew chambers at 10 to 31°C, the greatest proportion of diseased leaves, 77.5%, occurred at the optimum temperature of 20.5°C. Disease occurred over the entire range of temperatures tested, although amounts of disease were minor at the temperature extremes. For whole plants exposed to varying dew periods at 20°C and then incubated at 20°C for 7 days, a dew period as short as 1 h resulted in a small amount of disease; however, at least 4 h of dew were required for >10% of the leaves to become diseased. Moisture periods of 24 and 48 h resulted in the greatest number of diseased leaves. In detached-leaf, temperature-gradient-plate experiments, incubation at 22°C resulted in the greatest disease severity, followed by 18°C and then 14°C. In detached-leaf, moisture-tent experiments, a 1-h moisture period was sufficient to cause disease on 67 to 73% of leaves incubated for 7 days at 20°C. A statistical model for disease development that combined the effects of temperature and moisture period was generated using nonlinear regression. Our results define temperature and moisture conditions which allow infection by P. ramorum on Cunningham's White rhododendron, and show that P. ramorum is able to infect this host over a wide range of temperatures and moisture levels. The results indicate that P. ramorum has the potential to become established in parts of the United States that are outside its current range.

Relationship Between Leaf Area Index and Atmospheric Cooling of Tree Species

2019 ◽  
Vol 42 (3) ◽  
pp. 203-208
Author(s):  
S. K. Gupta ◽  
◽  
Jeet Ram ◽  
Hukum Singh ◽  
◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Mangifera Indica ◽  
Climatic Conditions ◽  
Tree Canopy ◽  
Strong Positive Correlation ◽  
Evergreen Species ◽  
Terrestrial Environment ◽  
Area Index ◽  
Effective Measure

Presence of tree canopy is known to strongly influence ambient temperature and other micro-climatic conditions underneath. Therefore, planting trees with close or dense crown can be used as effective measure to provide thermal cover to species of flora and fauna adapted to shady and cooler environment. The cooling produced by a tree is exclusively the combined results of physical and physiological functions of its canopy. Tree canopy is one of the most important, physiologically active components that establish interaction between the terrestrial environment and the atmosphere which regulates various bio-physiological processes. Leaf Area Index (LAI) is one of the most reliable indicators of growth and vigour of a tree. We compared LAI and corresponding understory temperature of a few isolated trees of Ficus benjamina, Mangifera indica, Anthocephalus chinensis, Lagerstroemia floribunda and Peltophorum africanum belonging to evergreen, semi-deciduous and deciduous nature to establish the relationship between the two parameters. A great variation in LAIs of deciduous and semi-deciduous species was observed on account of leaf shedding and fast development of crown after emergence of new leaves whereas the variation was lesser in evergreen species. A strong positive correlation was found between LAI and cooling produced by A. chinensis, L. floribunda and P. africanum whereas no linear relation was established in case of M. indica and F. benjamina.

scholarly journals Phenology and water relations of eight woody species in the Coronation Garden of Kirtipur, central Nepal

1970 ◽  
Vol 4 (6) ◽  
pp. 49-56
Author(s):  
Bharat B Shrestha ◽  
Yadav Uprety ◽  
Keshav Nepal ◽  
Sandhya Tripathi ◽  
Pramod K Jha
Keyword(s):  
Woody Species ◽  
Dry Season ◽  
Elastic Tissue ◽  
Deciduous Species ◽  
Evergreen Species ◽  
Central Nepal ◽  
Relative Water ◽  
Bauhinia Variegata ◽  
Celtis Australis ◽  
Woodfordia Fruticosa

Phenological activities of eight woody species planted in Kirtipur (central Nepal) were examined, each for one dry season between September 2001 and June 2003. From Pressure Volume (P-V) analysis, we determined relative water content at zero turgor (RWCz), osmotic potential at zero turgor (Ψsz) and full turgor (Ψsf ), and bulk modulus of elasticity (ε) once a month through the course of dry season. Both evergreen species (Cotoneaster bacillaris Wall., Quercus lanata Sm., Ligustrum confusum Decne., Woodfordia fruticosa (L.) Kurz.) and deciduous species (Celtis australis Linn., Alnus nepalensis D.Don., Bauhinia variegata Linn. and Lagerstroemia indica Linn.) put out their new leaves during the dry summer when day length and temperature were increasing. Generally, bud break coincided with concentrated leaf fall during the dry summer and the leaf fall reduced total leaf area to its lowest value. The deciduous species were leafless for one to three months, followed by a prolonged period of leaf production and shoot elongation. Evergreen and deciduous species manifested distinct adaptive strategies to water deficit. Evergreens can reduce osmotic potential (Ψs) to its low value and maintain proper water potential (Ψ) gradient from soil to plant, which facilitates absorption of water during dry season. Elastic tissue in deciduous species is coupled with leaf shedding during the dry season; both factors may help maintain proper Ψs for new growth during dry period. One evergreen species (Woodfordia fruticosa) and three deciduous species (Celtis australis, Bauhinia variegata and Lagerstroemia indica) have inherently high dehydration tolerance due to their elastic tissue. During drought there has been osmotic adjustment in Quercus lanata, and elastic adjustment in Ligustrum confusum, Celtis australis and Lagerstroemia indica. Key words: Himalayas, Pressure Volume (P-V) curve, relative water content (RWC), osmotic adjustment, elastic adjustment Himalayan Journal of Sciences Vol.4(6) 2007 p.49-56

Screening Selected Gulf Coast and Southeastern Forest Species for Susceptibility to Phytophthora ramorum

2013 ◽  
Vol 14 (1) ◽  
pp. 17 ◽  
Author(s):  
Jason A. Preuett ◽  
Daniel J. Collins ◽  
Douglas Luster ◽  
Timothy L. Widmer
Keyword(s):  
Leaf Area ◽  
Gulf Coast ◽  
The United States ◽  
Phytophthora Ramorum ◽  
Average Percentage ◽  
Magnolia Grandiflora ◽  
Black Willow ◽  
Lindera Benzoin ◽  
Southeastern Us ◽  
Parthenocissus Quinquefolia

Phytophthora ramorum, the causal agent of sudden oak death, poses a threat to woody plants in the rest of the United States. Several plant species native to Gulf Coast and southeastern US forests were tested for reaction to P. ramorum, including eastern baccharis (Baccharis halmifolia), spicebush (Lindera benzoin), yaupon (Ilex vomitoria), southern magnolia (Magnolia grandiflora), sweetbay magnolia (M. virginiana), Virginia creeper (Parthenocissus quinquefolia), black willow (Salix nigra), and baldcypress (Taxodium distichum). The foliage of each species was inoculated with a zoospore suspension and placed in a dew chamber for 5 days. The average percentage of leaf area necrosis was 0.2, 4.9, 27.9, 32.1, 8.6, 1.5, 1.1, 0.2, and 5.0% for inoculated eastern baccharis, spicebush, yaupon, southern magnolia, sweetbay magnolia, Virginia creeper (Louisiana), Virginia creeper (Maryland), black willow, and baldcypress, respectively. Comparison of the percent necrotic leaf area between inoculated and non-inoculated plants showed significant differences (P ≤ 0.05) for yaupon (P = 0.0008), southern magnolia (P = 0.001), and sweetbay magnolia (P = 0.0009). The other species did not show significant differences although infection was confirmed on spicebush, Virginia creeper, and baldcypress. This is a first report of yaupon, sweetbay magnolia, and baldcypress being hosts of P. ramorum. Accepted for publication 2 April 2013. Published 30 July 2013.

Growth-inhibiting Fungicides Affect Detection of Phytophthora ramorum from Infected Foliage and Roots

2014 ◽  
Vol 15 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Nina Shishkoff
Keyword(s):  
Root Colonization ◽  
Leaf Tissue ◽  
Phytophthora Ramorum ◽  
Infected Leaf ◽  
Inoculum Production ◽  
Affect Detection ◽  
Flow Through ◽  
Whole Plants ◽  
Infected Leaf Tissue ◽  
Growth Inhibiting

Growth-inhibiting fungicides are used routinely to control common and regulated Oomycete pathogens. This study investigated whether such fungicides could affect detection of Phytophthora ramorum from plant tissue, both foliage and roots. Whole plants of Rhododendron × ‘Cunningham's White’ were inoculated with P. ramorum and treated 3 days later with fosetyl-Al, mefenoxam, or propamocarb. The foliage was sampled over time to see if fungicides prevented successful culturing of the pathogen from infected leaf tissue or interfered with detection using real-time PCR or ELISA. Mefenoxam significantly reduced the ability to culture the pathogen from leaves for the first 6 weeks while recovery from leaves treated with other fungicides did not differ from water-treated controls; detection using PCR or ELISA was not affected by fungicide application. The roots of Viburnum cuttings were inoculated with P. ramorum and then treated 4 days later with fosetyl-Al, mefenoxam, or propamocarb. The amount of inoculum in flow through water samples taken weekly for 5 weeks was quantified and percent root colonization determined at the end of the experiment. Propamocarb had no effect on inoculum production or root infection, while viable inoculum production was significantly decreased in fosetyl-Al- or mefenoxam-treated plants over 5 weeks, and root colonization was significantly decreased. Accepted for publication 23 January 2014. Published 18 March 2014.

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