Woody Plant Architecture and Effects on Browsing Herbivores in Savannas

Author(s):  
Tristan Charles‐Dominique ◽  
Jean‐Francois Barczi ◽  
Simon Chamaillé‐Jammes
2011 ◽  
Vol 71 (2) ◽  
pp. 527-535 ◽  
Author(s):  
P. Dodonov ◽  
IC Lucena ◽  
MB Leite ◽  
DM Silva Matos

Studies of allometry are important in explaining effects of fire and herbivory, for estimating biomass in forests, and so on. There has been extensive research on plant allometry in temperate and tropical forests, showing that plant architecture often adjusts to the elastic similarity model, but not in Brazilian savannas (cerrado). We studied allometry of Dalbergia miscolobium, Diospyros hispida, Erythroxylum suberosum, Miconia albicans, M. ligustroides, Schefflera vinosa, and Xylopia aromatica in a cerrado sensu stricto area that was affected by a fire in August 2006. We expected that the study species would not adjust to any of the allometric models considered common for forest species ("constant stress", "elastic similarity", and "geometric growth"), and that there would be differences in allometry in burnt and unburnt patches. We sampled two species in 60 5 × 5 m contiguous plots placed in three transects, and five species in 100 5 × 5 m contiguous plots placed in five transects, where we measured the diameters at soil level (DSL) and the heights of all shoots. We used standardized major axis regressions on log-transformed data. The regression slope between the height and DSL was higher than 1.0 (p < 0.05) for four species, showing a greater height than would be expected under geometric growth, not predicted by theoretical models. We found significant differences (p < 0.05) in regression slopes and/or correlation coefficients between burnt and unburnt plots for five species, indicating that fire may influence plant allometry in the Brazilian cerrado, and that such a response is highly variable between species.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506a-506
Author(s):  
L.A. Klein ◽  
M.T. Windham ◽  
R.N. Trigiano

Microshoot and callus cultures of Cornus florida (flowering dogwood), which were grown on woody plant medium amended with BA, were inoculated with Microsphaera pulchra (an obligate plant parasite) by gently shaking infected leaves bearing numerous conidia over the tissue. Culture dishes were sealed with parafilm and incubated at 24 °C with 25 mol·m–2·s–1 provided by cool fluorescent bulbs for 15 h. Cultures were examined with a dissecting scope every 24 h and cultures transferred when contaminating fungi were present. Specimens were prepared light microscopy and SEM. The fungus infected individual callus cells, but did not sporulate. In contrast, powdery mildew was well-established (both primary and secondary hyphae) in 70% of the microshoot cultures after 6 days and sporulated on 20% by 7 to 8 days. The cellular relationship between host and pathogen in vitro was similar to that found in greenhouse-grown plants. This technique has possible applications in maintaining fungal culture collections and studying host–pathogen relationships under more stringently controlled conditions.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 503c-503
Author(s):  
Paul H. Henry ◽  
John E. Preece

A propagation method is being developed that allows softwood shoots to be generated from stem sections of dormant woody plant species. These shoots, forced in the greenhouse during the winter, are subsequently collected and processed as softwood stem cuttings to produce clonal plant material. Many species in the nursery industry can only be propagated using softwood cuttings, and this technique allows propagation of these species to be initiated several months earlier than what is typically possible. Current studies involve expanded screening of ornamental tree and shrub species to determine if commercial production using this technique is feasible. Results demonstrate that many species may be propagated using this method, but that some species are more prolific than others with respect to number of softwood shoots produced. Additional studies are currently in progress to determine the environmental (light regime, moisture regime) and cultural (type of media) conditions that are optimal when producing clonal plant material via this technique.


2018 ◽  
Vol 26 (1) ◽  
pp. 23-28
Author(s):  
Heri Adriwan Siregar ◽  
Hernawan Yuli Rahmadi ◽  
Retno Diah Setiowati ◽  
Edy Suprianto

An Attempt to combine the superior traits of Elaeis oleifera and Elaeis guineensis have been done through an interspecific hybrid cross and followed by pseudo-backcross 1 (pBC1). Observation of vegetative morphology and bunch components are presented in this paper. Two populations of pBC1 E. oleifera from the Suriname and Brazil origin were planted in 1990, 1993, 1995, and 2005, and were intensively observed for vegetative morphological properties and bunch components in November 2016 to February 2018. The results showed that almost all the individuals of pBC1 grew upright such as E. guineensis, no longer growing horizontally like the wild E. oleifera and the interspecific hybrid populations. The datas showed that the Suriname population plant architecture are compact or smaller than the Brazilian origin including the height increment and the size of the stem, the frond architecture and its components. Similarly, the bunch components show that the pBC1 Brazil is slightly superior to Suriname pBC1.


Author(s):  
Brian J. Wilsey

Conservation programs alter herbivore stocking rates and find and protect the remaining areas that have not been plowed or converted to crops. Restoration is an ‘Acid Test’ for ecology. If we fully understand how grassland systems function and assemble after disturbance, then it should be easy to restore them after they have been degraded or destroyed. Alternatively, the idea that restorations will not be equivalent to remnants has been termed the ‘Humpty Dumpty’ hypothesis—once lost, it cannot be put back together again. Community assembly may follow rules, and if these rules are uncovered, then we may be able to accurately predict final species composition after assembly. Priority effects are sometimes found depending on species arrival orders, and they can result in alternate states. Woody plant encroachment is the increase in density and biomass of woody plants, and it is strongly affecting grassland C and water cycles.


Author(s):  
Aihua Zhang ◽  
Qin Wang ◽  
Yidan He ◽  
Pengying Lai ◽  
Yifu Miu ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Grunewaldt-Stöcker ◽  
C. Popp ◽  
A. Baumann ◽  
S. Fricke ◽  
M. Menssen ◽  
...  

AbstractReplant disease is a worldwide phenomenon affecting various woody plant genera and species, especially within the Rosaceae. Compared to decades of intensive studies regarding replant disease of apple (ARD), the replant disease of roses (RRD) has hardly been investigated. The etiology of RRD is also still unclear and a remedy desperately needed. In greenhouse pot trials with seedlings of the RRD-sensitive rootstock Rosa corymbifera ‘Laxa’ cultured in replant disease affected soils from two different locations, early RRD symptom development was studied in fine roots. In microscopic analyses we found similarities to ARD symptoms with regards to structural damages, impairment in the root hair status, and necroses and blackening in the cortex tissue. Examinations of both whole mounts and thin sections of fine root segments revealed frequent conspicuous fungal infections in association with the cellular disorders. Particularly striking were fungal intracellular structures with pathogenic characteristics that are described for the first time. Isolated fungi from these tissue areas were identified by means of ITS primers, and many of them were members of the Nectriaceae. In a next step, 35 of these isolates were subjected to a multi-locus sequence analysis and the results revealed that several genera and species were involved in the development of RRD within a single rose plant. Inoculations with selected single isolates (Rugonectria rugulosa and Ilyonectria robusta) in a Perlite assay confirmed their pathogenic relationship to early necrotic host plant reactions, and symptoms were similar to those exhibited in ARD.


Author(s):  
Xin Huang ◽  
Julia Hilscher ◽  
Eva Stoger ◽  
Paul Christou ◽  
Changfu Zhu

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