Biotechnological Approaches for the Improvement and Conservation of Alnus glutinosa (L.) Gaertner

Author(s):  
Mª del Carmen San José ◽  
Laura V. Janeiro ◽  
Mª Teresa Martínez ◽  
Silvia Valladares ◽  
Mª José Cernadas ◽  
...  
Keyword(s):  
1999 ◽  
Vol 64 ◽  
Author(s):  
D. Van den Meersschaut ◽  
B. De Cuyper ◽  
K. Vandekerkhove ◽  
N. Lust

Natural  stand changes in the forest reserve of Liedekerke were analysed during the  period    1986-1996, using a permanent grid of circular plots. The monitoring  concentrated on natural    changes in species composition, using stem number and basal area as  indicators, and changes    in spatial distribution and colonization capacities of trees and shrubs,  with special interest in the    competition between exotic and indigenous species. After only a decade of  monitoring important    natural changes in the woody layer were detected. The pioneer forest is  gradually maturing    through self-thinning processes and shifts in species composition. The  overall stem number    decreased with 33.6%, while the basal area increased with 20.9%. Birch (Betula pendula/    pubescens) and indigenous oak (Quercus robur/petraea) remained  dominant. More tolerant    exotic species, like red oak (Quercus rubra) and sweet chestnut (Castanea  sativa), are slowly    increasing their share in the species composition and expanding their  range. Pioneer species on    the other hand, like aspen (Populus tremula), willow (Salix  capreaicinerealaurita), alder buckthorn    (Frangula alnus) and  common (Alnus glutinosa)  and grey alder (A. incana),  strongly declined.    Black cherry (Prunus serotina) seems to be slowly invading the forest due to its  massive    natural regeneration. Strong competition may be expected especially from  rowan ash (Sorbus    aucuparia), which showed similar regeneration  and colonization capacities. Elder (Sambucus    nigra) dramatically extented its range, though  its share remains marginal. Beech remained absent    most probably due to the lack of mature trees in the vacinity of the  forest. Finally this    change detection allowed that general predictions could be made on the  future natural development    and composition of this forest reserve, which could serve forest management  decisions.


Author(s):  
A P Glinushkin ◽  
E M Motasova ◽  
T P Aysuvakova ◽  
A V Ovsiankina ◽  
N S Zhemchuzhina ◽  
...  

1981 ◽  
Vol 89 (2) ◽  
pp. 321-326 ◽  
Author(s):  
JAN BLOM ◽  
WIM ROELOFSEN ◽  
ANTOON D. L. AKKERMANS
Keyword(s):  

1995 ◽  
Vol 73 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Tadeusz Kowalski ◽  
Rolf D. Kehr

Two new species of Phialocephala were isolated from the periderm of living branches of forest trees in Germany. In culture, Phialocephala compacta Kowalski & Kehr sp.nov., found on Alnus, is characterized by crowded conidiogenous heads that become deeply pigmented with age. Phialocephala scopiformis Kowalski & Kehr sp.nov., isolated from Picea and other conifers, develops elongated, complex conidiogenous heads with up to 15 series of branches in culture. The taxonomic placement of both new species and their role in endophytism and in natural pruning of branches is discussed. Key words: Picea abies, Alnus glutinosa, Phialocephala compacta, Phialocephala scopiformis, branch pruning fungi.


1986 ◽  
Vol 64 (10) ◽  
pp. 2216-2226 ◽  
Author(s):  
Yves Prin ◽  
Mireille Rougier

The aim of the present study was to investigate the Alnus root surface using seedlings grown axenically. This study has focused on root zones where infection by the symbiotic actinomycete Frankia takes place. The zones examined extend from the root cap to the emerging root hair zone. The root cap ensheaths the Alnus root apex and extends over the root surface as a layer of highly flattened cells closely appressed to the root epidermal cell wall. These cells contain phenolic compounds as demonstrated by various histochemical tests. They are externally bordered by a thin cell wall coated by a thin mucilage layer. The root cap is ruptured when underlying epidermal cells elongate, and cell remnants are still found in the emerging root hair zone. Young emerging root hairs are bordered externally by a cell wall covered by a thin mucilage layer which reacts positively to the tests used for the detection of polysaccharides, glycoproteins, and anionic sites. The characteristics of the Alnus root surface and the biological function of mucilage and phenols present at the root surface are discussed in relation to the infection process.


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