A Petri dish technique for the aseptic synthesis of ectomycorrhizae

1989 ◽  
Vol 67 (6) ◽  
pp. 1713-1716 ◽  
Author(s):  
Ken K. Y. Wong ◽  
J. André Fortin

An improved technique was developed for the aseptic synthesis of ectomycorrhizae in Petri dishes. Within 2 weeks after inoculation of a first-order lateral, ectomycorrhizae were formed on Larix laricina and Pinus banksiana with Hebeloma cylindrosporum, Laccaria bicolor, and Pisolithus tinctorius. The technique should be useful for addressing physiological and biochemical questions concerning microbial interactions with roots of whole plants.

1989 ◽  
Vol 67 (6) ◽  
pp. 1717-1726 ◽  
Author(s):  
Ken K. Y. Wong ◽  
Yves Piché ◽  
Diane Montpetit ◽  
Bradley R. Kropp

First-order laterals of Pinus banksiana seedlings were inoculated with variant strains of ectomycorrhizal Laccaria bicolor in an aseptic culture system. Macroscopic observations of 10 fungal strains indicated that 6 are mycorrhizal and 4 are apparently nonmycorrhizal. Furthermore, light microscopic examinations revealed significant intraspecific variation in mycorrhizal structures. The mean mantle thickness, mean mantle density, and mean Hartig net penetration of the six mycorrhizal strains ranged from 2.5 to 13.4 hyphae, 278 to 411 hyphae/mm and 2 to 2.8 root cell layers, respectively. Three of these strains formed fewer macroscopically observable mycorrhizae and developed significantly thinner mantles but their Hartig nets usually separated cortical cells more extensively. Three of the four apparently nonmycorrhizal strains showed infrequent and poor Hartig net development (mean penetration of 0.3 to 0.8 root cell layer), poor surface colonization, and no mantle development. These three strains were better able to colonize long roots. Only one strain could be considered truly nonmycorrhizal because it only colonized root surfaces poorly and never showed mantle or Hartig net formation. The observed intraspecific variability raises questions concerning the determinants of mycorrhiza development and structure.


1971 ◽  
Vol 49 (4) ◽  
pp. 501-504 ◽  
Author(s):  
F. H. Tainter ◽  
D. W. French

Formation of wound periderm appears to be a common form of resistance reaction in the Arceuthobium pusillum – Larix laricina combination, based on previous observations and an extensive examination of two witches' brooms of this host. Not only is wound periderm common in spur shoots within witches' brooms, but it also apparently restricts the development of the endophytic system in branchlets composing witches' brooms. Branchlets within witches' brooms of Pinus banksiana infected with A. pusillum and A. americanum also produced wound periderm similar to that described in eastern larch, which may account for the relative scarcity of aerial shoots on this host and restricted development of the endophytic system.


2021 ◽  
Author(s):  
Martina Badano Perez ◽  
Hugh J Beckie ◽  
Gregory R Cawthray ◽  
Danica E Goggin ◽  
Roberto Busi

AbstractOverreliance on herbicides for weed control is conducive to the evolution of herbicide resistance. Annual ryegrass (Lolium rigidum Gaud.) is a species that is prone to evolve resistance to a wide range of herbicide modes of action. Rapid detection of herbicide-resistant weed populations in the field can aid farmers to optimize the use of herbicides for their control. The feasibility of a portable agar-based test to rapidly and reliably detect annual ryegrass resistance to key herbicides such as clethodim, glyphosate, pyroxasulfone and trifluralin on-farm was investigated. The three research phases of this study show that: a) easy-to-interpret results are obtained with non-dormant seed from well-characterised susceptible and resistant populations, and resistance is detected as effectively as with traditional dose-response pot-based resistance assays. However, the test may not be suitable for portable use on-farm because of b) the low stability of some herbicides such as trifluralin and clethodim in agar and c) the tendency of seed dormancy in freshly-harvested seeds to confound the results. The agar-based test is best used as a research tool as a complement to confirm results obtained in traditional pot-based resistance screenings. Comprehensive agar test and / or whole-plant resistance tests by herbicide application at the recommended label rate (whole plants grown in pots) are the current benchmark for proactive in- and off-season resistance testing and should be promoted more widely to allow early detection of resistance, optimization of herbicide technology use and deploy appropriate weed management interventions.


1987 ◽  
Vol 65 (3) ◽  
pp. 500-504 ◽  
Author(s):  
Bradley R. Kropp ◽  
Brenda J. McAfee ◽  
J. André Fortin

The relative ability of sibling monokaryotic and reconstituted dikaryotic cultures of Laccaria bicolor (Maire) Orton to colonize short roots of Pinus banksiana Lamb. was studied using two different methods at 4, 8, and 12 months after isolation. Monokaryotic isolates varied in their ability to form ectomycorrhizae. Some lost the ability to colonize rootlets. Dikaryons formed soon after isolation from compatible mating type pairs were vigorous colonizers. A dikaryon formed after 12 months by pairing two competitive monokaryons formed abundant mycorrhizae. However, dikaryons formed after 12 months by using less competitive monokaryons showed a sharply reduced symbiotic ability. The isolation of one apparently nonmycorrhizal monokaryon is reported.


1989 ◽  
Vol 67 (9) ◽  
pp. 2663-2668 ◽  
Author(s):  
Rodney Arthur Savidge

Endogenous E-coniferin was characterized chemically and found to accumulate in cambia of Picea glauca, Pinus banksiana, Pinus strobus, and Larix laricina at the time of resumption of springtime cell-division activity and well before the initiation of lignification in differentiating tracheids. Coniferin content, quantified by high performance liquid chromatography, was highest on the centripetal side of the cambium, in developing xylem, at time of radial expansion of cambial derivatives. Stem ringing resulted in coniferin accumulation above the ring and disappearance below the ring. Coniferin was absent from leaves and dormant cambia. Exogenous coniferin was metabolized rapidly by in vitro cultures of P. strobus cambium grown on a defined medium containing the auxins 1-naphthalene acetic acid and indol-3-yl acetic acid and the cytokinin benzylaminopurine. The evidence suggests coniferin content of the cambium will be of practical value for determining commitment to and competence for wood formation in conifers.


2000 ◽  
Vol 30 (8) ◽  
pp. 1264-1274 ◽  
Author(s):  
D F Greene ◽  
E A Johnson

We developed and tested a wind-dispersal model of tree recruitment into burns from living sources at the fire edge or from small unburned residual stands. The model was also tested on recruitment of serotinous Pinus banksiana Lamb. within a burn. The model assumed that source strength is proportional to basal area density and that an individual (point source) recruitment curve can be expressed as a lognormal distribution. The model made significant predictions of the recruitment curves of Engelmann spruce (Picea engelmannii Parry ex Engelm.), white spruce (Picea glauca (Moench) Voss), and balsam fir (Abies balsamea (L.) Mill.) to distances as great as 2.0 km, although it tended to underpredict Abies and overpredict Picea. The model gave significant prediction of recruitment for jack pine (Pinus banksiana) within burns with seeds derived from aerial seed banks, and of white spruce and tamarck (Larix laricina (Du Roi) K. Koch) up to 100 m from residual stands. By forestry standards, burns are poorly stocked by those species that must obligately recruit from edges. In large fires, adequate stocking by a species such as white spruce that had 5 m2/ha of basal area would be limited to about 70 m from the edge. Small residual stands are expected to supply about half of all the recruits of white spruce or fir at distances exceeding about 800 m from a nominal burn edge.


1990 ◽  
Vol 28 (1-4) ◽  
pp. 557-561 ◽  
Author(s):  
Ken K.Y. Wong ◽  
Yves Piché ◽  
Diane Montpetit ◽  
J.André Fortin

1957 ◽  
Vol 35 (2) ◽  
pp. 133-138 ◽  
Author(s):  
O. Vaartaja

Seedlings of 10 tree species were tested under two widely different photo periodic conditions in environment otherwise near optimum. The amount of light given to the plants was the same under both conditions. Under the conditions simulating long photoperiods, the seedlings of all the species grew well and continued their growth during the 8-month experimental period. Under the short photoperiod, the following species remained nearly or fully dormant for several months beginning soon after germination: Larix laricina (Du Roi) K. Koch, Ulmus americana L., and two provenances of Picea glauca (Moench) Voss; the following species either remained nearly dormant or grew significantly slower than under the long day conditions: Betula lutea Michx. f., B. verrucosa Ehr., and Pinus banksiana Lamb.; P. resinosa Ait. was considered sensitive to photoperiods but its responses in appearance and growth were small; Caragana arborescens Lam., Thuja plicata Donn, and Acer negundo L. showed no significant response.


1986 ◽  
Vol 64 (6) ◽  
pp. 1224-1226 ◽  
Author(s):  
Bradley R. Kropp ◽  
J. A. Fortin

Protoplasts were released from dikaryotic mycelium of the ectomycorrhizal basidiomycete Laccaria bicolor using the lytic enzyme preparation NovoZyme 234. Protoplast release depended strongly on mycelium age, osmotic stabilizer, and temperature. The protoplasts could regenerate to form both monokaryotic and dikaryotic cultures capable of forming normal ectomycorrhizae with Pinus banksiana.


1968 ◽  
Vol 46 (11) ◽  
pp. 1397-1408 ◽  
Author(s):  
C. R. Janssen

A pollen diagram from a lake in the former bed of the eastern arm of Lake Agassiz in northern Minnesota records a vegetation of spruce forest followed by immigration successively of Pinus banksiana and (or) P. resinosa at 10 000 B.P., then Abies and Pteridium, and still later Alnus. Between 8000 and 7000 B.P. prairie and (or) Quercus savanna prevailed on the uplands, followed by deciduous forests of mainly Quercus, Ostrya virginiana, Fraxinus pennsylvanica, and possibly Populus sp.Slightly later, Pinus strobus migrated into the area, resulting in a gradual decline of pollen of deciduous forest types. Betula pollen, however, rises, and there is an indication of a return to prairie conditions prior to 3000 B.P.During the 8000–7000 B.P. dry interval the lowland vegetation consisted of fens of Typha latifolia, Dryopteris thelypteris, and Cyperaceae. Later paludification and lateral expansion of the peatland gave rise to rather rich swamps of Picea mariana, Larix laricina, Alnus rugosa, and Thuja occidentalis. There are some conspicuous peaks of Myrica in the pollen diagram.The time after 3000 B.P. is characterized by much Pinus strobus pollen and minima of deciduous trees and herbs. In the lowlands, formation of raised bogs and poor swamps and fens began, indicating a shift in climate towards wetter conditions. The arrival of white man in the area is reflected by the rise of Ambrosia. The shifts in overall peatland types are clearly accompanied by changes in the species composition of Pediastrum in Myrtle Lake, indicating corresponding changes in the lake waters.


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