Soil biotic and abiotic effects on seedling growth exhibit context dependent interactions: evidence from a multi‐country experiment on Pinus contorta invasion

Evidence of nitrogen fixation in lodgepole pine inoculated with diazotrophic Paenibacillus polymyxa

Botany ◽

10.1139/b2012-044 ◽

2012 ◽

Vol 90 (9) ◽

pp. 891-896 ◽

Cited By ~ 36

Author(s):

Amandeep Bal ◽

Christopher P. Chanway

Keyword(s):

Seedling Growth ◽

Pinus Contorta ◽

Lodgepole Pine ◽

Growth Period ◽

Paenibacillus Polymyxa ◽

N Fixation ◽

Bacterial Strains ◽

Bacterial Inoculation ◽

Foliar N ◽

Negative Effect

Diazotrophic bacteria previously isolated from internal tissues of naturally regenerating lodgepole pine ( Pinus contorta var. latifolia (Dougl.) Engelm.) seedlings were tested for their ability to colonize and fix nitrogen (N) in pine germinants in two experiments. Surface sterilized pine seed was sown in glass tubes containing an autoclaved sand – montmorillonite clay mixture that contained a N-limited nutrient solution labeled with 15N as 0.35 mmol·L–1 Ca(15NO3)2 (5% 15N label). Pine seed was inoculated with one of three of the following bacterial strains: Paenibacillus polymyxa P2b-2R, P. polymyxa P18b-2R, or Dyadobacter fermentans P19a-2R, and seedlings grew for either 27 or 35 weeks. At the end of each plant growth period, P. polymyxa strain P2b-2R was detected in the pine rhizosphere but not inside plant tissues. Pine foliar N concentrations were not affected by bacterial inoculation but significant foliar 15N dilution was observed in seedlings treated with strain P2b-2R (30% and 66%, P < 0.05, in the first and second experiments, respectively). This strain also reduced seedling biomass in both experiments but effects were significant only in the second experiment (36%, P < 0.05). Notwithstanding the negative effect of bacterial inoculation on seedling growth, pine seedlings inoculated with strain P2b-2R derived 30% and 66%, respectively, of their foliar N from bacterial N fixation in two seedling growth experiments. These results demonstrate the possibility that some endophytic diazotrophs facilitate pine seedling growth in N-poor soils.

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Effects of Paenibacillus polymyxa inoculation and different soil nitrogen treatments on lodgepole pine seedling growth

Canadian Journal of Forest Research ◽

10.1139/cjfr-2015-0456 ◽

2016 ◽

Vol 46 (6) ◽

pp. 816-821 ◽

Cited By ~ 18

Author(s):

Henry Yang ◽

Akshit Puri ◽

Kiran Preet Padda ◽

Chris P. Chanway

Keyword(s):

Seedling Growth ◽

Pinus Contorta ◽

Lodgepole Pine ◽

Paenibacillus Polymyxa ◽

Growth Stimulation ◽

Shoot Biomass ◽

N Fixation ◽

Soil N ◽

Greenhouse Study ◽

N Treatment

An endophytic diazotroph, Paenibacillus polymyxa P2b-2R, has been shown to colonize internal tissues of lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) and stimulate seedling growth possibly through nitrogen (N) fixation in an N-limited environment. We evaluated the effects of different soil N concentrations on lodgepole pine seedling growth after inoculation with P2b-2R in a year-long greenhouse study. Seedlings were subjected to monthly application of a nutrient solution containing one of four soil N concentrations as Ca(NO3)2 (5% 15N label): 0.0029, 0.029, 0.29, and 2.9 μmol·L–1, referred to as very low, low, medium, and high soil N treatments, respectively. Foliar 15N atom percent excess and foliar N content values of P2b-2R inoculated seedlings were not significantly different from controls at any N treatment. Similarly, rhizospheric and endophytic population of P2b-2R did not vary significantly across N treatments. Inoculation with P2b-2R resulted in seedling growth inhibition during early stages of the experiment; however, by month 12, inoculated seedlings from the very low soil N treatment had accumulated 56.3% and 46.4% more root and shoot biomass than controls, respectively. These results suggest that pine biomass stimulation by P2b-2R may depend on soil N concentrations and that such growth stimulation may occur without providing significant amounts of fixed N.

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Allelopathic effects of Engelmann spruce bark stilbenes and tannin–stilbene combinations on seed germination and seedling growth of selected conifers

Canadian Journal of Botany ◽

10.1139/b83-031 ◽

1983 ◽

Vol 61 (1) ◽

pp. 279-289 ◽

Cited By ~ 11

Author(s):

Ronald J. Taylor ◽

David C. Shaw

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Pinus Ponderosa ◽

Pinus Contorta ◽

Root Hairs ◽

Root Tip ◽

Engelmann Spruce ◽

Spruce Bark ◽

Allelopathic Effects ◽

Petri Dishes

The allelopathic effects of Engelmann spruce bark and bark extacts on seed germination and seedling growth of several conifer species were examined. Extracts were hydroxystilbenes (isorhapontin and astringin) and condensed tannins. Experiments included the following: (i) seed germination in petri dishes with various concentrations of stilbenes and tannin–stilbenes; (ii) seed germination in petri dishes containing Engelmann spruce bark fragments; (iii) seedling growth in varying mixtures of peat/Engelmann spruce bark, the latter added either before or after seedling establishment; (iv) seedling growth in samples of Engelmann spruce forest soil horizons. In all experiments and in all species there was an allelopathic response to bark extracts. This response was expressed through inhibition of seed germination (seed-coat rupture and radicle emergence), necrotic discoloration and protoplasmic disruption of root-tip cells, suppression of root hairs, and repressed growth in general. Among the conifers tested Pinus ponderosa and Tsuga mertensiana appeared to be the most tolerant to bark extracts, Pinus contorta the most sensitive. Picea engelmannii was moderately sensitive.

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Effect of hexazinone (Pronone?5G)1on the seedling growth and mycorrhizal incidence of Pinus contorta var. latifolia and Picea glauca

Forest Pathology ◽

10.1111/j.1439-0329.1987.tb01027.x ◽

1987 ◽

Vol 17 (4-5) ◽

pp. 282-291 ◽

Cited By ~ 4

Author(s):

P. Chakravarty ◽

S. S. Sidhu

Keyword(s):

Seedling Growth ◽

Picea Glauca ◽

Pinus Contorta

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Forming Impressions of Personality

Social Psychology ◽

10.1027/1864-9335/a000179 ◽

2014 ◽

Vol 45 (3) ◽

pp. 153-163 ◽

Cited By ~ 13

Author(s):

Sanne Nauts ◽

Oliver Langner ◽

Inge Huijsmans ◽

Roos Vonk ◽

Daniël H. J. Wigboldus

Keyword(s):

Impression Formation ◽

Context Dependent

Asch’s seminal research on “Forming Impressions of Personality” (1946) has widely been cited as providing evidence for a primacy-of-warmth effect, suggesting that warmth-related judgments have a stronger influence on impressions of personality than competence-related judgments (e.g., Fiske, Cuddy, & Glick, 2007 ; Wojciszke, 2005 ). Because this effect does not fit with Asch’s Gestalt-view on impression formation and does not readily follow from the data presented in his original paper, the goal of the present study was to critically examine and replicate the studies of Asch’s paper that are most relevant to the primacy-of-warmth effect. We found no evidence for a primacy-of-warmth effect. Instead, the role of warmth was highly context-dependent, and competence was at least as important in shaping impressions as warmth.

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Memorial Consequences of Environmental Context Change in Children and Adults

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000056 ◽

2010 ◽

Vol 57 (6) ◽

pp. 455-461 ◽

Cited By ~ 5

Author(s):

Alp Aslan ◽

Anuscheh Samenieh ◽

Tobias Staudigl ◽

Karl-Heinz T. Bäuml

Keyword(s):

Elementary School ◽

Young Adults ◽

Episodic Memory ◽

Middle Childhood ◽

First Graders ◽

Fourth Graders ◽

Environmental Context ◽

Context Change ◽

Context Dependent

Changing environmental context during encoding can influence episodic memory. This study examined the memorial consequences of environmental context change in children. Kindergartners, first and fourth graders, and young adults studied two lists of items, either in the same room (no context change) or in two different rooms (context change), and subsequently were tested on the two lists in the room in which the second list was encoded. As expected, in adults, the context change impaired recall of the first list and improved recall of the second. Whereas fourth graders showed the same pattern of results as adults, in both kindergartners and first graders no memorial effects of the context change arose. The results indicate that the two effects of environmental context change develop contemporaneously over middle childhood and reach maturity at the end of the elementary school days. The findings are discussed in light of both retrieval-based and encoding-based accounts of context-dependent memory.

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