NUTRIENT AND MYCORRHIZAL EFFECTS ON THE ROOT-SHOOT RATIO OF CONTAINERIZED PONDEROSA PINE SEEDLINGS.

Persistent Link:
http://hdl.handle.net/10150/184825
Title:
NUTRIENT AND MYCORRHIZAL EFFECTS ON THE ROOT-SHOOT RATIO OF CONTAINERIZED PONDEROSA PINE SEEDLINGS.
Author:
CORNETT, ZANE J.
Issue Date:
1982
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Attempts at reforestation of many sites in the southwestern United States have repeatedly failed. Experience and research show that moisture stress is the primary cause of seedling mortality. Therefore, it is of utmost importance to produce planting stock for these areas that are as drought tolerant as possible. Seedlings with high ratios of root mass to shoot mass and adequate mycorrhizal infections should be more resistant to harsh conditions than most seedlings currently produced in nurseries and greenhouses. Inferences from other research indicated that the root-shoot ratios of seedlings could be increased solely by decreasing the amount of nitrogen supplied to them. Mycorrhizal formation would also be enhanced by minimal nitrogen levels. Containerized ponderosa pine seedlings (Pinus ponderosa Lawson var. scopulorum Engelm.) were grown in commercial greenhouses at various levels of nitrogen fertilization and treated with several mycorrhizal inoculums. Mycorrhizal treatments significantly increased shoot height and diameter, but no other seedling parameters. The inoculums did not affect the root-shoot ratio or the percent of short roots that became infected. Nitrogen levels significantly affected all parameters measured. As nitrogen concentration increased, shoot height, diameter, and weight increased, while root weight, root-shoot ratios, and mycorrhizal infections decreased. The inverse relationship between fertilizer nitrogen concentration and the resulting root-shoot ratios of the seedlings was linear and highly correlated. Nitrogen and percent mycorrhizal infection was nearly linear and also inversely correlated. The results of this research are immediately applicable to current greenhouse and nursery operations. When stock is to be planted on sites where seedling survival may be compromised by harsh environmental conditions, production methods should be modified to yield seedlings with maximum root-shoot ratios and heavily infected with mycorrhizae.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Ponderosa pine -- Seedlings.; Mycorrhizas.; Plants -- Effect of nitrogen on.; Plant inoculation -- Physiological effect.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Renewable Natural Resources; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleNUTRIENT AND MYCORRHIZAL EFFECTS ON THE ROOT-SHOOT RATIO OF CONTAINERIZED PONDEROSA PINE SEEDLINGS.en_US
dc.creatorCORNETT, ZANE J.en_US
dc.contributor.authorCORNETT, ZANE J.en_US
dc.date.issued1982en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAttempts at reforestation of many sites in the southwestern United States have repeatedly failed. Experience and research show that moisture stress is the primary cause of seedling mortality. Therefore, it is of utmost importance to produce planting stock for these areas that are as drought tolerant as possible. Seedlings with high ratios of root mass to shoot mass and adequate mycorrhizal infections should be more resistant to harsh conditions than most seedlings currently produced in nurseries and greenhouses. Inferences from other research indicated that the root-shoot ratios of seedlings could be increased solely by decreasing the amount of nitrogen supplied to them. Mycorrhizal formation would also be enhanced by minimal nitrogen levels. Containerized ponderosa pine seedlings (Pinus ponderosa Lawson var. scopulorum Engelm.) were grown in commercial greenhouses at various levels of nitrogen fertilization and treated with several mycorrhizal inoculums. Mycorrhizal treatments significantly increased shoot height and diameter, but no other seedling parameters. The inoculums did not affect the root-shoot ratio or the percent of short roots that became infected. Nitrogen levels significantly affected all parameters measured. As nitrogen concentration increased, shoot height, diameter, and weight increased, while root weight, root-shoot ratios, and mycorrhizal infections decreased. The inverse relationship between fertilizer nitrogen concentration and the resulting root-shoot ratios of the seedlings was linear and highly correlated. Nitrogen and percent mycorrhizal infection was nearly linear and also inversely correlated. The results of this research are immediately applicable to current greenhouse and nursery operations. When stock is to be planted on sites where seedling survival may be compromised by harsh environmental conditions, production methods should be modified to yield seedlings with maximum root-shoot ratios and heavily infected with mycorrhizae.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPonderosa pine -- Seedlings.en_US
dc.subjectMycorrhizas.en_US
dc.subjectPlants -- Effect of nitrogen on.en_US
dc.subjectPlant inoculation -- Physiological effect.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineRenewable Natural Resourcesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.committeememberHeidman, L. J.en_US
dc.contributor.committeememberGilbertsonen_US
dc.contributor.committeememberO'Learyen_US
dc.contributor.committeememberPepperen_US
dc.contributor.committeememberStroehleinen_US
dc.identifier.proquest8303385en_US
dc.identifier.oclc683255585en_US
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