Source: UNIV OF HAWAII submitted to
INOCULATION OF ARBUSCULAR MYCORRHIZAL FUNGI IN THE NURSERY TO IMPROVE EARLY ESTABLISHMENT OF NATIVE HAWAIIAN TREES
 
PROJECT DIRECTOR: Miyasaka, S. C. Habte, M.
 
PERFORMING ORGANIZATION
TROPICAL PLANT & SOIL SCIENCE
UNIV OF HAWAII
HONOLULU,HI 96822
 
NON TECHNICAL SUMMARY: Hawaii has lost more than half of its endemic bird species, and one major factor is loss of habitat. This project examines inoculation of native tree species with an arbuscular mycorrhizal fungus as a means to improve growth in the nursery, as well as survival and growth in the field.
 
OBJECTIVES: The overall objective of this project is to improve early growth and establishment of native Hawaiian forest tree species through use of beneficial arbuscular mycorrhizal fungi (AMF). Specifically, there are three objectives: 1) To determine the effect of pre-inoculation of koa with the Hawaiian strain of Glomus aggregatum in the nursery on subsequent growth and establishment in the field at Hakalau National Wildlife Refuge (NWR). 2) To isolate AMF that form effective associations with koa or other native tree species under acid soil conditions at the Hakalau NWR. 3) To determine the mycorrhizal dependence of Hawaiian tree species not previously studied, such as olapa (Cheirodendron trigynum), kawau (Ilex anomala), kolea (Myrsine lessertiana), pilo (Coprosma ochracea and C. rhynchocarpa), and naio (Myoporum sandwicense).
 
APPROACH: Objective 1: To determine beneficial effect of AMF on koa. A second field trial will be conducted with improved methods to ensure a greater root colonization by AMF in the greenhouse, more robust koa seedlings, a uniform N level in the nursery medium, and optimal P levels in the field for AMF activity. Koa will be grown in the nursery at Lalamilo station with two mycorrhizal treatments (control and inoculated with G. aggregatum). Seedlings will be grown for 3 to 4 months in the greenhouse at the Lalamilo station, then outplanted in a former pasture area at Hakalau NWR. Two P treatments will be applied at outplanting: 1) P will be applied at the same rate and method of application as the standard fertilization practice (13 g/tree applied in two dibble holes approximately 6 cm from tree); and 2) P will be applied at the rate determined to be optimal for mycorrhizal associations by means of a P sorption isotherm and mixed uniformly into the planting hole. Plots will consist of 40 tree seedlings spaced at approximately 3 m spacing, and the inner 16 trees will be measured. The experiment will follow a randomized complete block design with four treatments and four blocks. Measurements of basal diameter and height will be measured monthly for a year. Root samples will be collected monthly and observed for mycorrhizal colonization of roots. Pinnules will be collected monthly, and their P content will be determined. Analysis of variance will be conducted to determine significant treatment differences in growth, P content, and AMF colonization. Dr. Miyasaka will be responsible for multiplying AMF inoculum and for conducting this second field study. Objective 2: Isolation of AMF adapted to acid soils. Native AMF from rhizosphere soils will be sampled from several healthy stands of koa and mamane at the Hakalau Forest NWR and used to inoculate koa or mamane seedlings in pot studies in the greenhouse at the UH-Manoa campus. Effectiveness of AMF will be determined by pinnule P content and growth over time of seedlings inoculated with various strains of AMF. Spores of effective AMF will be collected and multiplied using corn or sorghum as hosts. Preliminary identification of AMF species will be based on visual observations of spores. Dr. Habte will be responsible for the isolation of effective AMF strains from Hakalau Forest NWR. Objective 3: Mycorrhizal dependence of other Hawaiian tree species. Mycorrhizal dependency will be determined on native Hawaiian tree species that have not been studied earlier, such as olapa, kawau, kolea, pilo, and naio. These tree species are planted as part of a continuing project at the Hakalau NWR. A volcanic ash soil will be sterilized and amended with P with the aid of a P sorption isotherm in order to obtain three levels of soil solution P (0, 0.02, and 0.2 mg P/L). Seedlings will be either inoculated with the Hawaiian strain of Glomus aggregatum or uninoculated (controls). Plants will be harvested and dry weights determined after approximately 3 to 6 months. Mycorrhizal dependency will be calculated. The graduate student, under the supervision of Dr. Habte, will be responsible for these studies.
 
CRIS NUMBER: 0205635 SUBFILE: CRIS
PROJECT NUMBER: HAW00805-M SPONSOR AGENCY: CSREES
PROJECT TYPE: MCINTIRE-STENNIS PROJECT STATUS: TERMINATED MULTI-STATE PROJECT NUMBER: (N/A)
START DATE: Oct 15, 2005 TERMINATION DATE: Sep 30, 2008

GRANT PROGRAM: (N/A)
GRANT PROGRAM AREA: (N/A)

CLASSIFICATION
Knowledge Area (KA)Subject (S)Science (F)Objective (G)Percent
123064010106.350%
123064011026.350%

CLASSIFICATION HEADINGS
KA123 - Management and Sustainability of Forest Resources
S0640 - Tropical forests
F1102 - Mycology
F1010 - Nutrition and metabolism
G6.3 - Protect and Manage Forests and Rangelands


RESEARCH EFFORT CATEGORIES
BASIC 50%
APPLIED 50%
DEVELOPMENTAL (N/A)%

KEYWORDS: koa; acacia koa; olapa; cheirodendron trigynum; kawau; ilex anomala; kolea; myrsine lessertiana; pilo; coprosma ochracea; coprosma rhynchocarpa; naio; myoporum sandwicense; native hawaiian trees; reforestation; arbuscular mycorrhizal fungus; glomus aggregatum; conservation biology

PROGRESS: Oct 1, 2006 TO Sep 30, 2007
OUTPUTS: Pre-inoculation of koa with AMF: Koa (Acacia koa) seedlings were grown in the nursery at the Lalamilo station, using seed from the Hakalau National Wildlife Refuge. Half the seedlings were inoculated with the arbuscular mycorrhizal fungus (AMF), Glomus aggregatum. The seedlings were fertilized weekly with 20 mL of modified Hoagland's solution containing 8 mg P/L for the +AMF treatment and 32 mg P/L for the -AMF treatment. Roots were cleared and stained, and examined for mycorrhizal colonization. At 5 months, seedlings inoculated with AMF had an average of 66% colonization and those grown without inoculation showed no colonization. At the Hakalau National Wildlife Refuge, each planting hole was amended with 24.8 g dolomite to raise the soil pH to 6.0. In addition, 1.06 g P was added per planting hole to achieve an optimal P level for the AMF association. Koa seedlings were outplanted at the Hakalau National Wildlife Refuge on June 28, 2006. Measurements of basal diameter and height were taken monthly. After 6 months of growth, no significant differences were found for either basal diameter or height. Apparently, AMF associations in Acacia koa seedlings did not improve early growth at this planting site. Perhaps, environmental conditions other than low phosphorus could be limiting growth (e.g. cool temperatures). Determine mycorrhizal dependency of kolea: Seed of kolea (Myrsine lessertiana) was acid-scarified in concentrated sulfuric acid for 0, 15, 30, 45, and 60 minutes. After 3 months, seeds germinated after acid-scarification for 15, 30, 45 or 60 minutes. Two germinated seedlings were transferred after 4 months to pots containing 740 g (O.D.) soil from the Honokaa soil series (hydrous, ferrihydritic, isothermic, Acrudoxic Hydrudands). Phosphorus was added to attain P levels in soil solution of 0, 0.02 and 0.2 mg/L. Crude inoculum of Glomus aggregatum was added to the + AMF treatment at 50 g/kg soil (O.D.). The same amount of autoclaved crude inoculum was added to the - AMF treatment. The experimental design followed a randomized complete block design with 6 treatments (3 P levels x 2 AMF treatments) and 4 blocks. Once a week, 50 mL of Hoagland's solution without P was added to each pot. At 8 months after transplanting, the plants were harvested and separated into tops and roots. Fresh weights were determined. Dry weights of tops and roots were determined. At 8 months after transplanting, inoculated seedlings had significantly greater fresh and dry weights of tops and roots. A significant interaction was found between AMF treatment and P level for fresh and dry weight of tops, with the greatest beneficial effect of AMF observed at a soil P level of 0.02 mg/L, a level considered to be optimal for mycorrhizal associations. Difficulties have been encountered in germinating seeds of other native Hawaiian tree species. PARTICIPANTS: Susan C. Miyasaka, University of Hawaii; Mitiku Habte, University of Hawaii; Richard Wass, Hakalau National Wildlife Refuge; Jack Jeffrey, Hakalau National Wildlife Refuge; Baron Horiuchi, Hakalau National Wildlife Refuge; Ayami Shiraishi, University of Hawaii. TARGET AUDIENCES: Hakalau National Wildlife Refuge; Land managers.

IMPACT: 2006-10-01 TO 2007-09-30 Hawaii has lost more than half of its endemic bird species, and one major factor is loss of habitat. To re-establish critical habitats for endangered Hawaiian birds, the Hakalau Forest National Wildlife Refuge (NWR) is engaged in a long-term effort to reforest former pastures using native tree species. Problems in the revegetation of degraded lands with native Hawaiian tree species have been encountered, partly due to the mineral stresses of acid soils. Many of these soils in Hawaii, particularly volcanic ash soils (Andisols), have a high capacity to adsorb or "fix" phosphorus (P) in forms unavailable to plants. Arbuscular mycorrhizal fungi are a low-input solution to the problem of P deficiency, because they are reported to increase the efficiency of P uptake by many plants. An increased understanding of factors controlling this symbiotic relationship will aid in establishment of mycorrhizal seedlings in the nursery that could improve early growth and establishment of native Hawaiian tree species when outplanted to the field.

PUBLICATION INFORMATION: 2006-10-01 TO 2007-09-30
No publications reported this period

PROJECT CONTACT INFORMATION
NAME: Miyasaka, S. C.
PHONE: 808-981-5180
FAX: 808-981-5190