NORTH AMERICAN SYMBIOTIC

12th North American Symbiotic Nitrogen Fixation Conference PROGRAM AND ABSTRACTS HOSTED BY: DEPARTMENT OF GENETICS IOWA STATE UNIVERSITY AMES, IOWA JULY 30 - AUGUST 3, 1989 The effect of new growth biostimulent on acetylene reduction in nodulated seedlings of Alnus acuminata. R.O. Russo* and G.P. Berlyn, Yale University, School of Forestry and Environmental Studies, New Haven, CT 06511. USA. Alnus acuminata is an actinorhizal tree, commonly associated with pastures on upland areas of Costa Rica, Colombia and Venezuela. The objective of this study was to compare the acetylene reduction response of Alnus acuminata seedlings to a treatment with an organic biostimulant, viz. ROOTS® (Soilizer Corp., New Haven, CT.) composed of humic acids, marine algae extracts and intermediary metabolites. It has previously been shown in our laboratory that this biostixnulant increases growth, enhances nutrient and water uptake, increases chlorophyll synthesis and promotes wood formation. Alnus acuminata seedlings grown in a greenhouse mix, were inoculated with a crushed nodule suspension from seedlings originally inoculated with nodules collected in Costa Rica. After 120 days, acetylene reduction values were measured using the continuous flow procedure. The plants were then harvested and leaves, stem, root, and nodule biomass were evaluated. Differences in timol of ethylene per gram of nodule dry weight per hour were significant (P<0.0l) in favor of treated seedlings (68.7 vs. 39.6 ~.imol/g drwt/hr). Biomass variables and analysis of growth of seedlings in both groups are discussed.

Alnus acuminata is an actinorhizal tree, commonly associated with pastures on upland areas of Costa Rica, Colombia and Venezuela. The objective of this study was to compare the acetylene reduction response of Alnus acuminata seedlings to a treatment with an organic biostimulant, viz. ROOTS® (Soilizer Corp., New Haven, CT.) composed of humic acids, marine algae extracts and intermediary metabolites. It has previously been shown in our laboratory that this biostixnulant increases growth, enhances nutrient and water uptake, increases chlorophyll synthesis and promotes wood formation. Alnus acuminata seedlings grown in a greenhouse mix, were inoculated with a crushed nodule suspension from seedlings originally inoculated with nodules collected in Costa Rica. After 120 days, acetylene reduction values were measured using the continuous flow procedure. The plants were then harvested and leaves, stem, root, and nodule biomass were evaluated. Differences in timol of ethylene per gram of nodule dry weight per hour were significant (P<0.0l) in favor of treated seedlings (68.7 vs. 39.6 ~.imol/g drwt/hr). Biomass variables and analysis of growth of seedlings in both groups are discussed.