Document Type : Research Paper
Authors
1
M.Sc. Graduated, Department of Forestry, Faculty of Natural Resources, Tarbiat Modares University, Noor, I.R. Iran
2
Prof., Department of Forestry, Faculty of Natural Resources, Tarbiat Modares University, Noor, I.R. Iran
3
Assist. Res. Prof.; Mazandaran Agricultural and Natural Resources Research and Education Center, AREEO, Sari, I.R. Iran
Abstract
Cupressus sempervirens var. horizontalis, an ornamental tree, is suitable for wind break, soil conservation, wood production and forms a large part of seedling production in nurseries of Iran. Considering the expected limitations of water resources, the target of this investigation was to study the effect of rhizobacteria Pseudomonas fluorescens on the growth and survival of C. sempervirens seedlings under water deficit. The experiment was carried out with four irrigation periods and two rhizobacteria levels (inoculation and non-inoculation) in a randomized complete block design with three replications. To determine the amount of irrigation water, the field capacity was calculated and the water deficit was given to the plant to the desired moisture content after weighing of the pots. The seedlings in severe water deficit (irrigation period of 12 days) had a survival rate of 95% and higher. Shoot growth and diameter growth were, respectively, reduced by 52.6% and 49.6% in 12-day irrigation compared to 3-day irrigation, but inoculation increased by 14.7% and 14.3% in them, respectively. Regardless of water deficit, root biomass in inoculated seedlings increased by 23.2% compared to the non-inoculated seedlings. Shoot biomass, total biomass and seedling quality index in the period of 9 and 12 days and root volume during the 12-day period decreased, but by inoculation, these variables increased 13.9, 16.8, 20.1 and 25.3, respectively. Overall, although water deficit decreased growth characteristics of C. sempervirens seedlings but it can be concluded that root inoculation with P. fluorescens can be used as a biologic fertilizer to suit the growth and morphological quality of seedlings, even under severe water deficit conditions. This strategy can be useful for producing proper seedlings of C. sempervirens in nurseries facing water constraints.
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