نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 گروه گیاهپزشکی دانشگاه علوم کشاورزی و منابع طبیعی گرگان
2 بخش تحقیقات حفاظت و حمایت موسسه تحقیقات جنگل ها و مراتع کشور
3 گروه گیاهپزشکی/ دانشگاه بیرجند
4 بخش حفاظت و حمایت/ موسسه تحقیقات جنگل ها و مراتع کشور
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and purpose: Increasing need for wood and the other hand declinig wood resources have coused desire for afforestation with fast gowing species such as poplars, but weter deficit and cytosporal cankers on poplar species have become to important limiting factors of poplar cultivation in some parts of Iran. Ectomycorrhizal fungi have significant effect in improving the water status of plants, increasing the survival and growth of plants under stress.. The purpose of this research is investigation the effect of Laccaria bicolor on some morphological and physiological characteristics of poplar seedlings under drought stress and cytosporal canker.
Materials and methods: This research was done in factorial form in a completely randomized design with 5 replications. The test factors included the biological factor in two levels (without mycorrhiza and with mycorrhiza) and the stress factor in three levels (no stress, drought stress and Cytospora stress). Inoculation of ectomycorrhizal fungus to poplar seedlings was done 14 weeks after the cuttings were cultivated in the pot and height of the seedlings reached to 50 cm.. Isolation and identification of the fungus causing cytosporal canker was done morphologically and molecularly and it was inoculated into poplar seedlings( after ectomycorrhizal establishment). Drought stress was done by reducing irrigation water based on the agricultural capacity of plants. Measurement of growth characteristics, physiological and enzymatic reactions of plants under stress and non-estress conditions were evaluated in different treatments.
Results: The level of catalase, superoxide dismutase and peroxidase significantly increased in mycorrhizae- drought and mycorrhizae – Cytospora seedlings and had a significant difference of 1% with control seedlings under stress. The level of malondialdehyde (MDA) in the mycorrhizal seedlings under stress increased less than the control seedlings under stress and they have a significant difference with each other at the 1% level. Using of ectomycorrhizal fungus L. bicolor improves the growth characteristics of poplar seedlings, the amount of leaf area, leaf fresh and dry weight, root fresh and dry weight, stem fresh and dry weight and stem height have significant differences with seedlings without symbiosis. The stem diameter in symbiosis seedlings with and the control treatment had no significant difference. Ectomycorrhizal symbiosis has led to an increase in photosynthesis, stomata conductance, intercellular carbon dioxide and transpiration in the symbiotic seedlings compared to the control treatment. In the drought and cytospora stress, plants without symbiosis had a lower performance in photosynthesis, transpiration, and stomatal conductance, which led to a decrease in growth in these treatments.
Conclusion: In this study, Cytospora chrysosperma was identified as the causative agent of cytosporal canker. Findings of this research showed that the ectomycorrhizal fungus Laccaria bicolor was able to create symbiosis with P.alba in greenhouse conditions. This symbiosis has increased growth, improved plant physiology, and increased plant resistance in plants with symbiosis compared to seedlings without symbiosis under drought and cytospora canker. Therefore, considering the improvement of the water condition, increase growth and biomass, and modification of the physiological characteristics of the inoculated plants with ectomycorrhizal fungi compared to the control, Establishing this ectomycorrhizal interaction can be introduced as a new strategy to increase success of seedlings in poplar plantations for wood cultivation.
کلیدواژه‌ها [English]
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