توانایی جنس‌های قارچ مایکوریزا آربسکولار و اندوفیت برای بهبود تحمل به شوری در نخود (.cicer arietinum l)

شرایط نامطلوب محیطی نظیر تنش‌های غیر زیستی، تولید محصولات زراعی را تحت تاثیر قرار داده و در این میان تنش شوری از مهم‌ترین عواملی است که سبب کاهش عملکرد محصول در مناطق خشک و نیمه خشک می‌شود. به‌منظور بهبود تحمل به شوری در نخود با استفاده از گونه‌های قارچ میکوریزا، در سال 1395 آزمایشی به‌صورت فاکتوریل در قالب طرح بلوک کامل تصادفی با سه تکرار در شرایط گلخانه در دانشگاه فردوسی مشهد اجرا شد. تیمارهای تنش شوری شامل چهار سطح (0.5 (آب معمولی)، 3، 6 و 9 دسی‌زیمنس بر متر) و گونه‌های مایکوریزا در سه سطح (توده بومی، piriformospora indica به‌عنوان اندوفیت (شبه مایکوریزا) و gigospera margarita) بودند. نتایج نشان داد که شوری موجب کاهش صفاتی چون تعداد شاخه فرعی، وزن خشک بوته، ارتفاع بوته، تعداد برگ، محتوای نسبی آب برگ، شاخص پایداری غشاء، هدایت روزنه‌ای، شاخص سبزینگی، حجم ریشه، طول ریشه، وزن خشک ریشه و درصد کلنیزاسیون شد. در میان گونه‌های مایکوریزا، گونه piriformospora indica نسبت به سایر گونه‌ها تاثیر بیشتری بر ویژگی‌های مورد ارزیابی داشت. به طوری که کاربرد قارچ piriformospora indica موجب افزایش ارتفاع بوته به میزان 7/12 درصد نسبت به توده بومی گردید. میزان افزایش وزن خشک اندام هوایی در سطوح شاهد، سه، شش و 9 دسی زیمنس بر متر شوری در تیمار کاربرد قارچ piriformospora indica نسبت به تیمار توده بومی به ترتیب 19.6، 29.9، 26.1 و 24.4 درصد و نسبت به کاربرد قارچ gigospera margarita به ترتیب 66.8، 58.8، 87.5 و 69.3 درصد بود. تیمار شاهد به همراه مصرف شبه مایکوریزا گونه piriformospora indica بیشترین میزان کلنیزاسیون را (54.7 درصد) به خود اختصاص داد. به‌طورکلی استفاده از گونه‌های مایکوریزا موجب کاهش اثرات منفی تنش شوری شد که در این میان گونه piriformospora indica و سپس توده بومی واکنش بهتری نشان دادند.

Ability of mycorrhiza arbuscular and endophyte species to improve salinity tolerance in chickpea (Cicer arietinum L.)

IntroductionLow yield and instability, is one of the most important issues in chickpea cultivation. The adverse environmental conditions have affected the crop yield; in this regard, one of the most important factors is salinity stress that reduces crop yield. Meanwhile, microorganisms have a high ability to mitigation the adverse effects of salinity. In addition, the coexistence of beneficial bacteria and fungi creates a potential for a decrease of salinity stress impacts on plants. Mycorrhizal fungi belonging to the branch Glomeromycota, one of the oldest living organisms introduced to coexist with plants on land and in salinity. These fungi are widely found in saline soils. Research has shown that mycorrhizal arbuscular fungi increase salinity tolerance and prevent yield loss. Studies have shown that the coexistence of mycorrhizal arbuscular fungi with crop roots increases the activity of antioxidant enzymes and this expansion of activity to the plant helps to reduce the effects of salinity stress. With regard to the beneficial effects of mycorrhizal fungi on reducing salinity effects in crops, this study aimed to evaluate salt tolerance in chickpea using native mycorrhizal fungi to improve soil properties and its sustainable production under saline conditions.Materials and MethodsThis study was performed in 2016 as factorial based on completely randomized block design with three replications in the research glasshouse of the College of Agriculture, Ferdowsi University of Mashhad. Salinity stress treatments included four levels (tap water [control], 6, 6 and 9 dS.m1 sodium chloride) and mycorrhiza species at three levels (native mass, Piriformospora indica as endophyte, and Gigospera margareta). Four weeks after applying salt stress, maximum quantum efficiency of PSII photochemistry (F’v/F’m) II, stomatal conductance, SPAD index, relative water content (RWC) of leaves, and membrane stability index in the youngest fully expanded leaf were measured. In addition, morphological traits, including plant height, lowest branch height, number of branch number, and number of leaves per plant were measured. At the end of the experiment, the shoot fresh and dry weight, length, volume and dry weight of root were measured, finally root colonization was assessed.Results and DiscussionThe maximum quantum efficiency of PSII photochemistry (F’v/F’m) affected by different levels of salinity and mycorrhiza application. The highest and lowest maximum quantum efficiency of PSII photochemistry (F’v/F’m) levels were related to 9 dS.m1 salinity treatment with mycorrhiza Piriformospora indica and control treatment with Gigospera margareta species, the difference between which was 4.5 times. In addition, the highest amount of gas exchange was observed in the Piriformospora indica species. The highest SPAD index was related to treatment with Piriformospora indica fungi in nonstress conditions and the highest salinity stress level. Moreover, application of Piriformospora indica fungal species increased RWC by 4.54% and 9.20%, compared to the use of mycorrhiza native mass and Gigospera margareta species, respectively. Application of Piriformospora indica showed superiority in membrane stability index relative to Gigaspora margareta in all treatments of salinity stress, with the exception of 9 dS.m1 treatment. However, no significant difference was observed between mycorrhiza treatments in 9 dS.m1 of salinity stress. Root inoculation with Piriformospora indica increased plant height by 12.7%, compared to mycorrhiza native mass. At all levels of salinity stress, Piriformospora indica increased shoot fresh weight, compared to native mass and Gigospera margareta treatments. Furthermore, the least and highest decrease in root length was observed in Piriformospora indica and Gigospera margareta treatments, respectively. Among mycorrhiza fungi treatments, Piriformospora indica produced the highest root volume, compared to native mass and Gigospera margareta treatments with a difference of 10.9% and 36.4% between them. In addition, in non saline treatment with Piriformospora indica had the highest percentage of root colonization (54.66).ConclusionAccording to the results of the study, most traits evaluated in the study were affected by increased intensity of salinity stress. In addition, increased salinity had a negative impact on root development due to increased soil osmotic potential and toxicity, which ultimately reduced plant growth. Moreover, mycorrhiza inoculation had a significant, positive effect on the photosynthetic system of photosystem II, shoot and root dry weight, ratio of shoot to root, root length and percentage of colonization, root volume, root fresh weight, RWC and membrane stability index. Inoculation of commercial species of mycorrhiza under salt stress increased plant salinity tolerance.