بررسی کارآیی فسفر و شاخص مقاومت به تنش خشکی و شوری در پایه‌های پسته همزیست‌شده با قارچ مایکوریزا آربسکولار

تنش‌های خشکی و شوری از مهم‌ترین عوامل محدودکننده رشد و کارآیی گیاهان هستند. از این‌رو پژوهشی جهت بررسی اثر تلقیح پایه‌های پسته با یک ایزوله از قارچ مایکوریزا آربسکولار بر ویژگی‌های رشدی، کارآیی استفاده از فسفر و مقاومت به تنش پایه‌ها در دانشگاه شهرکرد در سال 96-1395 اجرا گردید. دو آزمایش جداگانه به‌صورت فاکتوریل با سه فاکتور بر پایه طرح کاملا تصادفی در سه تکرار انجام شد. فاکتور اول در هردو آزمایش پایه‌های پسته در چهار سطح، شامل بادامی‌ریز زرند، قزوینی، سرخس و هیبرید ucb1، فاکتور دوم در هردو آزمایش مایکوریزا در دو سطح شامل عدم تلقیح و تلقیح پایه‌ها و فاکتور سوم در آزمایش اول تنش خشکی (آبیاری به میزان 100درصد ظرفیت گلدانی به‌عنوان شاهد، 80، 60 و 40 درصد ظرفیت گلدانی) و در آزمایش دوم تنش شوری (0.91 به‌عنوان شاهد، 7.57، 16.12 و 24.63 دسی‌زیمنس برمتر) بود. دانهال‌های پسته به مدت 60 روز تحت تنش قرار داشتند. مایکوریزا باعث افزایش وزن تر ریشه، ساقه و برگ در هردو تنش و نسبت سطح برگ و سطح مخصوص برگ در تنش شوری گردید. گیاهان تلقیح‌شده با مایکوریزا کارآیی استفاده از فسفر کمتر و تحمل بیشتری در برابر تنش‌های خشکی و شوری داشتند. شاخص‌های رویشی و کارآیی استفاده از فسفر ریشه، برگ و کل گیاه در اثر هر دو تنش خشکی و شوری کاهش یافت. واکنش چهار پایه استفاده شده در این آزمایش به مایکوریزا و تنش‌های خشکی و شوری متفاوت بود. نتایج این تحقیق نشان داد پایه‌های سرخس و ucb1 به‌ترتیب از نظر تحمل به تنش خشکی و شوری بهتر از دو پایه دیگر بودند.

Investigation of Phosphorus Use Efficiency and Drought and Salinity Stress Resistance Index in Pistachio Rootstocks Coexisted with Mycorrhiza Arbuscular

AbstractIntroductionEnvironmental stresses are serious threats to agricultural production. Abiotic stress too is a serious threat to agricultural products. Pistachio is one of the most important agricultural products in Iran and United States and is grown in other countries as well. Pistachio has good yields in rain fed condition and increases the flush and quality of yield by irrigation. Arbuscular mycorrhizal fungi (AMF) are among the most useful microorganisms in soil, and most plants can become symbiotic with mycorrhiza, that help improve nutritional conditions and other functions such as photosynthesis and osmotic regulation under stress conditions. Materials and MethodsAMF, (Funneliformis mosseae) were grown using corn (Zea mays). Four pistachio rootstocks in symbiosis with mycorrhiza were subjected to drought and salinity stress in two separate experiments. Plants were divided randomly into three treatments (three replications and 6 plants per treatment), Treatments included drought, salinity, mycorrhiza and rootstock (In Shahrekord University 32 °21 N 50° 49 E, 201718). At the end of the experiment, the plants were harvested. Then all parts of the plant, including roots, shoots and leaves, were separated and weighted. The amount of phosphorus was measured using a spectrophotometer (UVVis Spectrometer) at a wavelength of 470 nm (Olsen et al., 1954). Data were evaluated by Threeway analysis of variance (ANOVA) with SPSS 25.0.0. Results and DiscussionThe rootstock biomass in this experiment were influenced by different treatments (mycorrhiza, rootstock type and stress). P content of both leaves and root tissues of pistachio rootstocks was affected by both drought and salinity stress (Not shown in the data). Mycorrhiza increased root, stem and leaf fresh weight under drought and salinity stress and leaf area ratio and specific leaf area under salinity stress. Mycorrhizainoculated plants had lower phosphorus use efficiency and more tolerance to drought and salinity stresses. Growth indices and phosphorus use efficiency of root, leaf and total, decreased under both drought and salinity stresses. The Sarakhs rootstock was more salinitysensitive than other rootstocks. In this research, pistachio rootstocks showed differences in biomass and biomass reduced under salinity and drought stress. Biomass reductions under abiotic stress (drought and salinity stress) conditions in previous studies on almond, peaches, olives, apple and pistachio fruit trees are also reported here. Biomass was higher in +M rootstocks, which could have been due to effects of mycorrhizal symbiosis on P absorption. The difference between rootstocks is related to rootstock absorption capacitywhich has to do with root condition. Therefore, rootstocks with better roots growth may develope root survival under stress condition. They can also be better in mineral uptake and more tolerant to stress statue, because the ability of plants to withstand stresses depends to a large extent on roots. ConclusionThe use of beneficial soil microorganisms is one of the best strategies contributing to sustainable agriculture and the environment. Among the most beneficial soil microorganisms with which plants may establish a symbiotic relationship are arbuscular mycorrhizal fungi (AMF). AMF can improve soil physicochemical properties that generate plant growth and elevate the status of plants in terms of water and mineral nutrition, leading to improved plant growth maintenance. Based on these findings, AMF in symbiosis with pistachio rootstocks helped increase drought and salinity stress tolerance.