اثرات نيتريك اكسايد بر برخي از صفات فيزيولوژيك در سه گونه از مركبات در شرايط كم آبي

Effects of NO on some physiological characteristics in three species of citrus in water deficit condition

به منظور بررسي تاثير نيتريك­ اكسايد بر برخي صفات فيزيولوژيكي مركبات تحت شرايط كم آبي، آزمايشي به صورت فاكتوريل در قالب طرح بلوك­هاي كامل تصادفي بر روي 3 گونه از مركبات شامل: پونسيروس، سيتروملو و سيترنج در 3 سطح تنش خشكي (30، 60 و 100 درصد ظرفيت مزرعه­ اي)، 3 سطح سديم نيتروپروسايد (آزادكننده­ ي نيتريك اكسايد) (0، 0/5 و 1 ميلي­ مولار) و در 3 تكرار طراحي گرديد. شاخص­ هاي فيزيولوژيكي از جمله كلروفيل فلورسنس، هدايت روزنه­ اي، پتانسيل آب برگ و محتوي نسبي آب برگ (RWC) اندازه ­گيري شد. شاخص ­هاي بيوشيميايي از جمله فعّاليت آنتي­اكسيداني كل (DPPH)، فنل كل و مالون­ دي ­آلدئيد مورد ارزيابي قرار گرفت. نتايج حاصل از اين آزمايش نشان داد كه تنش خشكي باعث كاهش معني­ داري در مقادير پتانسيل آب برگ، هدايت روزنه­ اي، محتوي نسبي آب برگ (RWC) و Fv/Fm شده است. شاخص­ هاي بيوشيميايي مثل DPPH، فنل كل و مالون­دي آلدئيد در اثر تنش خشكي افزايش معني ­داري نشان دادند. كاربرد سديم نيترو پروسايد در اين تحقيق نشان داد كه اين ماده نقش تعديل­ كنندگي در تنش خشكي داشته و اثرات آن را كاهش داده است. نتايج نشان داد كه غلظت 1 ميلي مولار اين ماده تأثير بيشتري در تعديل اثرات تنش داشته است.

Most plants encounter with different environmental stresses during their life cycle. Water deficit is one of the stresses that negatively affect the growth and yield of many agricultural crops such as members of citrus family. Higher plants developed several physiological and biochemical adaptation systems that give them a chance to survive and let them to escape from water deficit stress. In this research the effect of Nitric Oxide, as a stress modulator, on citrus plants was investigated. A trial was conducted as factorial with randomized complete blocks design in three replications on three species of citrus including Poncirus, Swingle citrumelo and Carrizo citrange. There were also drought stress treatments in three levels (FC, 30% FC and 60% FC) and Sodium nitroprusside treatments, as a NO releasing compound, in three levels (0, 0.5 and 1 mM). Some physiological factors such as chlorophyll fluorescence, stomatal conductance, leaf water potential and leaf relative water content were measured. Also, some biochemical factors such as DPPH and the contents of phenols and malondialdehyde were investigated. The results showed that drought stress, decreased leaf water potential, stomatal conductance, relative water content and Fv/Fm significantly. Some biochemical factors such as DPPH, phenols and malondialdehyde activity increased during drought stress. Application of sodium nitroprusside, modulated the destructive effects of drought stress specially with the concentration of 1 mM.