پديد آورندگان :
فاطمي نژاد، دانشكاه آزاد اسلامي واحد بروجرود - دانشكده تحصيلات تكميلي - گروه زيست شناسي , لاري يزدي، حسين دانشكاه آزاد اسلامي واحد بروجرود - دانشكده تحصيلات تكميلي - گروه زيست شناسي , رفيعي، مسعود مركز تحقيقات و آموزش كشاورزي و منابع طبيعي استان لرستان - بخش تحقيقات اصلاح و تهيه نهال و بذر
كليدواژه :
كلروفيل a , كلروفيل b , تنظيم اسمزي , عملكرد دانه
چكيده فارسي :
ريزگرد مشكل نوظهوري است كه همراه با تنش خشكي مناطقي از غرب و جنوب كشور را درگير كرده است. به منظور بررسي تأثير اين دو عامل بر خصوصيات فيزيولوژيكي گياه ماش (Vigna radiata L.)، آزمايشي بصورت كرت‌هاي خرد شده بر پايه طرح بلوك‌هاي كامل تصادفي با 4 تكرار در تابستان سال زراعي 1394 در مركز تحقيقات و آموزش كشاورزي و منابع طبيعي لرستان انجام شد. عامل تنش خشكي از طريق آبياري پس از 70 (آبياري نرمال)، 80، 90 و 100 ميلي‌متر تبخير از تشتك تبخير كلاس الف در كرت-هاي اصلي و عامل شبيه‌سازي ريزگرد شامل سه سطح شاهد (بدون ريزگرد) و كاربرد 50 و 100 ميلي‌گرم در متر مكعب ريزگرد در كرت‌هاي فرعي قرار گرفت. نتايج نشان داد كه ميزان كلروفيلa تحت تأثير هم‌افزائي افزايش غلظت ريزگرد و تشديد تنش خشكي بطور معني‌داري كاهش يافت. تنش خشكي همچنين باعث كاهش معني‌داري در كلروفيل‌هاي b وa+b و همچنين قندها و پروتئين‌هاي محلول برگ گرديد. رابطه خطي معني‌دار و منفي ميان تنش خشكي با عملكرد دانه و مثبت ميان تنش خشكي با محتوي پرولين برگ در گياه ماش مشاهده شد. درمجموع گياه ماش علي‌رغم كاهش عملكرد دانه، سعي در تعديل تنش خشكي از طريق تنظيم اسمزي با افزايش اسموليت‌هاي پرولين و قندهاي محلول نمود و واكنش تقابلي به ريزگرد نشان نداد.
چكيده لاتين :
Introduction: Amongst legumes, mungbean (Vigna radiata L.) is considered to be particularly important in agricultural production under unfavorable growing conditions due to its short growth period. Aerosols are principal air pollutants that can greatly impact human health and plant development. This natural phenomenon, which mainly occurs in Iraq and Iran`s western regions, has exacerbated in recent years and caused a lot of damage (Marsafari, 2011). The occurrence of haze and accumulation of aerosol particles in the air can cause environmental disturbance, leading to reduced direct and indirect photosynthetic active radiation. Abiotic stresses, in particular, water shortage pose immense challenges to crop production and can decrease crop yields by 50 % worldwide. Water deficit has negative impact on growth, development and production of legumes, which may result in decreased chlorophyll a and b and increased proline content of leaf (Gholdani, 2012). Since in addition to water scarcity, aerosol phenomenon coincides with the mungbean growth period in the region, the objective of this study was to evaluate the effects of aerosol practices and drought stress on mungbean photosynthetic pigments, nitrogen compounds, soluble sugars and grain yield. Materials and Methods: The research was conducted to investigate the effect of drought and aerosol stresses on physiological traits of mungbean (Vigna radiata L.) at Lorestan Agricultural and Natural Resources Research and Education Center in 2015. The experimental location lies at latitude 33° and 29’ N, longitude 48° and 18’ E, and an altitude of 1195 m above sea level. Before the beginning of the experiment, soil samples were taken in order to determine the physical and chemical soil properties. A split plot design based on RCBD was used with four replications. The main plots were allocated to four different irrigation regimes: watering after 70 (I70) (well irrigated treatment), 80 (I80), 90 (I90) and 100 (I100) mm evaporation from pan class A. The subplots were assigned to three levels of aerosols derived from clay soil source )control treatment with no aerosol application (A0), 50 (A50) and 100 (A100) mg m-3 aerosol particles( . Chlorophyll a, chlorophyll b, chlorophyll a + b, soluble sugars and protein content in leaves were measured at flowering period and grain yield was measured at harvesting time. The data were statistically analyzed using the MSTAT-C and SAS software. Comparison of means was performed using the Least Significant Difference test at 5% probability level. Results and Discussion: The results showed that chlorophyll a, chlorophyll b and chlorophyll a+b were significantly affected by drought stress. Aerosol only affected chlorophyll a. Also, the interaction effect of drought stress and aerosol application was significant on chlorophyll a. The highest amount of chlorophyll a (0.015 mg g-1 FW) in leaves was achieved by normal irrigation (I70) at different levels of aerosol treatment. Chlorophyll b and chlorophyll a + b were significantly reduced by drought stress. As drought stress was intensified, the difference in leaf chlorophyll content under different levels of aerosol increased so that when the mungbean plant was watered at I100, its chlorophyll a content decreased from 0.008 mg g-1 FW with no aerosol application to 0.0046 mg g-1 FW under A100 mg m-3 treatment. Soluble leaf sugar concentration was not affected by aerosol application but was significantly impacted by water deficit treatment. Sugar content increased from 1.86 mg g-1 FW at I70 to 4.62 mg g-1 FW at I100. Plants, when encountering water stress, undergo a series of physiological changes to respond to the stress. Accumulation of soluble substances in cells is a way by which different plants such as legumes can maintain their turgor under water-limited conditions (Sanchez et al., 2003). Protein content was also significantly affected by drought stress and decreased from 0.15 at I70 to 0.05 mg g-1 DW at I100. There was a significant and negative linear relationship between drought stress and grain yield, but a significant and positive linear relationship was detected between drought stress and leaf proline. Conclusion In total, our results indicated that aerosol and drought stress had synergistic effect on chlorophyll a destruction. Chlorophyll b and chlorophyll a+b contents, leaf soluble sugar and protein concentrations experienced conspicuous decline with intensification of water stress.
