تأثير تنش‌ هاي شوري و خشكي بر رشد و جوانه زني زيره سياه (Bunium persicum Boiss)

Effect of Salinity and Drought Stresses on Germination Stage and Growth of Black Cumin (Bunium Persicum Boiss)

گياهان مرتعي از اهميت و نقش ويژه اي در صنايع دارويي برخوردارند. كاهش كمي و كيفي منابع آب همراه با شوري خاك از مهمترين عوامل بازدارنده در تكثير و رشد گياهان بشمار مي رود. لذا اين امر نيازمند شناخت و بررسي شرايط مطلوب رشد گياهان مي‌ باشد. زيره سياه (Bunium persicum Boiss) يكي از گياهان مهم دارويي ايران است كه داراي خواص ضد نفخ، مقوي معده، اشتهاآور و مدر بودن مي باشد. تنش‌ هاي شوري و خشكي از عوامل مهم كاهش عملكرد اين گياه محسوب مي‌ شود. به‌‌ منظور بررسي تأثير تنش‌هاي شوري و خشكي دو آزمايش به‌‌ صورت مجزا در قالب طرح كاملاً تصادفي با چهار تكرار بر روي بذر گونه زيره سياه انجام شد. تنش خشكي شامل پنج سطح (شاهد، 0/2- ، 0/4- ، 0/6- و 0/8-) مگاپاسكال ايجاد شده توسط محلول پلي‌ اتيلن‌ گليكول 6000 و تنش شوري نيز در شش سطح (شاهد، 50، 100، 150، 200- و dS.m 1300) اعمال شد. بعد از اعمال تيمارها شمارش بذور جوانه‌ زده به‌ صورت روزانه انجام شد و درصد و سرعت جوانه‌ زني، طول ريشه‌ چه، ساقه‌ چه و گياه‌ چه و نيز ضريب آلومتري و بنيه بذر تعيين گرديد. نتايج آناليز آماري نشان داد كه تنش‌ هاي خشكي و شوري، درصد و سرعت جوانه‌ زني، شاخص بنيه‌ ي بذر، ضريب آلومتري، طول ساقه‌ چه، ريشه‌ چه و گياه‌ چه را به‌ طور معني‌ داري كاهش مي‌ دهند، به‌ طوري‌ كه جوانه‌ زني در تيمار 06/- مگاپاسكال خشكي به‌ طور كامل متوقف شد. داده‌ هاي تحقيق نشان مي‌ دهد كه زيره سياه گونه‌ اي حساس نسبت به تنش‌ هاي محيطي از جمله خشكي و شوري در مراحل ابتدايي جوانه‌ زني و رشد بذور مي‌ باشد.

Introduction Range plants have important and crucial roles in medicinal industry andtogether with scarcity and low quality of the water and soil resources, prevent a quick recovery of the soil plant covering. Because of these restrictions, it is important to consider the use of salt and drought tolerant species for plantation and to preserve plant cover. In this sense, the use of native species such as black cumin (Bunium persicum Boiss) may be of interest due to their medicinal characteristics and potential ability to adapt to adverse conditions (dry and saline conditions). Black cumin (B. persicum) as a medicinal plant plays a vital role in Iranian medicine so there is a need to know about the factors affecting their growth and propagation. Materials and Methods To investigate the effects of drought and salt stresses on germination and growth in black cumin two separate experiments were conducted. Drought stress was applied through incubation in four different concentrations of PEG 6000 that provide solutions with water potentials ranging from -0.2 to -0.8 MPa (including control and four levels of dryness). Salinity treatments (including control and four levels of salinity) were prepared by adding molar concentrations of NaCl to provide a range of salinity from 50 to 300 mM. Germination percentage and speed was calculated by computation of germinated seeds every day. Growth parameters (rootlet, shoot and seedling length total), allometric index and seed vigority were obtained accordingly. Results and Discussion Seeds under both drought and salt stress showed significant reduction in germination percentage, germination rate, radicle length, plumule length, and alometric and seed vigor indices. This trend was much pronounced under high levels of NaCl and low levels of water potentials, so that germination at Ψs = -0.6 MP was completely stopped. Conclusions Assessment of drought and salt stresses on germination and growth in black cumin is very important in the management of its planting. With increasing salinity