بررسي ميزان زنده ماني و اثرتيمارهاي متفاوت شكستن خواب فيزيكي بر جوانه زني بذر دو گونه درختي (نمدار و اقاقيا)

Investigation of viability rate and the effects of different breaking treatments of physical dormancy on seed germination of two tree species (Basswood and Black locust)

دو گونه جنگلي نمدار و اقاقيا از جمله گونه هاي جنگلي به شمار مي آيند كه به دليل دارا بودن پوسته بذر بسيار سخت و محكم داراي خواب بذر(Seed Dormancy) مي باشند. جهت حذف اين پوسته (شكستن خواب بذر) و تسهيل فرآيند جوانه زني بذرهاي اين دو گونه و نيز بررسي تاثير تيمارهاي خراشدهي بر روي ميزان جوانه زني، بذور اين دو گونه در سال 1393 از نهالستان قرق واقع در شهرستان گرگان تهيه گرديد. جهت تعيين ميزان زنده ماني بذرها، در ابتدا آزمون تترازوليوم انجام شد. سپس جهت بررسي تيمارهاي متفاوت شكستن خواب فيزيكي (خراش­دهي)، تيمارهاي آب جوش(100 درجه با مدت زمان 1 دقيقه)، آب اكسيژنه(1% با مدت زمان 40 دقيقه)، اسيد سولفوريك (30 درصد با مدت زمان ده دقيقه) و شاهد بر روي بذرها اعمال گرديد. آزمايش ها در آزمايشگاه دانشكده كويرشناسي دانشگاه سمنان انجام شد. نتايج آزمون تترا زوليوم نشان داد كه گونه هاي نمدار و اقاقيا به ترتيب داراي 57.25 و 78.3 درصد زنده ماني بودند. بالاترين ميزان جوانه زني در مورد بذر نمدار، تيمار آب اكسيژنه بيشترين با ميزان جوانه زني (38 % ) و در مورد بذر اقاقيا تيمار آب جوش با بيشترين ميزان جوانه زني (66.69) مشاهده گرديد. از آنجايي كه بذر اقاقيا با وجود دارا بودن پوسته بسيار سخت از جوانه زني بهتري نسبت به گونه نمدار برخوردار است، مي توان نتيجه گرفت كه به جز پوسته سخت عوامل ديگري نيز در جوانه زني بذر گونه نمدار دخيل هستند.

Basswood(Tilia begonifolia) and Blacklocust (Robinia pseudoacacia) are two forest trees with seed dormancy due to very hard seed coat. Seeds of two species were collected from Ghorogh nursery in Gorgan province to remove seed coat (breaking seed dormancy) and simplify germniation process and examine the effects of scarification on their germination and viability in 2014.The tetrazolium test was done to measure the seed vitatlity.Then the seed germination rate was tested using hot water (100°C for 1 min. ), H2O2 (1 % for 10 min.), H2SO4 (30 % for 10 min.) and control treatments. The experiment was done in the laboratory of the Faculty of Desert Study (Semnan university). The results of tetrazolium test showed that Tilia begonifolia and Robiniapseudoacacia have 57.25 and 78.30 percent of viability, respectively. The highest rates of seed germination of Tilia begonifolia and Robinia pseudoacacia were observed in H2O2 (%38) and hot water (%66.69) treatments, respectively. As the seeds of Robinia pseudoacacia have higher seed germination than Tilia begonifolia despite of having hard seed coat, it can be concluded that other factors except of hard seed coat can affect seed germination of Tilia begonifolia. Basswood(Tilia begonifolia) and Blacklocust (Robinia pseudoacacia) are two forest trees with seed dormancy due to very hard seed coat. Seeds of two species were collected from Ghorogh nursery in Gorgan province to remove seed coat (breaking seed dormancy) and simplify germniation process and examine the effects of scarification on their germination and viability in 2014.The tetrazolium test was done to measure the seed vitatlity.Then the seed germination rate was tested using hot water (100°C for 1 min. ), H2O2 (1 % for 10 min.), H2SO4 (30 % for 10 min.) and control treatments. The experiment was done in the laboratory of the Faculty of Desert Study (Semnan university). The results of tetrazolium test showed that Tilia begonifolia and Robiniapseudoacacia have 57.25 and 78.30 percent of viability, respectively. The highest rates of seed germination of Tilia begonifolia and Robinia pseudoacacia were observed in H2O2 (%38) and hot water (%66.69) treatments, respectively. As the seeds of Robinia pseudoacacia have higher seed germination than Tilia begonifolia despite of having hard seed coat, it can be concluded that other factors except of hard seed coat can affect seed germination of Tilia begonifolia.