نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری، گروه زراعت و اصلاح نباتات، پردیس کشاورزی و منابع طبیعی دانشگاه تهران
2 استادیار، پژوهشکدۀ بیوتکنولوژی کشاورزی ایران
3 دانشیار، گروه زراعت و اصلاح نباتات، پردیس کشاورزی و منابع طبیعی دانشگاه تهران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
To study the effect of soil moisture variation on growth and steviol glycosides contents in Stevia (Stevia rebaudiana B), a potexperiment based on a randomized complete design with four treatments and three replications were conducted in a greenhouse of Agricultural Biotechnology Research Institute of Iran (central region, Isfahan), in 2012. Experimental treatments applied as a combination of visual symptom appearance in plant (normal to severe wilting) and soil moisture. So, treatments irrigated in 19.1, 15.1, 11.9 and 9.1% of soil moisture content (w/w) that are created in greenhouse situation with irrigation of 3, 6, 9 and 12 days interval, respectively. Results showed that soil moisture reduction up to 9 days irrigation interval had no effect on plant height and leaf dry weight, but plant growth significantly reduced in 12 days irrigation period. Maximum of harvest index obtained in 6 days irrigation period (51.36%). Soil moisture reduction caused significant increment in stevioside and dulcoside A, but not affected the rebaudioside types (A, F and C). Total steviol glycosides increased with the soil moisture reduction and plant grown with 3 days irrigation interval had minimum steviol glycosides. Stevioside was highest in steviol glycosides in all treatments. Plants grown under 6 days irrigation interval had the maximum of steviol sugar yield. Totally, the results of this experiment showed that leaf dry weight decreased with decline of soil moisture content (below 11.9 w/w), but steviol glycosides content had significant increment. The highest of harvest index and steviol sugar yield were obtained in the 6 days irrigation interval. Although, steviol glycosides content increased with the soil moisture reduction, it means that intensify of drought stress more than 6 days irrigation interval (reduction of soil moisture content below the 15.1 w/w) caused downfall of Stevia yield due to significant reduction of leaf yield and steviol sugar yield in severity of drought stress.
کلیدواژه‌ها [English]
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