نوع مقاله : مقالات پژوهشی
نویسندگان
1 گروه علوم باغبانی و مهندسی فضای سبز، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
2 1- گروه علوم باغبانی و مهندسی فضای سبز، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
چکیده
با توجه به بحران روزافزون کمآبی در مناطق خشک و نیمهخشک ایران و نیاز به کاهش مصرف آب در فضای سبز شهری، استفاده از گیاهان پوششی مقاوم به خشکی بهعنوان جایگزینی برای چمن اهمیتی ویژه یافته است. این پژوهش با هدف بررسی تحمل به تنش خشکی در سه گونه گیاهی شامل فستوکا بلند(Festuca arundinacea) ، فیلا (Phyla nodiflora) و سدوم گرزی (Sedum acre) بهصورت گلدانی و در قالب طرح کاملاً تصادفی با چهار سطح رطوبتی ۲۰، ۴۰، ۶۰ و ۸۰ درصد ظرفیت زراعی و سه تکرار انجام گرفت. پس از استقرار کامل گیاهان، دوره اعمال تنش خشکی و بررسی صفات بهمدت ۷۵ روز ادامه یافت. صفات مورفولوژیک نظیر ارتفاع اندام هوایی، طول ریشه و وزن تر و خشک اندامها، و همچنین صفات فیزیولوژیک مانند محتوای نسبی آب برگ، نشت الکترولیت، کلروفیل مورد ارزیابی قرار گرفت. نتایج نشان داد که فیلا در بیشتر صفات عملکرد بهتری نسبت به سایر گونهها داشت و مقاومت بالاتری به تنش خشکی از خود نشان داد، در حالیکه سدوم گرزی حساسترین گونه بود. بیشترین ارتفاع اندام هوایی در گیاه چمن در سطح شاهد، (80 درصد رطوبت) بود که با سطح تنش FC 60% تفاوت معنیداری نداشت اما در گیاه فیلا بیشترین ارتفاع در سطح 60 درصد رطوبت مشاهده شد. در گیاه چمن، بیشترین مقدار کلروفیل b در سطح تنش ۶۰ درصد ظرفیت زراعی مشاهده شد. گیاه فیلا بیشترین مقدار این صفت را در سطح چهارم تنش (۲۰ درصد ظرفیت زراعی) داشت و گونه سدوم گرزی نیز الگوی مشابهی با گیاه چمن نشان داد. با افزایش شدت تنش خشکی، کاهش معنیداری در شاخصهای رشد و فیزیولوژیکی مشاهده شد. یافتههای این تحقیق نشان میدهد که فیلا میتواند بهعنوان گزینهای مناسب و کممصرف در طراحی فضای سبز شهری در مناطق خشک پیشنهاد گردد. با این حال، بررسیهای بیشتر در مقیاس میدانی و بلندمدت برای تأیید کارایی این گونهها در شرایط مختلف اقلیمی و مدیریتی توصیه میشود.
کلیدواژهها
موضوعات
عنوان مقاله [English]
Assessment of Physiological and Morphological Traits in Three Ground Cover Species for Urban Green Spaces under Drought Stress
نویسندگان [English]
- Mohammad Ahmadpour, 1
- Azadeh Mousavi Bazaz 2
- Ali Tehranifar 1
1 Department of Horticultural Science and Landscape Architecture, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
2 Department of Horticulture and Landscape engineering, Faculty of Agriculture, Ferdowsi University of Mashhad
چکیده [English]
Introduction
Water scarcity, along with growing population and global warming, forms a serious worldwide problem for desert countries such as Iran. Since the rainfall every year is limited, effective use of water resources is of utmost significance. Substitution of lawns with high-water-demand requirements, by drought-resistant, native ground cover plants, is one of the key steps. lawns establish quickly, but are expensive to maintain with high watering reqirements, and hence are unsuitable for current climatic conditions. Previous studies have shown that sustainable management practices such as soil improvement, mulching, and advanced irrigation systems such as subsurface irrigation can reduce water consumption. Urban green spaces play an important role in enhancing environmental quality and public health, and drought-resistant ground covers can assist in the achievement of international green space standards. These plants improve soil health, minimize erosion, inhibit weeds, and require less upkeep than traditional lawns. The aim of this research was to examine the performance of different species of ground covers as alternatives to lawns for the purposes of improving the efficiency of water use and biodiversity in urban environments.
Materials and Methods
This August 2024 greenhouse experiment was conducted at Ferdowsi University of Mashhad (36°20′N, 59°39′) to compare responses to drought stress among selected groundcover species. Festuca arundinacea was sown at 12 g per pot, and Phyla nodiflora and Sedum acre were grown from uniform rooted cuttings. A completely randomized factorial design with four irrigation levels (20%, 40%, 60%, and 80% of field capacity) and three replications was used. Drought treatment started after full establishment for 75 days. Morphological traits (shoot height, root length, fresh and dry biomass) physiological, (relative water content, electrolyte leakage), and biochemical parameters (chlorophyll a and chlorophyll b) were measured at the end of the experiment. Relative water content (RWC) and Electrolyt leakage (EL) were measured using standard procedures, and pigment contents were measured by spectrophotometry. Daily water consumption was measured gravimetrically. Data were statistically examined using ANOVA and Duncan's multiple range test at a 5% significance level in Minitab 22, with graphs prepared in Excel.
Results and Discussion
Results indicated that drought stress had a great effect on morphological traits across all the species with Sedum acre being most sensitive, particularly in root length and biomass. Festuca arundinacea had optimal growth and biomass at 60% field capacity, signifying moderate drought tolerance. Physiological and biochemical traits, like relative water content (RWC), electrolyte leakage (EL), chlorophyll content, were all impacted by drought greatly. The greatest shoot height in Festuca was observed under the control condition (80% field capacity), which was not significantly different from the 60% field capacity treatment. However, in Phyla spp., the highest shoot height was recorded at 60% field capacity, which differed significantly from both the milder and more severe stress levels. The highest relative leaf water content (RWC) in tall fescue, goldmoss stonecrop, and phyla plants was observed at 80% field capacity (FC 80%), with no significant difference between the first (80% FC) and second (60% FC) irrigation levels. Furthermore, across all species, RWC generally decreased with increasing drought stress intensity, and the lowest values for this trait were recorded under the most severe stress level (20% FC) for all plants. In all the plant species, the highest levels of electrolyte leakage were observed under the most severe stress conditions (the fourth and third levels of drought stress). Phyla nodiflora maintained higher levels of relative water content during drought stress, demonstrating enhanced tolerance to water scarcity.The findings indicate the potential of drought-resistant groundcovers for water-saving urban landscaping.
Conclusion
The groundcover species examined in this study responded differently to drought stress. Phyla nodiflora performed better in most physiological and morphological parameters with notable tolerance to water deficit stress. On the other hand, Sedum acre was the most sensitive plant to drought. As drought severity increased, key parameters such as root length, fresh biomass, relative water content of leaves, and chlorophyll content reduced, whereas electrolyte leakage increased. These findings reinforce the importance of utilizing drought-tolerant species like Phyla nodiflora for future sustainable desert urban landscape design. Replacement of high-water-demand lawn with such robust groundcovers can help significantly in the preservation of water resources. However, more studies need to be carried out to find out the long-term adaptation and adaptability of these species under diverse weather and irrigation regimes.
کلیدواژهها [English]
- Drought Stress
- Lawn alternative
- Lawn
- Urban Green Space
- Ground Cover Plant
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