نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 گروه جنگلشناسی و اکولوژی جنگل، دانشکده علوم جنگل، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
2 گروه جنگلشناسی و اکولوژی جنگل، دانشکده علوم جنگل، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران
3 دانشآموخته دکتری علوم جنگل، اداره کل منابع طبیعی و آبخیزداری استان گلستان، گرگان، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Water restrictions are one of the most important climate factors in Iran that affect plant growth through internal stresses. Considering the significant contribution of Popolus deltoides in woody farming, knowledge about the effects of water-deficit stress, the determination of the wilt threshold, and the resistance of different clones of Popolus deltoides to different levels of water-deficit stress seems to be necessary. In this study, the effect of drought stress treatments on growth, leaf morphological, physiological, and stomatal characteristics of the Populus deltoides seedling clones were investigated.
Materials and methods: To conduct this research, In the March of 2016, 60 cuttings from four of the Populus deltoides clones (P.d 63.51, P.d 67.51, P.d 69.55, P.d 77.51) available in the forest of sixty kalate preparations And the nursery of this forest in plastic pots with forest soil, The leaves were grown in a ratio of 1:1 and cultivated for 6 months under the same conditions. Then, 7 similar 6-month-old potted seedlings were selected from the studied clones of Populus deltoides and transferred to the greenhouse, and treatments based on field capacity, Irrigation, and then every day were kept at the corresponding capacity through weighing. Analysis of traits related to enzymes (peroxidase enzyme and ascorbate peroxidase enzyme), pigments (chlorophyll a, b, total, and carotenoid), Survival, and water requirement With the help of a factorial test of two factors with seven repetitions in each level in the form of a completely random design, other traits were carried out using the analysis of variance of one factor (ANOVA) with seven repetitions in each level in the form of a completely random design. Water stress treatments were applied from September for two weeks at each stress level under greenhouse conditions at the Faculty of Natural Resources of Gorgan University of Agricultural Sciences and Natural Resources.
Results: Based on the results of vegetative character studies, water stress caused a change in stem height, leaf number, Stem fresh weight, Stem dry weight, the amount of stem water, root fresh weight, root dry weight, the amount of root water, root to stem weight ratio and leaf shape factor. Also, The stress was significantly affected by leaf morphological characteristics on leaf length, leaf width, leaf length-to-width ratio, leaf shape factor, leaf area, and leaf area index. While among the micromorphological parameters, drought stress only caused different stomatal width changes between the studied clones. The results of this part of the study showed the clones P.d 77.51 and P.d 63.51 as successful clones against water stress. According to the results of physiological experiments, with increasing water-deficit stress, chlorophyll a, b, total and carcinoid decreased, but the levels of peroxidase and ascorbate peroxidase increased. Seedlings were affected by water deficit stress under 75% of the field capacity and increasing physiological reactions such as increasing the amount of peroxidase and ascorbate peroxidase, which moderates the tension the plant has coped well with 75% and 50% surface tension. In this section, P.d 77.51 and P.d 63/51 clones were more successful than others.
Conclusion: The results of this research showed that the beginning of the processes of response to water shortage stress was at the level of 75% of the field capacity so if it reaches below 50% of the field capacity, it is fatal. Therefore, watering seedlings for wood cultivation or producing seedlings in the nursery with the studied clones of Populus deltoides should be in such a way that the field capacity of the soil does not decrease from 50% In the comparison between the studied clones, P.d 77.51 and P.d 63.51 were introduced as more resistant to water stress.
کلیدواژهها [English]