نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 گروه باغبانی، دانشکده تولید گیاهی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان
2 گروه علوم باغبانی و فضای سبز،دانشکده تولید گیاهی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
3 علوم باغبانی، دانشکده تولید گیاهی، دانشگاه علوم کشاورزی گرگان
4 موسسه مشکلات پایه بیولوژیک روسیه
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Purpose: Improvement of plant tolerance to adverse environmental conditions has been proven by phytohormones in various plants species. However, the crosstalks between salicylic acid and jasmonic acid hormones under drought stress conditions have not been studied. Therefore, in this study, changes in the growth rate of aerial and underground organs as well as the proline content of aerial parts and roots of R. damacena to jasmonic acid and salicylic acid during the cource of drought stress conditions at three different times point were investigated.
Materials and Methods: Clonally propagated plants sown into plastic pots were exposed to constant water shortage at 25, 50 and 100% of field capacity for 11 days. Plants under different drought stress treatment foliar spraied with jasmonic acid (50 μM) and a combination of jasmonic (50 μM) and salicylic acid (1.5 μM). The first foliar application was performed a few days before the first day of the experiment and twice after the start of the water stress at intervals of seven days. Sampling was performed on days 1, 4 and 11 and morphophysiological responses (stem height, root fresh weight, root dry weight, Ionic leakage) and biochemical (leaf proline and root proline) were measured. The experiment was performed in factorial format and in a completely randomized block.
Results: Regardless of hormonal treatment, the measured traits such as stem height, root fresh weight, root dry weight decreased compared to the control and other traits such as leaf and root proline, ion leakage increased compared to the control in drought stressed plants. Plants grown under 25% of FC showed a 4 fold increase in proline content when exposed to JA in contrast to that of control sprayed with distilled water after 4 days. This increase in proline content in shoots and roots was similar. However, non-drought stressed plants which were exposed to JA, did not show such changes. The results show that the combination of SA and JA reduces the amount of ion leakage of leaves and the proline content of roots and shoots by half to the amount produced in plants sprayed with distilled water at 25% of FC and this amount of proline is very close to non-drought stressed plants. The results showed that the loss of fresh and dry weight of roots, which was evident in JA–received plant under 25% of FC can potentially be reversed by combination of SA and JA. This was also truth for stem height.
Conclusion: The drought stress mitigation of SA by reversing JA effects manifested in mitigating cell ion leakage, and increase in root fresh and dry weight. Reducing the root and shoot proline content and leaf ion leakage in plant exposed to combination of JA and SA compared to JA alone indicated a negative regulatory effect of SA on JA on modulating leaf and shoot proline content as a physiological indicator of drought tolerance.
کلیدواژه‌ها [English]
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