تاثیر سطوح آبیاری و پیوند بر رشد و شاخص‌های فتوسنتزی گوجه‌فرنگی گلخانه‌ای رقم دافنیس

در این پژوهش امکان پرورش گوجه‌فرنگی گلخانه‌ای رقم دافنیس با صرفه‌جویی در مصرف آب از طریق پیوند بر روی پایه‌های مختلف و با بررسی فرایند فتوسنتز و رشد مورد بررسی قرار گرفت. آزمایش به‌صورت کرت‌های خردشده در قالب طرح پایه کاملاً تصادفی اجرا شد که کرت اصلی سطوح آبیاری (دور آبیاری 3، 6 و 9 روز) و کرت فرعی شامل 9 ترکیب مختلف پیوندی بود. گیاهان گوجه‌فرنگی پس از پیوند و استقرار در گلخانه به‌مدت 4 ماه تحت تاثیر سطوح آبیاری قرار گرفتند و در هر نوبت تا حد گنجایش مزرعه‌ای آبیاری شدند. نتایج آزمایش نشان داد که شدت فتوسنتز در تمام ترکیبات پیوندی 36 روز پس از آغاز سطوح آبیاری یکسان بود و با شاهد غیرپیوندی تفاوتی نداشت اما پس از گذشت 72 روز، شدت فتوسنتز در پایه امپرادور بیش از شاهد بود. شاخص‌های فلورسانس کلروفیل در این آزمایش حساسیت لازم برای نشان دادن آثار تنش خشکی و نقش پایه‌ها بر آن را نداشتند. پایه گوجه‌فرنگی گیلاسی علاوه بر دارا بودن سیستم ریشه‌ای گسترده‌تر نسبت به سایر پایه‌ها، موجب رشد بیش‌تر شاخساره در تمام سطوح آبیاری شد اگرچه کم‌ترین کاهش وزن ریشه در پایه بادمجان محلی یزد مشاهده شد. در کل می‌توان چنین نتیجه‌گیری کرد که فرایند فتوسنتز در این آزمایش بیش‌تر تحت تاثیر برهم‌کنش عوامل محیطی و پیوندک قرار گرفت و پایه‌های مورد استفاده نقش چندانی در این رابطه نداشتند همچنین میزان رشد سیستم ریشه‌ای و شاخساره گیاه پیوندی بیش‌تر تحت تاثیر قدرت ژنتیکی پایه قرار دارد و فعالیت‌های فتوسنتزی گیاه سهم کم‌تری را به‌خود اختصاص می‌دهند. 

effect of irrigation levels and grafting on growth and photosynthetic activities of greenhouse dafnis tomato

abstractin this study, the possibility of growing greenhouse tomato cv. dafnis with saving water consumption through grafting on different rootstocks was investigated by studying photosynthesis and plant growth. the experiment was carried out in the form of split plots based on completely randomized design in which the main-plot was irrigation levels (irrigation intervals of 3, 6 and 9 days) and the sub-plot consisted of 9 different grafting combinations. after grafting and establishment of tomato plants in greenhouse, the plants were exposed to the irrigation levels for 4 months and all were irrigated up to field capacity. photosynthesis parameters were measured in four stages and shoot and root dry weights were determined at the end of the experiment. based on the results, photosynthetic parameters were reduced by the intensity and duration of drought stress. the experimental results showed that the rate of photosynthesis was the same in all grafting combinations 36 days after the start of irrigation levels. however, after 72 days, the rate of photosynthesis in the “emperador” rootstock was higher than in the control. the chlorophyll fluorescence indices were not sensitive to show the effects of drought stress and the role of rootstocks. cherry tomato rootstock, in addition to having an extensive root system than the other rootstocks, resulted in more shoot growth at all levels of irrigation, although the least reduction in root weight was observed in the local eggplant rootstock of yazd. in general, it can be concluded that the photosynthesis in this experiment was more affected by the interaction of environmental factors and grafting and the rootstocks used did not play a significant role in this regard. furthermore, root and shoot growth traits were more affected by genetic potential of rootstock, and photosynthetic activities of the plant had a minor influence on them.background and objective: the cultivation of tomato is often threatened by drought stress periods as this crop is largely dependent on sufficient water supply (1). the magnitude and intensity of drought are predicted to increase under climate change scenarios, particularly in semi-arid regions, where water is already a scarce resource. hence, it is imperative to devise strategies for mitigating the adverse effects of drought on tomato through improvement in the plant’s efficiency of root water uptake. since the root is the entry point for water, its intrinsic structure and functions play a crucial role in maintaining the soil–water–plant continuum during moisture deficit at the rhizosphere. grafting offers a great opportunity to replace the root system of the cultivated tomato plants with that of wild species and hence provide a rapid solution to modulate root system architecture in contrast to the time-consuming conventional breeding approach (2). in this study, the possibility of growing greenhouse tomato of dafnis cultivar by saving water consumption through grafting on different rootstocks and from the point of photosynthesis and growth view was investigated.materials and methods: the experiment was carried out in the form of split plots based on completely randomized design in which the main-plot was irrigation levels (irrigation intervals of 3, 6 and 9 days) and the sub-plot consisted of 9 different grafting combinations. after grafting and establishment in the greenhouse, tomato plants were exposed to the irrigation levels for 4 months and all were irrigated up to field capacity. photosynthesis and chlorophyll fluorescence parameters were measured in 4 stages and shoot and root dry weights were determined at the end of the experiment.results: based on the results, photosynthetic parameters were reduced by the intensity and duration of drought stress. the intensity of photosynthesis was the same in all grafting combinations 36 days after the start of irrigation levels and was not different from the non-grafted control plants. however, after 72 days, the rate of photosynthesis in the “emperador” rootstock was higher than in the control. in this experiment, chlorophyll fluorescence indices were not sensitive to show the effects of drought stress and the role of rootstocks. cherry tomato rootstock had, an extensive root system than the other rootstocks, resulted in more shoot growth at all levels of irrigation, although the least reduction in root weight was observed in the local eggplant rootstock of yazd.conclusions: in general, it can be concluded that the process of photosynthesis was more affected by the interaction of environmental factors and grafting, and the rootstocks used did not play a significant role in this regard. furthermore, root and shoot growth traits were more affected by genetic potential of rootstock, and photosynthetic activities of the plant had a minor influence on them. grafting as a healthy technique may increase the resistance of tomato plants against drought stress depending on the genotype of the rootstock.references:1. jiang, l., wang, y., zhang, s., he, r., li, w., han, j., cheng, x., 2017. tomato sldreb1 gene conferred the transcriptional activation of drought-induced gene and an enhanced tolerance of the transgenic arabidopsis to drought stress. plant growth regulation 81: 131–145.2. rouphael, y., kyriacou, m.c., colla, g., 2018. vegetable grafting: a toolbox for securing yield stability under multiple stress conditions. frontiers in plant science 8: 2255.