اثر طیف‌های مختلف نور بر کارایی فتوسنتز گیاه گل سنگ (Hypoestes phyllostachya)

نوع مقاله : مقالات پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد گروه علوم باغبانی، دانشکده کشاورزی و منابع طبیعی دانشگاه اردکان

2 اردکان

10.22067/jhs.2021.70123.1046

چکیده

کیفیت نور دریافتی توسط برگ‌ها بر فتوسنتز گیاه تاثیر می‌گذارد. در پژوهش حاضر اثر طیف‌های مختلف نور بر کارایی فتوسنتز گیاه گل سنگ (Hypoestes phyllostachya) بررسی شد. در این تحقیق با استفاده از آزمون OJIP که از روش‌های دقیق محاسبه کارایی فتوسنتز در گیاه می‌باشد، اثرات طیف نور بر فتوسنتز تجزیه و تحلیل شد. آزمایش در بهار سال 99 در گلخانه تحقیقاتی دانشگاه اردکان با شش اتاقک رشد مجهز به نور معمولی گلخانه (شاهد)، 100% نور آبی، 15% نور آبی + 85% نور قرمز، 30% نور آبی + 70% نور قرمز، 15% نور آبی + 65% نور قرمز + 25% نور سفید و 30% نور آبی + 50% نور قرمز + 20% نور سفید، روی دانهال‌های چهار برگی گیاه آپارتمانی گل سنگ در قالب طرح کاملاً تصادفی انجام شد. پس از دو ماه قرارگیری گیاهان در زیر نورهای مختلف با دوره نوری 12 ساعت روشنایی و تاریکی با شدت نوری 250 میکرومول بر مترمربع بر ثانیه، پارامترهای بیوفیزیک فتوسنتزی بررسی شد. بیشترین میزان شاخص حداکثر کارایی کوانتومی فتوسیستم II و حداکثر فلورسانس متغیر نسبی (FM/F0) در تیمارهای نوری 15% نور آبی + 85% نور قرمز، 30% نور آبی + 70% نور قرمز و 15% نور آبی + 65% نور قرمز + 25% نور سفید حاصل شد. میزان جذب نور به ازای هر مرکز واکنش (ABS/RC) در گیاهان تحت تیمار نوری 30% نور آبی + 50% نور قرمز + 20% نور سفید و نیز شاهد بیشتر از سایر تیمارها بود. میزان گرفتن الکترون به ازای هر مرکز واکنش (TR0/RC) و انرژی اتلاف شده به ازای هر مرکز واکنش (DI0/RC) در گیاهان تحت تیمار نوری 30% نور آبی + 50% نور قرمز + 20% نور سفید و نیز شاهد افزایش یافت. شاخص عملکرد بر پایه جذب انرژی نورانی در تیمار 30% نور آبی + 70% نور قرمز بالاتر بود به‌طوری‌که 25/74 درصد بیشتر از شاهد بود. نتایج پژوهش حاضر نشان داد که تیمارهای نوری ترکیبی مخصوصا 30% نور آبی + 70% نور قرمز بیشترین تاثیر را در افزایش کارایی فتوسنتز و نور آبی و شاهد کمترین تاثیر را داشتند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of Different Light Spectra on Photosynthesis Yield of Hypoestes phyllostachya

نویسندگان [English]

  • Davood Kazemi 1
  • Maryam Dehestani Ardakani 2
1 MSc student, Department of Horticultural Science, Faculty of Agriculture & Natural Resources, Ardakan University, P.O. Box 184, Ardakan, Iran.
2 Ardakan University
چکیده [English]

Introduction: Different aspects of light including intensity, quality (spectra), and duration (photoperiod) can influence plant growth and development. The growth and development of ornamental plants are also influenced by light intensity and quality. Energy saving in greenhouse production has received much attention lately. One reason for the interest in utilizing light quality to modulate plant growth and morphology is the recent development of light-emitting diodes (LEDs) as a lighting source in greenhouse production. Such small diodes can easily be placed close to the canopy and can be used to apply a narrow-band light spectrum to the plants. Specific requirements for light spectral distribution for specific processes like morphogenesis, photosynthesis, chlorophyll and anthocyanin synthesis have been determined in different species.

The aim of the current study was to investigate the biophysical properties of chlorophyll fluorescence of Hypoestes phyllostachya plants in response to different light spectra.

Materials and Methods: Research experiments were conducted on Hypoestes phyllostachya in a completely randomized design with six treatments of different light quality and three replications. The seeds were planted in plugs and in a mixture of 70% peat moss and 30% perlite. Seedlings were grown in natural greenhouse (control) and LED (100% Blue, 15% Blue +85% Red, 30% Blue +70% Red, 15% Blue +65% Red + 20% White and 30% Blue +50% Red + 20% White). Since the main goal of the study was to compare the effect of LED light quality with sunlight in conventional greenhouse conditions. The LED treatments were applied from fourth month old seedlings until five weeks in a growth chamber with the light/dark regime of 15/9 hours, 23±5°C temperature, and 65±5% relative humidity. While, their pots in the greenhouse with 55±5 mol.m-2.d-1 DLI, 21±5°C average daily temperature and 65±5% relative humidity (Data logger 8808 temp. + RH) were regarded as the control treatment. After five weeks, the fluorescence chlorophyll was measured.

Selected leaves were dark-adapted prior to the measurements and OJIP protocol was applied using a fluorometer (FluorPen FP 100-MAX, photon system instruments, Drasov, Czech Republic). The fluorescence measurement was performed using a saturating. FluorPen software was used to extract data from the original measurement. Data extracted were used to analyze the following data according to the equations of the JIP test: fluorescence intensities at 50 μs (F 50 μs, considered as the F0), 2 ms (J-step denoted as FJ), 60 ms (I-step, FI), and maximum fluorescence intensity (FM, FP). The JIP-test was used to quantify the amount of energy that flow via the PSII. Performance index was measured on the absorption basis (PIABS, a multi-parametric expression). Probability that a trapped exaction promote an electron in electron transport chain (ETC) beyond the primary acceptor Quinone (QA−), maximum quantum efficiency of PSII (FV/FM), specific energy fluxes per reactioncenter (RC) for energy absorption (ABS/RC), trapped energy flux (TR0/RC), electron transport flux (ET0/RC) and dissipated energy flux (DI0/RC) were calculated according. Finally, the data were statistically analyzed with SAS (9.4) software package, and the means were compared by LSD test at p < 0.05 level.

Results and Discussion: Fast Chl fluorescence induction curves (OJIP) was the main parameters used for the screening of different light tratments. OJIP test is shown to be a proxy to detect PSII bioenergetics and indicates changes in the status and function of PSII reaction centers, antenna, as well as in donor and acceptor sides of PSII. The maximum quantum yield of PSII (FV/FM) and relative maximal variable fluorescence (Fm/F0), significantly increased in 15% Blue +85% Red, 30% Blue +70% Red, 15% Blue +65% Red + 20% White. PIABS, one of the OIJP test parameters that provide valuable awareness about photosynthtic performance, considerably decreased under control and 30% Blue +50% Red + 20% White treatment. Unlike PIABS, ET0/RC did not show a significant difference under different treatments. The specific energy fluxes per RC for energy absorption (ABS/RC) significantly increased under control and 30% Blue +50% Red + 20% White treatment. TR0/RC increased in plants under control and 30% Blue +50% Red + 20% White treatment. Treated plants under 15% Blue +85% Red and 30% Blue +70% Red showed the lowest in dissipated energy flux (DI0/RC). During an ideal condition without any additional stress, the total PSII pool can be completely inactivate and retrieve without a detectable photoinhibition.

Conclusion: When plants exposed to 100% Blue and 30% Blue +50% Red + 20% White treatments as well as in control plants, FM/F0, FV/FM and PIABS significnatly decreased. Also ABS/RC, TR0/RC and DI0/RC, significnatly increased.

کلیدواژه‌ها [English]

  • Photosynthesis
  • Leaf chlorophyll fluorescence
  • light quality
  • Light spectra
  • Plantlet

مقالات آماده انتشار، پذیرفته شده
انتشار آنلاین از تاریخ 23 شهریور 1400
  • تاریخ دریافت: 08 اردیبهشت 1400
  • تاریخ بازنگری: 19 شهریور 1400
  • تاریخ پذیرش: 23 شهریور 1400