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Register a new userUsing of Photosynthetic electron transport as an indicator of photosynthesis efficiency
استخدام النقل الالكتروني الضوئي كمؤشر على فعالية التركيب الضوئي
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تمت دراسة النقل الالكتروني الضوئي كمؤشر للتعبير عن فعالية التركيب الضوئي عند صنفين من القمح الطري ACSAD 899 ، ACSAD 1059 تحت تأثير أحد الاجهاد الملحي. تم إجراء التجربة في مزارع رملية نقية بإضافة محلول مغذي ضمن غرفة نمو، و تم تعريض النباتات بعمر 14 يوم لتركيز 100 ميلي مول من كلوريد الصوديوم (NaCl)، ثم قيست معدلات النقل الالكتروني الضوئي في الأغشية الثايلاكويدية لتلك النباتات بعمر 21، 28، 35 يوم. لُحظ انخفاض معدل النقل الالكتروني الضوئي عند الصنف ACSAD 899 بنسبة وصلت لـ 57% في اليوم الأخير من التجربة، بينما بلغت هذه النسبة حوالي 24.6% عند الصنف ACSAD 1059. يؤدي تناقص معدل النقل الالكتروني الضوئي إلى تناقص في معدلات إرجاع غاز CO2 وبالتالي انخفاض في انتاجية النبات، و هو ما يمكن اعتماده كمعيار للتعبير عن فعالية التركيب الضوئي.
Photosynthetic transport was studied as an indicator of photosynthesis efficiency in two bread wheat cultivars (ACSAD 899, ACSAD 1059) under the influence of one of the salt stress. This study was carried out in sand cultures irrigated with nutrient solution in a growth chamber, and 14 days seedlings were treated with 100 mM of sodium chloride. Later the electron transport rates in those plants thylakoids were measured in 21, 28, 35 days of the experiment. Electron transport rates decreased in ACSAD 899 and reached 57% in the last day of the experiment, while it was 24.6% in ACSAD 1059. The decrease in photosynthetic electron transport rate leads to a decrease in the reduction rate of CO2 and the plant productivity as a consequence. Therefore, it could be used as criterion to express photosynthesis.
References used
ABDESHAHIAN, M.; NABIPOUR, M. and MESKARBASHEE, M. (2010): Chlorophyll fluorescence as criterion for the diagnosis salt stress in wheat (Triticum aestivum) plants. World Academy of Science, Engineering and Technology 71, 569 – 571
AYERS, A. D.; BROWN, J. W. and WADLEIGH, L. (1952): Salt tolerance on barley and wheat in soil plots receiving several salinization regimes. Agron. J., 44, 307- 310
AZIZOV, I. V.; KHANISHEVA, M. A. (2010): Pigment content and activity of chloroplasts of wheat genotypes grown under saline environment. Proceedings of ANAS (Biological Sciences) 65 (5-6), 96 – 98
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Young sun flower plants were exposed to ultraviolet radiation of the type UV-B (295
nm) for 3 days (2 hours per day) with or without excluding the UV-radiations using
polyethylene layers (blue and transparent) (0.5 mm thick). The amount of photosyn
thesis
pigments was measured whereby a variation in the chlorophyll contents. Chlorophyll a
(chl.a) was noticed at these rates (without covering 19.59%, transparent polyethylene
3.40%, blue polyethylene 1.66%), chlorophyll b (chl.b) at rates (7.81, 25.13, 22.79%) and
the total chlorophyll content (2.88, 21.76, 20.53%), while the amount of carotenoid
pigments has increased in the studied samples (24.45, 19.23, 17.32%). A decrease in the
rate of photosynthetic electron transport has also been noticed (88.04, 78.71, 58.81%) in
the plant samples exposed to ultraviolet radiation (on the third day) without UV excluding
and with transparent and blue polyethylene successively. All results were compared to the
sample which was not exposed to radiation.
All results indicate the negative effect of ultraviolet radiation on the chlorophyll
content and the rate of photosynthetic electron transport, therefore, on photosynthesis and
the productivity of sun flower plants. They also point out the importance of carotenoid
pigments in protecting chlorophyll pigments from the negative effects of this radiation.
Results showed the clear positive effect of polyethylene layers, specifically the blue one, in
protecting plants against this radiation.
The study was conducted during 2017 in the laboratories of the department of Botany
at Tishreen University, Lattakia, Syria. The effect of ultraviolet radiation (UV-C and UVB)
for different periods (0.5, 1, 3, 5, 15, 15, 30, 45, 60 minutes) on the
photosynthetic
pigments of Euglena gracilis (with three stages of measurements) was studied. The results
showed that chlorophyll pigments were more sensitive to UV-C compared to UV-B. These
reductions were correlated with the increase in the exposure time, reaching the lowest
value after 60 minutes exposure (97.83, 98.73, 99.18% for chlorophyll a, chlorophyll b and
carotenoids when measured after 24 hours respectively).
The polyethylene films protect the chlorophyll pigments against UV radiation.
The protection rate was more evident against UV-C reaching .7.7% after 24 hours in the
algae exposed for 30 minutes according to the experimental conditions.
To clarify the possibility of using bacterial flora as a pollution indicator,
water samples from river were collected and analyzed from July ١٩٩٩ to
February ٢٠٠١ for dissolved oxygen (DO), NO٣-N, NO٢-N, NH٤-N, PO٤-P,
suspended solids (SS), biolog
ical oxygen demand (BOD) Heterotrophic Bacteria
were identified to genus level, and another part of it was identified to
Enterobacteriaceae.
Recent studies have proposed different methods to improve multilingual word representations in contextualized settings including techniques that align between source and target embedding spaces. For contextualized embeddings, alignment becomes more c
omplex as we additionally take context into consideration. In this work, we propose using Optimal Transport (OT) as an alignment objective during fine-tuning to further improve multilingual contextualized representations for downstream cross-lingual transfer. This approach does not require word-alignment pairs prior to fine-tuning that may lead to sub-optimal matching and instead learns the word alignments within context in an unsupervised manner. It also allows different types of mappings due to soft matching between source and target sentences. We benchmark our proposed method on two tasks (XNLI and XQuAD) and achieve improvements over baselines as well as competitive results compared to similar recent works.
The personality constitutes a set of traits and characteristics that distinguish each individual from others. The human personality is distinct and different from one person to another, and each personality has a set of traits that determine its characteristics, weaknesses, strengths, flexibility and ability to conform.
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