زمان برگزاری سمینار ورودی های ۹۱

هفتم، هشتم، پانزدهم و شانزدهم دی ماه ۱۳۹۲ ساعت ۵/۸ تا ۱۴

Biochemical bases and molecular regulation of pigmentation in the peel of Citrus fruit

María J. Rodrigo ,Berta Alquézar,Enriqueta Alós, Joanna Lado, Lorenzo Zacarías

Abstract

External colour of Citrus fruits is one of the most important quality traits and a decisive factor for consumer acceptance. Pigmentation of fruit peel is highly diverse among the different species and cultivars of the genus Citrus, ranging from the green of limes to the yellow of lemons, orange in mandarins and sweet oranges, and pink in red grapefruits. Colouration of the peel is due to the presence of two main pigments: chlorophylls which provide green colour, and carotenoids, which are responsible for the characteristic colouration of mature fruits of most species and cultivars. Anthocyanins are a third group of pigments, providing a red to purple tint, in a specific group, blood oranges, and mainly restricted to the flesh. Chlorophylls and carotenoids are isoprenoid-derived pigments, synthesized and accumulated in plastids and, therefore, changes in these compounds during natural ripening are driven by the transformation of chloroplasts into chromoplasts. Most of the structural genes involved in chlorophylls and carotenoids metabolism have been characterized in Citrus, concluding that content and composition of these pigments are mostly genetically determined, and highly regulated at the transcriptional level. However, other mechanisms such as post-transcriptional regulation, the formation of specific suborganellar structures or stabilizing-complexes may also operate. Environmental factors, such as light and temperature, are known to play critical influence in the development of colouration and that biochemical and molecular bases of their action are being elucidated. Moreover, nutritional status (mainly nitrogen and sugars) is a key determinant of the rate and intensity of peel colouration. The consensus hypothesis establishes that peel colouration is governed by environmental and nutritional factors acting throughout the action of different hormonal signals. In this review we summarize content and composition of main pigments in the peel of fruits of relevant Citrus species and varieties. A comprehensive overview of metabolic pathways implicated in the metabolism of the main pigments, with emphasis on the key regulatory steps, gene expression and their regulation during fruit ripening and in response to environmental, nutritional and hormonal signals is critically revised and discussed.

مقاله کامل

Recent advances in understanding the anthocyanin modification steps in carnation flowers

Nobuhiro Sasaki¹, Yuki Matsuba, Yutaka Abe, Masachika Okamura, Masaki Momose, Naoyuki memoto, Masayoshi Nakayama, Yoshio Itoh, Yoshihiro Ozeki

Abstract

Carnations (Dianthus caryophyllus) are among the most commercially important ornamental flower crops in the world along with roses and chrysanthemums. The variation in carnation flower colors has been established through selective breeding and the genetics of this color variation have been studied for more than half a century. The cyanic coloration of carnation flowers is due to anthocyanins. Recent molecular biology studies have identified the genes that encode the enzymes involved in the biosynthesis of pelargonidin and cyanidin, the anthocyanin backbone (aglycones). The agylcones are converted into anthocyanins by attachment of a glucosyl group at either the 3- or 3,5-positions. A malyl group is then joined to the glucosyl group at the 3-position. Anthocyanidin 3,5-diglucoside can be modified by a malyl group linking the glucosyl groups at the 3- and 5-positions to form a macrocyclic ring in anthocyanidin 3,5-diglucoside. The modification step that attaches a glucosyl group to the 3-position relies on a UDP-glucose dependent glucosyltransferase in the cytosol; however, until recently, the mechanisms for malylation and glucosylation at the 5-position were unclear. It has now been found that novel enzymes, malyl-glucose dependent acyltransferase and acyl-glucose dependent 5-O-glucosyltransferase, are involved in these modifications at the 5-position and that these enzymes function in the vacuole and not the cytosol. Defects in malyltransferase prevent anthocyanin from diffusing in the vacuolar sap and cause formation of anthocyanic vacuolar inclusions that result in a dusky and metallic color in the flower petal. Several factors are now known to influence anthocyanin accumulation in vacuoles and, thereby, to influence the color of the flower.

مقاله کامل

Qualitative and quantitative control of carotenoid accumulation in flower petals

Akemi Ohmiya

Abstract

Carotenoids are lipophilic pigments widely distributed in nature. Among pigments produced in plants, carotenoids are unique in that they possess diverse functions depending on the organs and tissues in which they accumulate. The widely varying quantitative and qualitative composition of carotenoids among organs and tissues reflects these diverse functions. The green tissues of most plants show similar carotenoid profiles: Lutein, β-carotene, violaxanthin, neoxanthin, and zeaxanthin, essential components for photosynthesis, are invariably found. In contrast, carotenoid profiles of petals vary among plant species or cultivars and furnish distinct colors ranging from yellow and orange to red that attract pollinators. There is increasing evidence that the carotenoid content of petals is regulated not only by flux through the carotenoid biosynthesis pathway but also by degradation and by sequestration into chromoplasts, which function as sink organelles. These processes are mostly controlled at the transcriptional levels of relevant genes. In this review, the mechanisms that underlie the diverse carotenoid profiles of flowers are summarized with a major focus on molecular events that occur during carotenogenesis in petals.

مقاله کامل

Genotypic and environmental effects on flavor attributes of ‘Albion’ and ‘Juliette’ strawberry fruits

Kavitha Samykanno, Edwin Pang, Philip J. Marriott

Abstract

This work is aimed at investigating the genotypic and environmental effects on flavor attributes of two strawberry varieties, in particular, the Australian variety Juliette and the Californian variety Albion, when cultivated in the open field. Flavor quality parameters (i.e. pH, titratable acidity, total soluble solids content and sugar/acid ratio) and volatile compositions of these two genotypes were evaluated over ten harvest dates in one growing season. Correlations have been established between these flavor attributes with variations in air and soil temperatures, photosynthetically active radiation, relative humidity, soil moisture, and rainfall, during the growing season. While genotype was the major source of phenotypic variation for pH, titratable acidity and sugar/acid ratio, the total soluble solids content was more dependent on environmental conditions during production than on genotype. Fluctuations in soil and air temperatures, in particular, were found to significantly influence the total soluble solids content of strawberries. Furthermore, the effect of genotype was, for many volatile compounds, stronger than that of the environment. The genotype-by-environment interactions were highly significant for the four quality parameters, as well as for a majority of the volatile compounds. A set of environmental conditions have also been identified, which may be conducive for the production of highly flavorsome strawberries.

Selenium protects olive (Olea europaea L.) from drought stress

Primo Proietti, Luigi Nasini , Daniele Del Buonoimg , Roberto D’Amato, Emma Tedeschini, Daniela Businelli

Abstract

The aim of this study was to evaluate if Se could be effective in reducing the stress caused by drought on olive (Olea europaea L.). Young water-stressed trees (cv. Maurino) were treated with sodium selenate solutions (50 and 150 mg Se L⁻¹) by foliar spray. Gas exchange, relative water content (RWC) and fruit yield were compared with well irrigated trees and stressed untreated trees. Furthermore, the activity of antioxidant enzymes ascorbate peroxidase (APX; EC 1.11.1.11), catalase (CAT; EC 1.11.1.6) and glutathione peroxidase (GPOX; EC 1.11.1.9) and the variations in the content of malondialdehyde (MDA) were investigated. The results indicated that under water stress, foliar application of Se could increase photosynthesis (P_N) and fruit yield, regulate the water status of trees and maintain a sufficiently high level of leaf water content that was not achieved by the inhibition of transpiration rate (E), which instead was higher than that in water-stressed untreated trees. Se increased the activities of APX, CAT and GPOX, and reduced the content of MDA, which otherwise accumulated during oxidative perturbations. This research is the first that shows that Se application can improve olive resistance to drought, and more in general in a tree species, by protecting the cells from oxidative injuries and regulating water status.

زندگی راز بزرگی است که در ما جاریست

 
زندگی فاصله آمدن و رفتن ماست

سهراب سپهری

اولین همایش ملی برنامه ریزی،حفاظت،حمایت از محیط زیست وتوسعه پایدار

1اسفند ماه 1392

برگزارکنندگان وحامیان :

ارزیابان محیط زیست هگمتانه باهمکاری ،سازمان جهادکشاورزی استان همدان،اداره کل حفاظت محیط زیست استان همدان،اداره کل منابع طبیعی همدان،مدیریت جهادکشاورزی شهرستان نهاوند،مدیریت جهاد کشاورزی شهرستان رزن،اداره منابع طبیعی شهرستان بهار،پژوهشگاه علوم وفناوری اطلاعات ایران،سیویلیکا،کنسرسیوم محتوی ملی

محل برگزاری:همدان - دانشکده شهید مفتح

مهلت ارسال چکیده به همراه متن کامل مقالات:10بهمن1392

اعلام نتایج داوری:15بهمن ماه 1392

آخرین مهلت ثبت نام در همایش :20بهمن ماه 1392

زمان برگزاری: 1اسفندماه 1392

ثبت نام به دوصورت حضوری وغیرحضوری

وب سایت: http://bonyadhamayesh.ir/fa/

محورهای همایش :

-برنامه ریزی ومحیط زیست

-حفاظت ومحیط زیست

-مدیریت ومحیط زیست

-حمایت ومحیط زیست

-ارزیابی ومحیط زیست

-انرژی ومحیط زیست

-کشاورزی ومحیط زیست

-آلودگی ها ومحیط زیست

-نانو ومحیط زیست

-پساب ومحیط زیست

-پسماند ومحیط زیست

-تنوع زیستی ومحیط زیست

-دریاها ومحیط زیست

-تالاب ها ومحیط زیست

-حقوق ومحیط زیست

-مدیریت محیط زیست

-اسلام ومحیط زیست

-فرهنگ ومحیط زیست

-آموزش ومحیط زیست

-فناوری های نوین ومحیط زیست

-سایر ایده های نوین در جنبه حمایت، حفاظت ومدیریت محیط زیست