Are there any effects of enhanced UV - B radiation on Chara polyacantha and Nitella hyalina under laboratory conditions ?

نویسنده

  • María A. RODRIGO
چکیده

Attenuation of UV-B radiation in the water column occurs due to absorption and scatter but in shallow clear freshwater systems enhanced UV-B radiation might be of importance in affecting aquatic organisms. Two laboratory experiments were performed to determine whether two species of charophytes typical for shallow waterbodies, such as Chara polyacantha and Nitella hyalina, are negatively affected by UV-B radiation. Each experiment had two treatments: (i) the photosynthetic active radiation (PAR) treatment and (ii) the enhanced UV-B+PAR treatment. We focussed on the influence on growth rate, photosynthetic pigment concentration and the amount of methanol soluble UV absorbing compounds which can act as a screen preventing radiation damage. UV-B radiation increase in the Extremely Enhanced UV-B Radiation Experiment (> 15 kJ·m·day UV-B dose) reduced average charophyte length in both species after three weeks of incubation and caused depigmentation and cracking of the charophytes. However, in the Enhanced UV-B Radiation Experiment (3.6 kJ·m·day UV-B dose) we found a large variability in the length of charophyte individuals in both treatments after 22 and 49 days what caused that there were not statistically significant differences in the growth rates of both charophyte species. However, significant differences in C. polyacantha growth rate were found after four months of exposure. There were not either significant differences in chlorophyll a concentration in C. polyacantha charophyte tissues among the treatments. On the other hand, N. hyalina increased its chlorophyll concentration in the PAR+UV-B treatment. In both experiments, we did not find statistically significant increased levels of methanol soluble UV absorbing compounds under enhanced UV-B conditions. The lack of induction of this kind of compounds in C. polyacantha and N. hyalina under augmented UV-B doses during our experiments is in agreement with other Authors results for Chara aspera, and make us to consider charophytes as potentially sensitive organisms to UV-B radiation.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Changes in Physiological and Biochemical Parameters of Gourd (Cucurbita pepo L.) Two Varieties under Drought and UV-B Radiation. Nobar Hajihosseinlo*, Siavash Hosseini Sarghein and Rashid Jamei

It emerged recently that there is an inter-relationship between drought and Ultraviolet-B (UV-B) radiation in plant responses, in that both stresses provoke an oxidative burst. The objective of the present investigation was to study the effect of drought stress, UV-B radiation and the combined effects of UV-B and drought stresses on two cultivars of gourd seedling. The gourd plants were grown w...

متن کامل

Study of phytohormones effects on UV-B stress seeds of thyme species

Background & Aim: Thymus vulgaris L. and Thymus daenensis Celak (Thyme), members of the family Lamiaceae, are widely used in Iranian folk medicine. The aim of this research was to study how salicylic acid (SA), gibberellin (GA), and indole acetic acid (IAA)-seed priming affect UV-B radiation in seeds of Thyme (T. vulgaris, T. daenensis </...

متن کامل

Study of phytohormones effects on UV-B stress seeds of thyme species

Background & Aim: Thymus vulgaris L. and Thymus daenensis Celak (Thyme), members of the family Lamiaceae, are widely used in Iranian folk medicine. The aim of this research was to study how salicylic acid (SA), gibberellin (GA), and indole acetic acid (IAA)-seed priming affect UV-B radiation in seeds of Thyme (T. vulgaris, T. daenensis </...

متن کامل

Morphological and Biochemical Responses of Basil Plant Under Ultraviolet Radiation-B and Deficit Irrigation Under Greenhouse Conditions

Environmental stresses such as deficit irrigation and ultraviolet radiation can influence plant growth and development. Among the environmental variables, ultraviolet radiation is an important factor in plant response to other stresses, such as deficit irrigation. The purpose of this study was to investigate the effects of ultraviolet B radiation (UV-B), irrigation stress and combined effects o...

متن کامل

The Impact of UV-B Radiation on Some Metabolites and Pigments of Carum Copticum Under In vitro Culture

Carum copticum L. is a medicinal plant of the Apiaceae family with medicinal properties. In this study, the effects of UV-B radiation on the photosynthetic pigments and essential oils as well as phenols and anthocyanin of the seedling and callus of C. copticum were investigated under in vitro conditions. For this purpose, the experiment was set up in a completely randomized design, with three r...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2011