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2. Growth and some photosynthetic characteristics of field grown Avena sativa under copper and lead stress
- Creator:
- Moustakas, M., Lanaras, T., Symeonidis, L., and Karataglis, S.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- A fíeld experiment was conducted to evaluate the effects of Cu and Pb on photosynthesis and growth characteristics of oats. The plants grown on the site with elevated levels of Cu-Pb were reduced in height and biomass, compared to control plants, and appeared chlorotic while the accumulations of both Cu and Pb in the above-ground parts were in the range considered to be phytotoxic. Cu and Pb led to a pronounced reduction (47 %) of chlorophyll (Chl) (a + b) content, accompanied by proportional changes in ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activity. Hence Cu and Pb effects did not result in the destruction of the photosynthetic apparatus but in its coordinated reduction. Growth at the heavy metal contaminated site resulted in a decreased (7 %) quantum yield of photochemistry in photosystem 2 (PS2), as given by the ratio Fy/Fn, measured in dark adapted leaves in the field. The half-rise time (ti/2) from the initial (Fq) to maximal (F^) Chl fluorescence was increased, suggesting that the amount of active pigments associated with the photochemical apparatus decreased and that the functional Chl antennae size of the photosynthetic apparatus was smaller compared to the control plants. Although Cu and Pb affected the photosynthetic apparatus in multiple ways, the prevailing effect was that on RuBPCO activity, which in tum must háve limited the overall photosynthetic activity.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Impact of simulated acidic rain on growth, photosynthetic pigments, cell metabolites, and leaf characteristics of green gram
- Creator:
- Kumaravelu, G. and Ramanujam, M. P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll, leaf wettability, mesophyll volume, plant height, starch, stomatal index, sugars, and Vigna radiata
- Language:
- Multiple languages
- Description:
- Seedlings of green gram (Vigna radiata cv. ADT-1 and CO-5) were exposed to daily showers of simulated acidic rain (H2SO4 : HNO3 : HCl, 4 : 2 : 1, v/v) for 10 d. The effects were analysed after 5 and 10 showers, respectively. Rain of pH 2.5 inhibited seedling growth and biomass accumulation, though in other acidic levels the effects were mostly inconsistent. Both cultivars had high degree of surface wettability indicated by high leaf surface contact angles and water-holding capacity. Treated leaves were thinner with smaller mesophyll cells. Stomatal index and trichome density were lower in contrast to epidermal cell density and stomatal frequency which increased with increasing acidity. Decreases in chlorophyll (Chl), carotenoid (Car), and starch contents in cv. ADT-1 at pH 2.5 were observed after 5 showers, while in cv. CO-5 decreases were noted only after 10 showers. In contrast to total sugar levels, the protein content of cv. CO-5 was augmented significantly after simulated acidic rain (SAR) treatment. and G. Kumaravelu, M. P. Ramanujam.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Two species of philometrid nematodes (Philometridae) from marine fishes off Japan, including Philometroides branchiostegi sp. n. from Branchiostegus japonicus (Malacanthidae)
- Creator:
- Moravec, František, Nagasawa, Kazuya, and Nohara, Kenji
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- parasitic nematode, Philometra, Philometroides, marine fish, Branchiostegus, Acanthogobius, Pterogobius, Sea of Japan, and Japan
- Language:
- English
- Description:
- Gravid females of two species of philometrid nematodes (Philometridae) were collected from marine perciform fishes in Japanese waters, mainly from the southern Sea of Japan. Based on light microscopy and scanning electron microscopy examinations, the previously described but poorly known species Philometra cryptocentri Yamaguti, 1961 is redescribed from specimens recovered from the abdominal cavity of Acanthogobius flavimanus (Temminck et Schlegel), Pterogobius elapoides (Günther) and P. zonoleucus Jordan et Snyder (all Gobiidae) (all new host records); the number (14) and arrangement of cephalic papillae in this species are described for the first time. The new species, Philometroides branchiostegi sp. n. from head tissues of Branchiostegus japonicus (Houttuyn) (Malacanthidae), based on a single specimen, is mainly characterized by the embossment of the entire body except for the cephalic end, presence of four submedian pairs of large cephalic papillae of external circle and two small lateral single papillae of internal circle, pair of large papilla-like caudal projections, the oesophagus with a distinct anterior inflation, by a markedly small body (length about 18 mm) and the larvae 306-465 µm long.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public