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41.
Hideaki Yamada Kenta Nakamoto Jun Hayakawa Tomohiko Kawamura Koetsu Kon Hiromori Shimabukuro Kouki Fukuoka 《Fisheries Science》2018,84(3):461-468
We estimated the leaf growth of the tropical–subtropical seagrass species Cymodocea serrulata using the conventional leaf-marking method in a subtropical seagrass bed on Ishigaki Island, southern Japan, which is near the northern distributional limit of this species. This survey was conducted over an annual cycle at two sites. The deep site was located in a dense meadow in the subtidal zone. The shallow site was located around the lowest part of the intertidal zone, forming a tide pool during ebb tides of the spring tide, which was considered to approximate the upper depth limit of C. serrulata. The relationships between temperature and shoot weight, and the number of leaves per shoot were significantly influenced by site, resulting in a lower biomass in the shallow site. Leaf growth and shoot length increased with temperature without any spatial variation. Leaf growth and the number of leaves per shoot particularly declined during periods of low temperature in both sites. These results suggest that leaf growth and phenology of C. serrulata in this subtropical area are largely regulated by temperature. 相似文献
42.
Understanding seasonal changes in photosynthetic characteristics of canopy leaves is indispensable for modeling the carbon balance in forests. We studied seasonal changes in gas exchange characteristics that are related to the temperature dependence of photosynthesis in canopy leaves of Quercus crispula Blume, one of the most abundant species in cool-temperate forests in Japan. Photosynthetic rate and ribulose-1,5-bisphosphate (RuBP) carboxylation capacity (V(cmax)) at 20 degrees C increased from June to August and then decreased in September. The activation energy of V(cmax), a measure of the temperature dependence of V(cmax), was highest in summer, indicating that V(cmax) was most sensitive to leaf temperature at this time. The activation energy of V(cmax) was significantly correlated with growth temperature. Other parameters related to the temperature dependence of photosynthesis, such as intercellular CO(2) partial pressure and temperature dependence of RuBP regeneration capacity, showed no clear seasonal trend. It was suggested that leaf senescence affected the balance between carboxylation and regeneration of RuBP. The model simulation showed that photosynthetic rate and its optimal temperature were highest in summer. 相似文献
43.
Gap fellings are used to promote multi-cohort structures and to restore other natural forest structures and processes in protected areas that have been altered by anthropogenic activities. Gaps and felled trees may also provide breeding material for species that in high numbers can cause significant tree mortality, growth reduction and consequent economic losses in surrounding production forests. In this study, the effect of restoration gap fellings on feeding intensity of Tomicus spp. (pine shoot beetles) was evaluated by counting fallen pine shoots at different distances from gaps in a protected area in eastern Finland. Gap fellings had a clear effect on the feeding intensity of the beetles. The average density of fallen shoots m−2 was 17 within a 10-m distance from gaps but decreased rapidly to around 4 at the distance of 50 m and beyond. The distance decay in shoot feeding is described well by the negative exponential models. Our results suggest that gap fellings have only a localized effect on shoot feeding by Tomicus in the forests surrounding the restoration gaps. In practical restoration, a buffer zone of 100–200 m around the gap fellings, as implemented here, is enough to minimize economically significant growth reduction in surrounding production forests. As shown in this study, restoration of natural forest structures and dynamics to protect biodiversity is not necessarily in conflict with forest hygiene objectives in production forests. 相似文献
44.
Fisheries Science - To clarify the role of salt marsh creeks as fish refuges, predation risks for two small species (the nektonic Oryzias latipes and benthic Acanthogobius lactipes) were compared... 相似文献
45.
Karima Bouchemal Ryma Bouldjadj Mohamed Nadir Belbekri Nadia Ykhlef Abdelhamid Djekoun 《Archives of Agronomy and Soil Science》2017,63(5):710-722
Changes in enzymatic antioxidants and oxidative injury were evaluated in leaves of 10 wheat genotypes under drought, heat and paraquat (PQ) stress. The seedlings of wheat were germinated in plastic pots and grown in a greenhouse under semi-controlled conditions. Each treatment was performed at the 4th–5th leaf stage. Antioxidant enzyme activities catalase (CAT), guaiacol peroxidase (GPOX), lipid peroxidation (LPO), hydrogen peroxide (H2O2) production, chlorophyll content and cell membrane leakage were determined. Results indicated that the three treatments decreased membrane stability, chlorophyll content and increased the LPO, H2O2 content and activities of CAT and GPOX. The ANOVA analysis revealed significant differences between genotypes in response to the various treatments imposed. Wheat genotypes Bidi 17, Beliouni and Djennah khetifa showed the lowest LPO and H2O2 content and the highest total chlorophyll content, relative electrolyte leakage (REL), CAT and GPOX activities, while Colosseo, Waha, Vitron and Benisuif showed the lowest antioxidant defends, lowest REL and the highest H2O2 and MDA contents. Oued zenati, Beltagy and Bousselam showed intermediate response in terms of oxidative stress and antioxidant activity. 相似文献
46.
Hideaki Yamada Atsushi Nanami Itaru Ohta Kouki Fukuoka Taku Sato Masato Kobayashi Narisato Hirai Masayuki Chimura Yuichi Akita Yuuki Kawabata 《Fisheries Science》2012,78(4):809-818
The recruitment patterns of black-spot tuskfish Choerodon schoenleinii were compared with those of orange-dotted tuskfish (OT) C. ancholago. Individuals at the settlement and juvenile stages were collected using a push net in the intertidal zone and a seine net in seagrass beds. Relative values of standard length to total length (TL) for the two Choerodon species indicated an inflection point at approximately 10?C20?mm TL, suggesting that both species complete metamorphosis at a similar size. However, their temporal and spatial occurrence patterns were distinct. Newly settled individuals (postflexion stage) of black-spot tuskfish were collected mainly within foliage of Sargassum plants of the intertidal zone around March?CApril, while those of OT occurred in both the intertidal zone and seagrass beds mainly in May and June. In seagrass beds, the abundances of both species increased from May or June; however, the TL of black-spot tuskfish was bigger than that of OT. Therefore, black-spot tuskfish progressively migrate to seagrass beds after settling and completing metamorphosis in the intertidal zone, indicating that they utilize two different habitats as nursery grounds. Early spawning and migration from the intertidal zone by this species contributed to the occurrence of relatively large individuals in seagrass beds. 相似文献
47.
Masahiro Horinouchi Prasert Tongnunui Keisuke Furumitsu Yohei Nakamura Kouki Kanou Atsuko Yamaguchi Ken Okamoto Mitsuhiko Sano 《Fisheries Science》2012,78(3):577-587
To clarify the feeding habits of seagrass fishes, we examined the gut contents from 42 fish species collected in seagrass
habitats in Trang. Thirteen species showed ontogenetic and/or seasonal changes in food-use patterns. Smaller individuals generally
preyed on small planktonic items (e.g., copepod larvae) or small benthic/epiphytic crustaceans (e.g., harpacticoid copepods),
with subsequent changes to other prey items (e.g., shrimps, crabs, detritus and filamentous algae) with growth. The most important
dietary items for the seagrass fish assemblages comprised benthic/epiphytic crustaceans, detritus, and planktonic copepods.
Cluster analysis based on dietary overlaps showed that the seagrass fishes comprised eight feeding guilds (large benthic/epiphytic
crustacean, detritus, planktonic animal, small benthic/epiphytic crustacean, mollusc, invertebrate egg, polychaete, and fish
feeders). Of these, the first three guilds were the most abundantly represented, whereas the last three were each represented
by only a single species. 相似文献
48.
ABSTRACT: To clarify the feeding habits of tidal mudflat fishes, the gut contents of 29 fish species, collected from unvegetated tidal mudflats in Tokyo Bay, central Honshu, Japan, were examined. Ontogenetic changes in food preference were recognized in 21 species, including several of commercial importance (e.g. Acanthogobius flavimanus , Konosirus punctatus , Mugil cephalus cephalus , Plecoglossus altivelis altivelis , and Sardinella zunasi ). In general, larvae and/or juveniles of these species fed mainly on small zooplankton or benthic harpacticoid copepods, later switching to other prey items with growth (e.g. gammaridean amphipods, mysids, polychaetes, detritus, bivalves, and juvenile fishes). A cluster analysis based on dietary overlaps showed that the tidal mudflat fish assemblage comprised six feeding guilds (small benthic and epiphytic crustacean, zooplankton, detritus, mollusc, polychaete, and fish feeders). Of these, small benthic and epiphytic crustacean feeders were the most abundantly represented in the number of species. 相似文献
49.
Megumi ITOH Yasuhiro NAKAJIMA Kouki KUWANO Daisuke MAEDA Yoshie SAKURAI Yoshitaka MATSUI Satoshi KAWAMOTO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(2):193
We previously reported the possibility of using the electrocardiogram variable to estimate blood calcium (Ca) concentration in dairy cows based on the strong positive correlation between the blood Ca concentration and the inverse of the corrected ST peak interval (STc−1). To improve the accuracy of the estimation of blood Ca concentration, we investigated the relationship between blood Ca concentration and STc−1 for each postpartum day and available variables other than STc−1. We measured multiple variables (milk yield, calving number, age, body temperature, etc.), including serum total Ca concentration (tCa), blood ionized Ca concentration (iCa) and STc−1 in 462 Holstein cows on days 0, 1, 2, 3, 5, and 7 postpartum. A very high correlation was observed between iCa and tCa. The association between tCa and STc−1 for each postpartum day had a high coefficient of determination of 0.61–0.79 postpartum 0–2 days but decreased after the third day. In the investigation using the data from postpartum days 0–2, STc−1, heart rate interval, calving number, and age were highly correlated with tCa. In addition, a multiple regression equation was obtained with tCa as the objective variable and STc−1 and calving number as explanatory variables. The estimation accuracy was improved as compared with the simple regression equation using only STc−1 as the explanatory variable. This multiple regression equation was used for 11 cows suspected of having hypocalcemia, and it was able to correctly detect cows requiring early treatment, except for one cow. 相似文献
50.
Karima Bouchek-Mechiche Françoise Montfort Ueli Merz 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(2):277-287
Spongospora subterranea, f.sp. subterranea (Sss), which causes powdery scab, is mainly spread through infected seed tubers and survives in contaminated soil for many years.
The visual assessment of tuber lots by inspectors carries the risk of misidentification due to the difficulty of distinguishing
lesions caused by either Sss or Streptomyces spp.. To avoid this, the “Sss AgriStrip”, a rapid and lab-independent test tool based on a lateral flow immunoassay has been developed, and we assessed
its accuracy and sensitivity for detecting Sss. The Sss AgriStrip performed as well as other lab-based identification methods. The Sss AgriStrip, microscopy, ELISA, PCR, and real-time PCR techniques identified infection with S. subterranea in all tubers with typical powdery scab lesions. When lots with tubers showing a mixture of typical and atypical (suspicious)
symptoms were tested, the presence of S. subterranea was confirmed in all lesions by all methods. The DNA content was generally lower in atypical than in typical lesions. Diverse
and suspicious symptoms, which were difficult to assign to either powdery or common scab, tested negative with Sss AgriStrip and the other methods. This was despite microscopic observation of sporosori-like structures in some samples. Isolation
and molecular identification confirmed that these lesions were mostly caused by Streptomyces spp. The Sss AgriStrip is as sensitive as DAS-ELISA with a detection limit between 1 and 10 sporosori per ml buffer. It is ideal for rapid
and selective detection of Sss on farms and border inspection points to prevent spread of the pathogen. 相似文献