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1.
MITSUHIRO MATSUO HIDEKI MICHINAGA HIROYUKI TERAO EIJI TSUZUKI 《Weed Biology and Management》2004,4(3):148-153
Seed germination, seedling emergence, and the morphological characteristics of juvenile seedlings of Commelina benghalensis L. were observed. For aerial seeds collected in September and October, seedling emergence peaked in April and June for large seeds and from June to August for small seeds, whereas seedling emergence for large seeds collected in November showed peaks in March and April under natural rainfall conditions, and in April and June under irrigation conditions. Seedlings from small seeds emerged intermittently over a longer period from April to August under both conditions. Aerial seeds of C. benghalensis germinated on wet filter paper on the second day after seeding (DAS) for large seeds and the fourth DAS for small seeds. The germination percentage for large seeds was higher than that for small seeds by the 14th DAS. The germination percentage for large aerial seeds showed no significant difference between light and dark conditions. However, the percentage for small aerial seeds was higher under light than under dark conditions. Seedlings from large aerial seeds emerged on the third DAS at 0–50 mm soil depths. The percentage of emergence at 0 and 1 mm soil depths increased until the 30th DAS, whereas those at soil depths of 5–50 mm showed no change after the 9th DAS. There was no emergence at a soil depth of 100 mm. Seedlings from small aerial seeds emerged on the 6th DAS at 0–1 mm soil depths, with the percentage increasing until the 30th DAS. Although seedlings at 5 and 10 mm soil depths also emerged on the 6th DAS, there was no change in the percentage after the 12th DAS. There was no emergence at soil depths of 20–100 mm. The hypocotyl and taenia (part of the cotyledon connected to the seed) in juvenile seedlings that emerged from soil depths of 50 mm were longer than those in seedlings emerging from a soil depth of 1 mm. 相似文献
2.
There are concerns that genetically modified soybean might threaten the genetic diversity of the wild soybean populations that are distributed in East Asia because genetically modified soybean has no crossing barrier with wild soybean. A simple and effective method to prevent hybridization via pollen flow is spatial separation between the two species because their hybridization occurs only when they grow in close proximity. Therefore, the invasiveness of wild soybean needs to be known in order to secure the appropriate distances. As wild soybean seeds are dispersed mechanically by pod dehiscence, an experiment was conducted in which white sheets were placed on the ground, concentric circles were drawn around the parent plants, and the number of dispersed seeds within each 0.5 m‐wide zone were counted. About 40% of the produced seeds were dispersed and the number of dispersed seeds gradually declined as the distance from the parent plants increased. The model that explained the relationship between the number and distance of the dispersed seeds was produced by using a generalized linear model procedure. More than 95, 99, and 99.9% of the produced seeds stayed within 3.5, 5.0, and 6.5 m after natural pod dehiscence. Knowing these values is useful for evaluating the level of invasive risk by mechanical seed dispersal. The goal of the work is to efficiently and deliberately prevent hybridization by isolating genetically modified soybean fields and wild soybean populations by vegetation management, including weeding and setting up specific‐width buffer zones. 相似文献
3.
The development of juvenile seedlings of Monochoria vaginalis (Burm.f.) Kunth var. vaginalis concerning its hypocotyl hairs was investigated morphologically at establishing on 1 mm flooded paddy soil surface and in distilled water. Prime germination of M. vaginalis seeds sown after breaking dormancy was found on a flooded paddy soil surface and in distilled water at 6 h after seeding (HAS). Elongation of cotyledons and hypocotyl hairs of juvenile seedlings appeared at 12 HAS on a paddy soil surface, while lengths of hypocotyl hairs were almost the same as longitudinal length of seeds and cotyledons formed arch on the soil surface at 18 HAS. Seminal roots began to emerge and seedlings adhered completely to the soil surface by hypocotyl hairs, which were longer in length than seminal roots at 24 HAS. At 36 HAS, seed chaffs completely separated from the soil surface, as cotyledons had elongated from standing up, and lengths of seminal roots became longer than those of hypocotyl hairs. Emergence of first leaves and crown roots was simultaneously observed at 48 HAS. Elongations of cotyledons, seminal roots and hypocotyl hairs were completely terminated at 96, 120 HAS and 120 HAS respectively, and the elongation of 2 to 4 crown roots was observed at 120 HAS. Almost half the number of hypocotyl hairs putrefied at 240 HAS. In distilled water, hypocotyl hairs elongated to their longest at 36 HAS earlier than those on a paddy soil surface. It was concluded that hypocotyl hairs supported a strongly physical mechanism in establishing M. vaginalis seedlings on a paddy soil surface. 相似文献
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Tsukasa WAKI Yuma OHARI Kei HAYASHI Junji MORIBE Kayoko MATSUO Yasuhiro TAKASHIMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(6):957
Trematodes of the genus Dicrocoelium are one of the most common parasites in ruminant animals; however, their life cycles in Japan are unclear. To find the sporocysts of D. chinensis in the natural field, we sampled 269 land snails (14 species) at a location with high level infection of sika deer in Gifu Prefecture, Honshu Island, Japan in autumn between 2017 and 2019. During the sampling period, we found mother sporocysts in the hepatopancreas of Aegista vulgivaga and Cyclophorus herklotsi. DNA barcoding based on the sequences of cytochrome c oxidase subunit 1 showed that the sporocysts from A. vulgivaga belonged to D. chinensis, indicating that this snail has potential as the first intermediate host of D. chinensis at this location. 相似文献
6.
ABSTRACT: Developmental changes of swimming speed were analysed in the chub mackerel Scomber japonicus raised on two distinct dietary regimens. One group was fed only zooplankton such as rotifers and Artemia nauplii (R group) and the other group was fed rotifers plus red sea bream Pagrus major larvae (Pm group). Fish from the Pm group grew faster than those from the R group, and both the cruise and burst swimming speeds were faster for the Pm group even when match-sized comparisons were made. Fish in the Pm group attained a standard length (SL) of 17.5 mm by day 14 and their cruise and burst swimming speeds were 5.39 SL/s and 18.45 SL/s, whereas the R group attained 17.35 mm SL by day 17 and their cruise and burst swimming speeds were 4.28 SL/s and 13.98 SL/s. The results suggest that the swimming speed of chub mackerel in the wild would develop differently depending on the food resources they happen to encounter. 相似文献
7.
TRAN DANG XUAN EIJI TSUZUKI HIROYUKI TERAO MITSUHIRO MATSUO TRAN DANG KHANH SEIICHI MURAYAMA NGUYEN HUU HONG 《Weed Biology and Management》2003,3(2):137-144
Two alfalfa varieties, namely Rasen and Yuba , and rice by-products of Koshihikari ( Oryza sativa L. cv. Japonica ), including hull and bran were used for weed control in rice. Rasen and Yuba were sequentially evaluated to have the strongest allelopathic potential among eight common alfalfa varieties in Japan. Rasen , Yuba and rice by-products in a laboratory experiment exhibited suppression of emergence of lettuce ( Lactuca sativa L.), barnyardgrass ( Echinochloa oryzicola Vasing.), and monochoria ( Monochoria vaginalis Presl var. plantaginea Solms-Laub.). In a paddy field experiment, at 15 days after application, a dose of 1 ton ha−1 of alfalfa, rice by-products and the incorporated alfalfa-rice by-products significantly inhibited weed growth and reduced weed species, except for rice bran. However, at 40 days after application, the greatest weed control was sequentially recorded with Yuba (95.2%), Rasen (90.5%) and the incorporated Rasen -hull (88.3%). Rice hull exhibited stronger (51.7%) weed control than the negligible weed control of rice bran (25.1%). Inhibition of both Rasen and Yuba on weed emergence after application became more vigorous, whereas those of rice by-products were gradually devitalized. Rasen had a maximum increase of rice yield (80.6%) compared to the control and it was slightly higher (9.6%) than the herbicide treatment. Findings showed that Rasen was the most promising material for weed control among those studied. Results denoted that weed control capability of allelopathic materials had an impetuous effect on rice growth and yield. 相似文献
8.
NGUYEN HUU HONG TRAN DANG XUAN TSUZUKI EIJI MITSUHIRO MATSUO OGUSHI YUICHI 《Weed Biology and Management》2002,2(3):143-147
Kava is a perennial pepper plant from the Oceanic region, which is commonly used as a drink by natives and for pharmacological purposes. Results of this study concluded that Kava has allelopathic potential and suppressed germination and growth of lettuce ( Lactuca sativa L), barnyardgrass ( E. crus-galli Beauv var. formosensis Ohwi.), and duck-tongue weed ( M. vaginalis Presl var. plantaginea Solms-Laub.) Moreover, Kava inhibited emergence of weeds in paddy soils. The inhibition of Kava became stronger as the applied concentration increased. In a greenhouse experiment, Kava had the greatest inhibition on emergence and weed growth in paddy soils when a dose of 1 ton ha−1 of Kava was divided and applied at 3, 16, and 23 days after watering. Inhibition by Kava varied among weed species. Results from this study suggest that Kava might be useful for weed control in rice or reduce dependence on herbicide. 相似文献
9.
Yuria UMEMURA Ryosuke MIYAMOTO Rie HASHIMOTO Kyoko KINOSHITA Takuya OMOTEHARA Daichi NAGAHARA Tetsushi HIRANO Naoto KUBOTA Kiichi MINAMI Shogo YANAI Natsumi MASUDA Hideto YUASA Youhei MANTANI Eiko MATSUO Toshifumi YOKOYAMA Hiroshi KITAGAWA Nobuhiko HOSHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(12):1587-1598
Mammalian sexual fate is determined by the presence or absence of sex determining
region of the Y chromosome (Sry) in the “bipotential” gonads.
Recent studies have demonstrated that both male and female sexual development are induced
by distinct and active genetic pathways. Breeding the Y chromosome from Mus m.
domesticus poschiavinus (POS) strains into C57BL/6J (B6J) mice
(B6J-XYPOS) has been shown to induce sex reversal (75%: bilateral ovary, 25%:
true hermaphrodites). However, our B6N-XYPOS mice, which were generated by
backcrossing of B6J-XYPOS on an inbred B6N-XX, develop as males (36%: bilateral
testis with fertility as well as bilateral ovary (34%), and the remainder develop as true
hermaphrodites. Here, we investigated in detail the expressions of essential sex-related
genes and histological features in B6N-XYPOS mice from the fetal period to
adulthood. The onsets of both Sry and SRY-box 9 (Sox9) expressions as determined
spatiotemporally by whole-mount immunohistochemistry in the B6N-XYPOS gonads
occurred 2–3 tail somites later than those in B6N-XYB6 gonads, but earlier than
those in B6J-XYPOS, respectively. It is possible that such a small difference
in timing of the Sry expression underlies testicular development in our
B6N-XYPOS. Our study is the first to histologically show the expression and
ectopic localization of a female-related gene in the XYPOS testes and a
male-related gene in the XYPOS ovaries. The results from these and previous
experiments indicate that the interplay between genome variants, epigenetics and
developmental gene regulation is crucial for testis development. 相似文献
10.
Tetsushi HIRANO Shogo YANAI Takuya OMOTEHARA Rie HASHIMOTO Yuria UMEMURA Naoto KUBOTA Kiichi MINAMI Daichi NAGAHARA Eiko MATSUO Yoshiko AIHARA Ryota SHINOHARA Tomoyuki FURUYASHIKI Youhei MANTANI Toshifumi YOKOYAMA Hiroshi KITAGAWA Nobuhiko HOSHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1207-1215
Neonicotinoids, some of the most widely used pesticides in the world, act as agonists to
the nicotinic acetylcholine receptors (nAChRs) of insects, resulting in death from
abnormal excitability. Neonicotinoids unexpectedly became a major topic as a compelling
cause of honeybee colony collapse disorder, which is damaging crop production that
requires pollination worldwide. Mammal nAChRs appear to have a certain affinity for
neonicotinoids with lower levels than those of insects; there is thus rising concern about
unpredictable adverse effects of neonicotinoids on vertebrates. We hypothesized that the
effects of neonicotinoids would be enhanced under a chronic stressed condition, which is
known to alter the expression of targets of neonicotinoids, i.e.,
neuronal nAChRs. We performed immunohistochemical and behavioral analyses in male mice
actively administered a neonicotinoid, clothianidin (CTD; 0, 10, 50 and 250 mg/kg/day),
for 4 weeks under an unpredictable chronic stress procedure. Vacuolated seminiferous
epithelia and a decrease in the immunoreactivity of the antioxidant enzyme glutathione
peroxidase 4 were observed in the testes of the CTD+stress mice. In an open field test,
although the locomotor activities were not affected, the anxiety-like behaviors of the
mice were elevated by both CTD and stress. The present study demonstrates that the
behavioral and reproductive effects of CTD become more serious in combination with
environmental stress, which may reflect our actual situation of multiple exposure. 相似文献