共查询到20条相似文献,搜索用时 46 毫秒
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Yunfei Jiang Rachid Lahlali Chithra Karunakaran Thomas D. Warkentin Arthur R. Davis Rosalind A. Bueckert 《Plant, cell & environment》2019,42(1):354-372
Field pea (Pisum sativum), a major grain legume crop, is autogamous and adapted to temperate climates. The objectives of this study were to investigate effects of high temperature stress on stamen chemical composition, anther dehiscence, pollen viability, pollen interactions with pistil and ovules, and ovule growth and viability. Two cultivars (“CDC Golden” and “CDC Sage”) were exposed to 24/18°C (day/night) continually or to 35/18°C for 4 or 7 days. Heat stress altered stamen chemical composition, with lipid composition of “CDC Sage” being more stable compared with “CDC Golden.” Heat stress reduced pollen viability and the proportion of ovules that received a pollen tube. After 4 days at 35°C, pollen viability in flower buds decreased in “CDC Golden,” but not in “CDC Sage.” After 7 days, partial to full failure of anthers to dehisce resulted in subnormal pollen loads on stigmas. Although growth (ovule size) of fertilized ovules was stimulated by 35°C, heat stress tended to decrease ovule viability. Pollen appears susceptible to stress, but not many grains are needed for successful fertilization. Ovule fertilization and embryos are less susceptible to heat, but further research is warranted to link the exact degree of resilience to stress intensity. 相似文献
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Short men are less likely to be married or live in a permanent relationship than their taller counterparts. This pattern is not due to their social status. While blue-collar workers are shorter on average than managers, the effects of height on finding a mate are similar in the two social groups. Being tall is also economically advantageous for men. With identical educational attainment levels, tall men have better careers than short men as they are given greater supervisory responsibilities. In making a commitment, some women might take height into account as an anticipated indicator of future resources of the household. Choice of partner is also influenced by social norms--i.e., partners should be physically well-matched--which is more difficult for shorter men. 相似文献
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Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons. 相似文献
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Tateyama Y Takano Y Tohno Y Moriwake Y Tohno S Hashimoto M Araki T 《Biological trace element research》2000,74(3):211-221
To show the relationships of calcium accumulation in the thoracic aorta to the other tissues, calcium contents were determined
with a microwave-induced plasma-atomic emission spectrometer on arteries, veins, cartilages, ligaments, and bones. These tissues
were resected from 18 individuals, consisting of 11 men and 7 women who died in the age range 59–91 yr. As thoracic and abdominal
aortas are routinely used for radiographic examination of arterial calcification, they appear to be standard tissues of the
calcium accumulation. The calcium accumulations were determined in the femoral artery, the superior and inferior venae cavae,
the internal jugular vein, cartilages of the articular disk of the temporomandibular joint and the intervertebral disk, both
the ligaments of the anterior cruciate ligament and the ligamentum capitis femoris, and the calcaneus, in contrast with the
thoracic aorta.
As calcium increased in the thoracic aorta, it increased in the femoral artery, the articular disk of the temporomandibular
joint, the intervertebral disk, both ligaments of the anterior cruciate ligament, and the ligamentum capitis femoris, but
it did not increase in veins, such as the superior and inferior venae cavae and the internal jugular vein. In contrast, it
decreased in the calcaneus. 相似文献
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Leslie M. Klevay 《Biological trace element research》1982,4(2-3):95-104
Meals of 12 diets were prepared from conventional foods with precautions against contamination by metallic elements because
of epidemiologic associations between ischemic heart disease and the metabolism of magnesium, calcium, copper, and zinc. Magnesium,
calcium, copper, and zinc were measured by atomic absorption spectrometry with satisfactory accuracy and precision.
The mean daily amount of copper in the diets was less than the apparent adult requirement. Mean amounts of magnesium and zinc
were close to apparent requirements; however, adults consuming amounts less than one standard deviation below these means
may be depleting body stores and be at risk of pathology.
Magnesium and copper were highly correlated (r=0.849,P=0.0001) in meals. This and other significant correlations probably will prevent the relationships of these elements to ischemic
heart disease from being elucidated by epidemiology. Metabolic experiments will be necessary to differentiate among several
hypotheses. 相似文献
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Dennis R. Lassuy 《Environmental Biology of Fishes》1984,10(3):183-193
Synopsis Analysis of stomach contents of Stegastes lividus revealed a shift from omnivory in juveniles to herbivory in adults. Red algae, primarily Polysiphonia spp., Gelidiopsis intricata and Ceramium spp., formed the bulk of the diet in all size classes. Foraminifera and small crustaceans were of particular importance in the diet of juveniles. Net nitrogen assimilation efficiency of field-fed S. lividus was approximately 61%, and did not vary with fish size. The net assimilation efficiencies of fish fed on Enteromorpha in the laboratory ranged from size-class means of 36–79% for nitrogen and from 29–72% for total organic material, and increased from juveniles to adults. Apparently, juveniles compensate for a lower efficiency in assimilating plant food by including a higher percentage of animal material in their natural diets. The ratios of intestine length to standard length (IL/SL) and to intestine diameter (IL/ID) increased rapidly in juveniles and leveled off in adults. The retention time for ingested food items may only be about one-half as long in juveniles as in adults. The combination of observed IL/ID ratios and estimated retention times proved most valuable in the interpretation of ontogenetic changes in feeding habits and assimilation efficiency. 相似文献
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Shizuka Tanaka Yoko Aoki Yohei Matoba Kazue Yahagi Tsutomu Itagaki Yoko Matsuzaki Katsumi Mizuta 《Microbiology and immunology》2016,60(12):854-858
To clarify the seroepidemiology of human parechovirus type 1 (HPeV1), 3 and 6, neutralizing antibodies (NT Abs) were measured in 214 serum specimens collected in 2014 in Yamagata, Japan. The seroprevalence against HPeV1 was 100% in all age groups, while that against HPeV3 and HPeV6 was 79.4% and 66.8%, respectively, overall. The geometric mean titers of NT Abs against HPeV1, 3 and 6 were 755.2, 255.0 and 55.9, respectively, overall. Our findings indicate that HPeV1 is the most prevalent HPeV circulating in Yamagata, followed by HPeV3 and HPeV6. 相似文献
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Pregnant women in developing countries are vulnerable to multiple micronutrient deficiencies. Studies assessing serum levels
of the micronutrients and magnitude of their deficiencies are very scarce in African subjects. This study was aimed at determining
serum levels of micronutrients in 375 pregnant (42 HIV seropositive) and 76 non-pregnant women (20 HIV seropositive) who visited
the University of Gondar Hospital, Gondar, Ethiopia. Serum concentrations of zinc,\ copper, selenium, calcium, and magnesium
were determined using an inductively coupled plasma mass spectrometer. Irrespective of HIV serostatus, pregnant women had
significantly higher serum concentrations of copper and copper/zinc ratio and significantly lower magnesium compared to those
in non-pregnant women (P < 0.05). Except for selenium, which was significantly lower in HIV-seropositive pregnant women (P < 0.05), the mean serum concentrations of zinc, copper, calcium, and magnesium were not significantly different between pregnant
women by HIV serostatus. The prevalence of deficiency in zinc, magnesium, selenium, and calcium in the pregnant women, irrespective
of their HIV serostatus, was 66.7%, 25.6%, 21.9%, and 9.3%, respectively. The magnitude of deficiency in zinc, magnesium,
and selenium was significantly higher in HIV seropositive pregnant women (76.2%, 52.4%, and 45.2%) than that in HIV-seronegative
pregnant women (65.5%, 22.2%, and 18.9%) and in HIV-seronegative non-pregnant women (42.9%, 8.1%, and 30.4%; P < 0.05). Deficiency in one, two, three, or four mineral elements was observed in 44.8%, 14.4%, 9.9%, and 5.1% of the pregnant
women, respectively. Only 25.9% of the pregnant women and 44.7% of the non-pregnant women were not deficient in any of the
micronutrients. The high prevalence of micronutrient deficiencies in pregnant and non-pregnant women in Gondar, Ethiopia warrants
the need for strategies on prevention and control of the deficiencies. 相似文献
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Summary. The article is reviewing some significant features and issues in the process of haploid formation in two important monocotyledonous
crop plants – maize and barley – and in two dicotyledonous plants – flax and potato. Exotic maize lines with higher androgenic
response turned up as a good source for this heritable trait and this valuable trait can be incorporated into elite maize
lines via crossing. Lots of attempts were devoted to identifying some cytological and/or morphological markers for androgenic
response in maize microspore cultures. The “starlike” organization of the cytoplasm inside the induced maize microspores together
with the enlarged size of induced microspores can be considered as morphological markers for androgenic response. In barley,
microspores with rich cytoplasm that was of granular appearance with the nucleus located near the cell wall and with no visible
vacuole had the largest survival rate and many of these cells continued in development and produced embryos. In flax, a dramatic
increase of induction rate in anther cultures (up to 25%) was achieved when flax anthers were pretreated for 3 days at 4 °C
and afterwards kept for 1 day at 35 °C. Also gynogenesis in flax has been reported already and complete plants were obtained.
In potato microspore cultures, formation of two dissimilar cells indicated a strong polarization in the system and as a result
of this polarization a prominent suspensor developed that persisted until the torpedo stage of the androgenic embryo. This
was the first time the formation of a well developed suspensor was described in connection with androgenesis.
Correspondence and reprints: Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, P.O. Box 39A, 950
07 Nitra, Slovak Republic. 相似文献
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Stephen Phillip Easley Anthony M. Coelho Linda L. Taylor 《American journal of primatology》1987,13(4):397-411
This paper reports a study designed to test the hypothesis that a relationship exists among dominance rank, tension, and scratch behaviors in anubis baboons (Papio cynocephalus anubis). Our study was conducted on two groups of male baboons, each containing eight unrelated individuals who were approximately 6 years of age and who shared common rearing histories. Focal animal sampling was used to collect behavioral data. Hand scratching, foot scratching, avoid, tension, allogrooming, autogrooming, and manipulation were measured as acts performed per hour of sampling. Dominance matrices were constructed based on net difference of avoid behavior performed and received (adjusted for time sampled). Individual status ranks were grouped into two status classes, high and low. Analysis of variance models demonstrated significant differences in the performance rate of scratching behaviors by dominance rank class, as well as differences in scratching performance by tension class. Individuals in the high status class had significantly higher rates of total scratching, hand scratching, foot scratching, and tension behavior performance than their counterparts in the low status class. No significant difference was found between status classes or tension classes for performance rate of allogrooming, autogrooming, or manipulation behavior. The frequency of scratching and general level of activity were not significantly correlated. The results are interpreted to indicate the possibility that scratching may function as a displacement behavior, which subjectively appears to communicate heightened frustration, anxiety, or arousal. 相似文献
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Asli Mehdi Azizzadeh Mohammad Moghaddamjafari Amir Mohsenzadeh Mohammad 《Biological trace element research》2020,193(2):390-399
Biological Trace Element Research - Obesity is a major public health problem worldwide and a risk factor for certain diseases, including cardiovascular disease, diabetes, cancer, and depression.... 相似文献
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Biodiversity conservation,yield, and alternative products in coffee agroecosystems in Sumatra,Indonesia 总被引:1,自引:0,他引:1
Agroecology and conservation must overlap to protect biodiversity and farmer livelihoods. Coffee agroecosystems with complex
shade canopies protect biodiversity. Yet, few have examined biodiversity in coffee agroecosystems in Asia relative to the
Americas and many question whether coffee agroecosystems can play a similar role for conservation. We examined vegetation,
ant and bird diversity, coffee yields and revenues, and harvest of alternative products in coffee farms and forests in SW
Sumatra, Indonesia near Bukit Barisan Selatan National Park (BBS). BBS is among the last habitats for large mammals in Sumatra
and >15,000 families illegally cultivate coffee inside of BBS. As a basis for informing management recommendations, we compared
the conservation potential and economic outputs from farms inside and outside of BBS. Forests had higher canopy cover, canopy
depth, tree height, epiphyte loads, and more emergent trees than coffee farms. Coffee farms inside BBS had more epiphytes
and trees and fewer coffee plants than farms outside BBS. Tree, ant, and bird richness was significantly greater in forests
than in coffee farms, and richness did not differ in coffee farms inside and outside of BBS. Species similarity of forest
and coffee trees, ants, and birds was generally low (<50%). Surprisingly, farms inside the park were significantly older,
but farm size, coffee yields, and revenues from coffee did not depend on farm location. Farmers outside BBS received higher
prices for their coffee and also more often produced other crops in their coffee fields such that incentives could be created
to draw illegal farmers out of the park. We also discuss these results with reference to similar work in Chiapas, Mexico to
compare the relative contribution of coffee fields to conservation in the two continents, and discuss implications for working
with farmers in Sumatra towards conservation plans incorporating sustainable coffee production. 相似文献
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A library of 4,6-dihydroxypyrimidine diones (1–35) were synthesized and evaluated for their urease inhibitory activity. Structure-activity relationships, and mechanism of inhibition were also studied. All compounds were found to be active with IC50 values between 22.6 ± 1.14–117.4 ± 0.73 µM, in comparison to standard, thiourea (IC50 = 21.2 ± 1.3 µM). Kinetics studies on the most active compounds 2–7, 16, 17, 28, and 33 were performed to investigate their modes of inhibition, and dissociation constants Ki. Compounds 2, 3, 7, 16, 28, and 33 were found to be mixed-type of inhibitors with Ki values in the range of 7.91 ± 0.024–13.03 ± 0.013 µM, whereas, compounds 4–6, and 17 were found to be non-competitive inhibitors with Ki values in the range of 9.28 ± 0.019–13.05 ± 0.023 µM. In silico study was also performed, and a good correlation was observed between experimental and docking studies. This study is continuation of our previously reported urease inhibitory activity of pyrimidine diones, representing potential leads for further research as possible treatment of diseases caused by ureolytic bacteria. 相似文献