期刊文献+
共找到952篇文章
< 1 2 48 >
每页显示 20 50 100
Stage IV malignant transformation of mature cystic teratoma palliatively treated with concurrent chemoradiotherapy:A case report
1
作者 Saori Kondo Takashi Suzuki +4 位作者 Kanato Yoshiike Sakura Yamanaka Kenta Sonehara Hiroshi Nabeshima Osamu Oguchi 《World Journal of Clinical Cases》 SCIE 2025年第1期56-61,共6页
BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced cases.Concurrent chemoradiotherapy(CCRT)has an inhibitory effect on MT.CASE SUMMARY Herein,we present a ... BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced cases.Concurrent chemoradiotherapy(CCRT)has an inhibitory effect on MT.CASE SUMMARY Herein,we present a case in which CCRT had a reduction effect preoperatively.A 73-year-old woman with pyelonephritis was referred to our hospital.Computed tomography revealed right hydronephrosis and a 6-cm pelvic mass.Endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB)revealed squamous cell carci-noma.The patient was diagnosed with MT of MCT.Due to her poor general con-dition and renal malfunction,we selected CCRT,expecting fewer adverse effects.After CCRT,her performance status improved,and the tumor size was reduced;surgery was performed.Five months postoperatively,the patient developed dis-semination and lymph node metastases.Palliative chemotherapy was ineffective.She died 18 months after treatment initiation.CONCLUSION EUS-FNB was useful in the diagnosis of MT of MCT;CCRT suppressed the disea-se and improved quality of life. 展开更多
关键词 mature cystic teratoma Malignant transformation Squamous cell carcinoma Concurrent chemoradiotherapy Endoscopic ultrasound-guided fine-needle biopsy Case report
下载PDF
A New Micropropagation Technology of Tilia amurensis:In VitroMicropropagation of Mature Zygotic Embryos and the Establishment of a PlantRegeneration System
2
作者 Shijie Lin Zimo Wang +8 位作者 Hongbo Zhu Conghui Wang Hongfeng Wang Dawei Zhang Tianbing Gou Guangdao Bao Ye Luo Huaijiang He Zhonghui Zhang 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第2期277-289,共13页
Tilia amurensis is an economically valuable broadleaf tree species in Northeast China.The production of highqualityT.amurensis varieties at commercial scales has been greatly limited by the low germination rates.There... Tilia amurensis is an economically valuable broadleaf tree species in Northeast China.The production of highqualityT.amurensis varieties at commercial scales has been greatly limited by the low germination rates.Thereis thus a pressing need to develop an organogenesis protocol for in vitro propagation of T.amurensis to alleviate ashortage of high-quality T.amurensis seedlings.Here,we established a rapid in vitro propagation system forT.amurensis from mature zygotic embryos and analyzed the effects of plant growth regulators and culture mediain different stages.We found that Woody plant medium(WPM)was the optimal primary culture medium formature zygotic embryos.The highest callus induction percentage(68.76%)and number of axillary buds induced(3.2)were obtained in WPM+0.89μmol/L 6-benzyladenine(6-BA)+0.46μmol/L kinetin(KT)+0.25μmol/Lindole-3-butryic acid(IBA)+1.44μmol/L gibberellin A_(3)(GA_(3)).The multiple shoot bud development achievedthe highest percentage(83.32%)in the Murashige and Skoog(MS)+2.22μmol/L 6-BA+0.25μmol/L IBA+1.44μmol/L GA_(3).The rooting percentage(96.70%)was highest in 1/2 MS medium+1.48μmol/L IBA.Thesurvival percentage of transplanting plantlets was 82.22%in soil:vermiculite:perlite(5:3:1).Our study is the firstto establish an effective organogenesis protocol for T.amurensis using mature zygotic embryos. 展开更多
关键词 Tilia amurensis Rupr. mature zygotic embryo MICROPROPAGATION adventitious bud multiplication ROOTING
下载PDF
Enhancing economic sustainability in mature oil fields:Insights from the clustering approach to select candidate wells for extended shut-in
3
作者 B.Lobut E.Artun 《Artificial Intelligence in Geosciences》 2024年第1期173-188,共16页
Fluctuations in oil prices adversely affect decision making situations in which performance forecasting must be combined with realistic price forecasts.In periods of significant price drops,companies may consider exte... Fluctuations in oil prices adversely affect decision making situations in which performance forecasting must be combined with realistic price forecasts.In periods of significant price drops,companies may consider extended duration of well shut-ins(i.e.temporarily stopping oil production)for economic reasons.For example,prices during the early days of the Covid-19 pandemic forced operators to consider shutting in all or some of their active wells.In the case of partial shut-in,selection of candidate wells may evolve as a challenging decision problem considering the uncertainties involved.In this study,a mature oil field with a long(50+years)production history with 170+wells is considered.Reservoirs with similar conditions face many challenges related to economic sustainability such as frequent maintenance requirements and low production rates.We aimed to solve this decision-making problem through unsupervised machine learning.Average reservoir characteristics at well locations,well production performance statistics and well locations are used as potential features that could characterize similarities and differences among wells.While reservoir characteristics are measured at well locations for the purpose of describing the subsurface reservoir,well performance consists of volumetric rates and pressures,which are frequently measured during oil production.After a multivariate data analysis that explored correlations among parameters,clustering algorithms were used to identify groups of wells that are similar with respect to aforementioned features.Using the field’s reservoir simulation model,scenarios of shutting in different groups of wells were simulated.Forecasted reservoir performance for three years was used for economic evaluation that assumed an oil price drop to$30/bbl for 6,12 or 18 months.Results of economic analysis were analyzed to identify which group(s)of wells should have been shut-in by also considering the sensitivity to different price levels.It was observed that wells can be characterized in the 3-cluster case as low,medium and high performance wells.Analyzing the forecasting scenarios showed that shutting in all or high-and medium-performance wells altogether results in better economic outcomes.The results were most sensitive to the number of active wells and the oil price during the high-price period.This study demonstrated the effectiveness of unsupervised machine learning in well classification for operational decision making purposes.Operating companies may use this approach for improved decision making to select wells for extended shut-in during low oil-price periods.This approach would lead to cost savings especially in mature fields with low-profit margins. 展开更多
关键词 Unsupervised learning CLUSTERING mature oil fields Extended shut-in Well classification
下载PDF
Callus Induction and Plant Regeneration from Mature Seeds of Perennial Ryegrass 被引量:15
4
作者 曾升坚 卞建春 +2 位作者 方钲 张冬霞 邹新海 《Agricultural Science & Technology》 CAS 2009年第6期33-36,共4页
Objective The aim was to explore callus induction and plant regeneration of perennial ryegrass, as well as provide the foundation for transgenic research on perennial ryegrass.[ Methed] Mature seeds of perennial ryegr... Objective The aim was to explore callus induction and plant regeneration of perennial ryegrass, as well as provide the foundation for transgenic research on perennial ryegrass.[ Methed] Mature seeds of perennial ryegrass were used as explants to study the effects of different hormone compositions on callus induction, proliferation and plant differentiation. Result The result showed that the induction rate achieved its highest on 2,4-D of 8 mg/L combining with 6-BA of 0.025 mg/L, which was up to 56.42%. Callus were differentiated after two to three generations, the highest differentiation rate 34.14% was achieved in the medium contained MS medium with 6-BA of 2 mg/L, and the differentiation rate was obviously affected by the callus condition after proliferation. The root inducing medium, containing 0.5 mg/L NAA and MS medium with half of macroelement, gained 98% root inducing rate. Conclusien A high frequency genetic regeneration system was established. 展开更多
关键词 Perennial ryegrass mature seed: Tissue culture Plant regeneration
下载PDF
Effects of Genotypes and Basic Medium on Culture of Maize Mature Embryos 被引量:4
5
作者 周晓馥 吕杰 +2 位作者 未晓巍 赵卓 徐洪伟 《Agricultural Science & Technology》 CAS 2011年第8期1136-1138,共3页
[Objective]This study was to screen out suitable genotypes and basic medium for the culture of maize mature embryos.[Method]Using mature embryos of nine maize genotypes as explants,the effects of genotypes and basic m... [Objective]This study was to screen out suitable genotypes and basic medium for the culture of maize mature embryos.[Method]Using mature embryos of nine maize genotypes as explants,the effects of genotypes and basic medium on callus induction and subculture were investigated.[Result]The genotypes performed better in callus induction and subculture were found in turn 853-35,853-209,Dan 34 and 81162.MS medium is better than N6 medium in the callus induction from maize embryos,while N6 medium is more suitable for callus subculture.[Conclusion]Our study further improved the tissue culture system in maize with mature embryos as explants. 展开更多
关键词 MAIZE mature embryos GENOTYPE Basic culture medium Callus induction
下载PDF
Callus Induction from Mature Embryos of Maize 被引量:9
6
作者 肖莉杰 王丽艳 闵丽 《Agricultural Science & Technology》 CAS 2009年第6期67-68,93,共3页
In this study we studied the factors influencing the callus induction from mature embryos of maize inbred lines Qi 319, Zhen 58, Chang 7 -2, Lx 9801 and 81162, such as genotype, combination of plant growth regulators,... In this study we studied the factors influencing the callus induction from mature embryos of maize inbred lines Qi 319, Zhen 58, Chang 7 -2, Lx 9801 and 81162, such as genotype, combination of plant growth regulators, and low-temperature pretreatment. The results showed that the induction rate of Qi 319 was the highest among the four genotypes tested; combination of 4.0 mg/L 2,4-D + 0.5 mg/L 6-BA was suitable for inducing callus from mature embryos; three days of 4℃ pretreatment can promote the callus induction significantly. The indices optimized in the present study are helpful for establishing genetic transformation system in maize without considering seasonal variation. 展开更多
关键词 MAIZE mature embryos Callus induction
下载PDF
Optimizing Yanbian Cow Oocytes Mature in vitro and Cleavage System after Nuclear Transfer Based on Uniform Design 被引量:6
7
作者 苗婷婷 魏世宝 《Agricultural Science & Technology》 CAS 2009年第5期113-115,共3页
[Objective] The aim was to optimize Yanbian cow oocytes mature in vitro and cleavage system after nuclear transfer based on uniform design. [Method] Oocytes were recovered by aspiration method, and oocytes were mature... [Objective] The aim was to optimize Yanbian cow oocytes mature in vitro and cleavage system after nuclear transfer based on uniform design. [Method] Oocytes were recovered by aspiration method, and oocytes were matured in vitro (IVM) with different conditions, and then carried out nucleus transfer, fusion, activation and in vitro culture (IVC) of embryo. Effects of ovary storage temperature, maturation time and follicular diameter size on in vitro maturation and cleavage rates of cow oocytes were compared. [ Result] The best conditions of IVM of Yanbian cow oocytes was that: the oocytes of 8 mm diameter were matured in vitro for 24 hours when the ovaries were stored at 26℃ or 31 ℃. The best cleave conditions after nucleus transfer of oocytes was that: the oocytes of 6 mm or 8 mm diameter were cultured in vitro for 24 hours when the ovaries were stored at 26℃. [ Conclusion] The result has some reference to Yanbian cow and other cow breeding and population expanding propagation. 展开更多
关键词 Uniform design Yanbian cow OOCYTES mature CLEAVAGE
下载PDF
Comparison in effect of different metal ions, pH and reducing agent on the protease activity in human hyper mature and mature cataract 被引量:1
8
作者 SAMI Amtul Jamil SAMI Amtul Naseer KANWAL Noreen 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2007年第8期599-603,共5页
This study was undertaken to isolate and characterize the protease activity of human eye lens sample of mature and hyper mature cataract. Samples were collected just after surgery of the cataract lens and were stored ... This study was undertaken to isolate and characterize the protease activity of human eye lens sample of mature and hyper mature cataract. Samples were collected just after surgery of the cataract lens and were stored at -20 ℃. The total protein extract was isolated from 5 samples in each case (mature and hyper mature cataract) and clear supernatant obtained after centrifugation was used as an enzyme source. The optimum pH for the proteases of mature cataract was 7.5 while the proteases of hyper mature cataract were recorded for maximum activity at pH 5.5 and 7.5. The optimum temperature for both enzyme sources was 50 ℃. Effect of different metal ions such as potassium, lead, silver, zinc and borate was studied. In each case protease activity was increased. Reducing agent e.g. β mercaptoethanol also caused an increase in activity indicating the involvement of sulfhydryl groups. Protease activity was also located on agar plates. 展开更多
关键词 mature cataract Hyper mature cataract Eye lens Protease activity β mercaptoehanol
下载PDF
Transcript Profiling Reveals Abscisic Acid,Salicylic Acid and Jasmonic-Isoleucine Pathways Involved in High Regenerative Capacities of Immature Embryos Compared with Mature Seeds in japonica Rice 被引量:1
9
作者 XIAO Kaizhuan MAO Xiaohui +5 位作者 WANG Yingheng WANG Jinlan WEI Yidong CAI Qiuhua XIE Hua'an ZHANG Jianfu 《Rice science》 SCIE CSCD 2018年第4期227-234,共8页
Induced pluripotent cell mass plays a role in genetic transformation mediated by Agrobacterium. Mature seeds are more recalcitrant to the induction of suitable calli than immature embryos in rice, but the exact molecu... Induced pluripotent cell mass plays a role in genetic transformation mediated by Agrobacterium. Mature seeds are more recalcitrant to the induction of suitable calli than immature embryos in rice, but the exact molecular mechanisms involved remain elusive. In this study, the morphological structure of calli induced from mature seeds and immature embryos were observed under a scanning electron microscope using a paraffin embedded technique. Meanwhile, a total of 2 173 up- and down-regulated genes were identified in calli induced from mature seeds and immature embryos by RNA-seq technique and furtherly confirmed by quantitative real-time PCR. The results revealed the remarkable morphological differences in calli induced from mature seeds and immature embryos, and plant hormone signal transduction and hormone biosynthesis pathways, such as abscisic acid, salicylic acid and jasmonic-isoleucine, were found to play roles in somatic embryogenesis. This study provided comprehensive gene expression sets for mature seeds and immature embryos that were served as an important platform resource for further functional studies in plant embryogenesis. 展开更多
关键词 CALLUS immature embryo mature seed japonica rice RNA sequence HORMONE
下载PDF
Comparative proteomic analysis of mature and immature oocytes in domestic cats
10
作者 Bongkoch Turathum Kulnasan Saikhun +4 位作者 Sittiruk Roytrakul Chinnarat Changsangfa Supita Tanasawet Morakot Sroyraya Yindee Kitiyanant 《Asian pacific Journal of Reproduction》 2020年第1期22-30,共9页
Objective:To evaluate changes of feline(Felis catus)oocytes proteins during in vitro maturation by using the proteomic approach.Methods:Immature oocytes(germinal vesicle)isolated from female cats were cultured and col... Objective:To evaluate changes of feline(Felis catus)oocytes proteins during in vitro maturation by using the proteomic approach.Methods:Immature oocytes(germinal vesicle)isolated from female cats were cultured and collected at 0 h and 24 h.After collection,oocytes were investigated into immature(germinal vesicle)and mature(metaphaseⅡ)stages.The qualitative profiles of the proteins at the immature and mature stages were determined by one-dimensional electrophoresis and liquid chromatography-mass spectrometry.Results:Our data revealed that following 24 h in vitro maturation the maturation rate(metaphaseⅡstage)was 58.7%.Eighty-one of the 260 proteins analyzed were differentially expressed between the germinal vesicle stage and the metaphaseⅡ-arrest stage.Proteomic analysis of germinal vesicle and metaphaseⅡoocytes showed abundant expression of proteins involved in transportation(10%),indicating that this was a major characteristic of germinal vesicle oocytes.Similarly,analysis of the proteome of metaphaseⅡoocytes indicated that cell cycle proteins were overexpressed.Interestingly,proteins involved in DNA repair and apoptosis were only expressed in germinal vesicle oocytes and proteins involved in fertilization were only expressed in metaphaseⅡoocytes.Conclusions:The overexpression of certain proteins in germinal vesicle and metaphaseⅡis necessary for oocyte development and maturation.Our findings provide a valuable resource for further investigations into protein expression in oocytes at different developmental stages. 展开更多
关键词 Domestic CATS IMmature OOCYTES mature OOCYTES PROTEOMICS
下载PDF
Establishment of a Highly Efficient Regeneration System for the Mature Embryo Culture of Wheat 被引量:19
11
作者 YIN Gui-xiang WANG Yan-li +4 位作者 SHE Mao-yun DU Li-pu XU Hui-jun MA Jing-xiu YE Xing-guo 《Agricultural Sciences in China》 CAS CSCD 2011年第1期9-17,共9页
Establishment of a highly efficient regeneration system for the mature embryo of wheat will provide a convenient tool for wheat tissue culture and transformation, thereby facilitating the transformation of foreign gen... Establishment of a highly efficient regeneration system for the mature embryo of wheat will provide a convenient tool for wheat tissue culture and transformation, thereby facilitating the transformation of foreign genes into wheat. By using the mature embryos derived from 20 different wheat lines including Shi 4185, Yumai 66, Lunxuan 987, CB037, Yangmai 6, Xinchun 9, Bobwhite, Han 6172, Zheng 9023, Jimai 20, Ningchun 4, and Jing 411, the effects of some factors including inoculation methods, initiating culture media, organic additives, antioxidants, and auxins on the regeneration from the explants were evaluated. The results indicated that the scraping embryo culture was better than the whole embryo culture, the Aa medium was better than the SD2 medium and dicamba was better than 2,4-D in increasing the regeneration frequency. An Adi medium was established in this study by adding silver nitrate, cysteine, ascorbic acid, dicamba, glutamine into the Aa medium at the concentration of 4,40, 100, 2, and 5 mg L^-1, respectively. By using the Adi medium and the scraping technique, the regeneration frequencies of the mature embryos of CB037, Lunxuan 987, Hart 6172, Yangmai 6, Bobwhite, Zheng 9023, Shi 4 185, and Jimai 20 became 85.6, 60,1, 46.0, 42.1,42.0, 34.0, 33.0, and 32.0%, respectively, which were about 5-8 times higher than that obtained from the conventional culture mediums and techniques. This novel regeneration system could be helpful in wheat transformation. 展开更多
关键词 WHEAT mature embryo culture scraping treatment Adi medium highly efficient regeneration
下载PDF
Organic matter and concentrated nitrogen removal by shortcut nitrification and denitrification from mature municipal landfill leachate 被引量:16
12
作者 ZHANG Shu-jun PENG Yong-zhen WANG Shu-ying ZHENG Shu-wen GUO Jin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第6期647-651,共5页
An UASB+Anoxic/Oxic (A/O) system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and high ammonia concentration. To make the best use of the biodegradable COD in the leaehate, t... An UASB+Anoxic/Oxic (A/O) system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and high ammonia concentration. To make the best use of the biodegradable COD in the leaehate, the denitrifieation of NOx^--N in the reeireulation effluent from the elarifier was carried out in the UASB. The results showed that most biodegradable organic matters were removed by the denitrifieation in the UASB. The NH4^+-N loading rate (ALR) of A/O reactor and operational temperature was 0.28- 0.60 kg NH4^+-N/(m^3-d) and 17-29℃ during experimental period, respectively. The short-cut nitrification with nitrite accumulation efficiency of 90%-99% was stabilized during the whole experiment. The NH4^+-N removal efficiency varied between 90% and 100%. When ALR was less than 0.45 kg NH4^+-N/(m^3.d), the NH4^+-N removal efficiency was more than 98%. With the influent NH4^+-N of 1200-1800 mg/L, the effluent NH4^+-N was less than 15 mg/L. The shortcut nitrification and denitrifieation can save 40% carbon source, with a highly efficient denitrifieation taking place in the UASB. When the ratio of the feed COD to feed NH4^+-N was only 2-3, the total inorganic nitrogen (TIN) removal efficiency attained 67%-80%. Besides, the sludge samples from A/O reactor were analyzed using FISH. The FISH analysis revealed that ammonia oxidation bacteria (AOB) accounted for 4% of the total eubaeterial population, whereas nitrite oxidation bacteria (NOB) accounted only for 0.2% of the total eubaeterial population. 展开更多
关键词 mature landfill leachate UASB+A/O shortcut nitrification carbon source
下载PDF
Study on Plant Regeneration of Wheat Mature Embryos Under Endosperm-Supported Culture 被引量:11
13
作者 CHEN Jun-ying YUE Run-qing XU Hai-xian CHEN Xin-jian 《Agricultural Sciences in China》 CAS CSCD 2006年第8期572-578,共7页
To reveal the suitability of using mature embryos as an explant source in wheat tissue culture, mature embryos from eight common wheat cultivars (Triticum aestivum L. cv.) were cultured with or without endosperm to ... To reveal the suitability of using mature embryos as an explant source in wheat tissue culture, mature embryos from eight common wheat cultivars (Triticum aestivum L. cv.) were cultured with or without endosperm to test their efficiency of callus induction and plant regeneration. When embryos were cultured together with endosperm (endosperm-supported culture, ES), the percentage of callus induction was significantly lower than that when embryos were cultured in the absence of endosperm (non-endosperm-supported culture, NES). This pattern was evident in most genotypes, regardless of whether 2 or 8 mg L^-1 2,4-D was added in the NES culture. However, in ES culture, more induced calli were differentiated into distinct green spots and they further developed into plantlets. Thus, more plants were regenerated in ES culture than in the NES treatment. Most of the eight tested genotypes showed a significant difference in callus induction rate and plantlet regeneration in both ES and NES cultures. In addition, the enzymatic activity of oxalate oxidase in the callus of ES culture condition was obviously higher than that in the callus of NES culture condition, suggesting that the activity of oxalate oxidase may be a parameter for selection of calli with potential for plantlet regeneration. These results indicate that wheat mature embryos are valuable explants for highly efficient callus induction and plant regeneration, if proper treatment and medium are used. 展开更多
关键词 mature wheat embryo tissue culture endosperm-supported plant regeneration oxalate oxidase activity
下载PDF
Dicamba and Sugar Effects on Callus Induction and Plant Regeneration from Mature Embryo Culture of Wheat 被引量:12
14
作者 REN Jiang-ping,WANG Xin-guo and YIN Jun National Engineering Research Center for Wheat/Henan Agricultural University,Zhengzhou 450002,P.R.China 《Agricultural Sciences in China》 CSCD 2010年第1期31-37,共7页
To establish a highly efficient plant regeneration system for wheat genetic transformation, the effects of three different concentrations of dicamba and two different sugar types on callus induction and plant regenera... To establish a highly efficient plant regeneration system for wheat genetic transformation, the effects of three different concentrations of dicamba and two different sugar types on callus induction and plant regeneration from mature embryo cultures were evaluated. Callus induction and plant regeneration were obtained from mature embryos of two commercial cultivars Zhoumai 18 and Yumai 34 (Triticum aestivum L.) cultured on L3 basal medium. The results showed that the efficiency of mature embryo culture was significantly influenced by the genotypes, sugar types and dicamba concentrations. 4 mg L^-1 dicamba proved the best effective for inducing embryogenic callus and also gave the highest proportion of plants regenerated across the two cultivars. Substitution of maltose by sucrose significantly improved the plant regeneration efficiency in both cultivars. There was a significant interaction between genotype-by-sugar types, and sugar types-bydicamba concentrations. Overall, Zhoumai 18 gave the highest frequency of plant regeneration (82.65%) when dicamba concentration was 4.0 mg L^-1 and with sucrose in initial callus induction. These results will facilitate genetic transformation work with elite wheat. 展开更多
关键词 WHEAT mature embryo tissue culture plant regeneration
下载PDF
Species diversity,population structure and regeneration of woody species in fallows and mature stands of tropical woodlands of southeast Angola 被引量:5
15
作者 Francisco M.P.Goncalves Rasmus Revermann +2 位作者 Manuel J.Cachissapa Amandio L.Gomes Marcos P.M.Aidar 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第6期1569-1579,共11页
This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population str... This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population structure of the most harvested woody species by calculating size class distribution and evaluated their regeneration potential based on the density of saplings. The vegetation was surveyed in 20 plots of 20 × 50 m(1000 m2). In each plot, we measured the diameter at breast height(DBH) of all woody species with DBH ≥ 5 cm. The saplings were counted, identified and recorded; 718 individuals, corresponding to 34 species in 32 genera and 15 families were recorded. The size class distribution of target woody species showed three different patterns in fallows and mature woodlands. In general,most of the smaller diameter classes had more individuals than the larger ones did, showing that the regeneration may take place. However, in some diameter classes, the absence of larger stems indicated selective logging of larger trees. Few saplings were recorded in the fallows or mature woodlands; fire frequency and intensity is probably the main obstacle for seed germination and seedling survival rates in the studied area. 展开更多
关键词 Baikiaea woodlands Fallows mature woodlands REGENERATION Woody species
下载PDF
The Comparison in Tissue Culture Ability of Mature Embryo in Different Cultivars of Rice 被引量:7
16
作者 YAN Li-na LI Xia WU Dan 《Agricultural Sciences in China》 CSCD 2010年第6期840-846,共7页
In order to study the regeneration technology of mature embryos in different rice varieties,nine japonica,nine indica and eleven hybrid rice varieties of two line or three line or superiority combinations were selecte... In order to study the regeneration technology of mature embryos in different rice varieties,nine japonica,nine indica and eleven hybrid rice varieties of two line or three line or superiority combinations were selected as explants to study the callus induction,differentiation and regeneration rates on different media.The higher callus induction (61.7-89.2%) was observed in japonica rice,when cytokinin was added at lower concentration (0.3 mg L-1 6-BA) in M8 basal medium,supplemented with 30 g L-1 sucrose,8 g L-1 agar and 2 mg L-1 2,4-D.Further,the addition of two cytokinins (2 mg L-1 6-BA,0.5 mg L-1 KT) and 1 mg L-1 NAA in the M8 basal supplemented medium resulted in 9.1-100% of the callus induction in indica rice.The percent callus induction in hybrid rice varieties was 40-86.3% when addition of 1 mg L-1 6-BA and 1 mg L-1 KT was added,and the cytokinins was required by the japonica and indica rice varieties in the M8 basal supplemented medium.It was observed that when the 0.5 mg L-1 2,4-D and 1 mg L-1 6-BA were added in japonica rice,and 0.2 mg L-1 2,4-D and 0.5 mg L-1 6-BA were added in indica and hybrid rice in the MS different media,the regeneration rates were 9.2-59.5%,3.6-87.5% and 17.2-43.2% for japonica,indica and hybrid rice,respectively.Thus,the regeneration technology with higher output is established in the mature embryos of similar rice varieties. 展开更多
关键词 JAPONICA INDICA hybrid rice mature embryos HORMONE tissue culture ability
下载PDF
Establishment and Optimization of the Regeneration System of Mature Embryos of Maize (Zea mays L.) 被引量:4
17
作者 ZHAO Cheng-hao ZHANG Li-jun GE Chao HU Kai 《Agricultural Sciences in China》 CAS CSCD 2008年第9期1046-1051,共6页
A reliable system was developed for regeneration from mature embryos derived from callus of four maize inbred lines (Liao 7980, Dan 9818, Dan 340, and Dan 5026). The protocol was mainly based on a series of experime... A reliable system was developed for regeneration from mature embryos derived from callus of four maize inbred lines (Liao 7980, Dan 9818, Dan 340, and Dan 5026). The protocol was mainly based on a series of experiments involving the composition of culture medium. We found that 9 pM 2,4-dichlorophenoxyacetic acid in MS medium was optimum for the induction of callus. The induction frequency of primary calli was over 85% for four inbred lines tested. The addition of L- proline (12 mM) in subculture medium significantly promoted the formation of embryogenic callus but it did not significantly enhance growth rate of callus. Efficient shoot regeneration was obtained on regeneration medium containing 2.22 μM 6- benzylaminopurine in combinations with 4.64 μM Kinetin. Regenerated shoots were rooted on half-strength MS medium containing 2.85 μM indole-3-butyric acid. This plant regeneration system provides a foundation for genetic transformation of maize. 展开更多
关键词 maize (Zea mays L.) mature embryo callus induction embryogenic callus plant regeneration
下载PDF
Varietal Difference in Leaf Nitrogen Content and Leaf Area and Their Effects to Ripening Rate During Mature Period of japonica Rice 被引量:4
18
作者 LiRong-tian KojimaNobuyoshi 《Journal of Northeast Agricultural University(English Edition)》 CAS 1999年第2期81-88,共8页
Employing the pot experiment of the complete random block design with 6 replications,four varieties of japonica rice (Fujisaka 5,Honenwase,Akitakomachi and Taichung 65) were used to study the varietal differences in l... Employing the pot experiment of the complete random block design with 6 replications,four varieties of japonica rice (Fujisaka 5,Honenwase,Akitakomachi and Taichung 65) were used to study the varietal differences in leaf nitrogen content(LNC) and leaf area during mature period,their relation and effects to the ripening rate.The results showed that(1) thee were varietal differences in LNC at the heading stage and the LNC decrease rate during the matue period,the high LNC at the heading stage was related to the rapid LNC decrease.(2) There were two phases of the leaf area changing process during the mature period,first was the stable,and second was the decreased phase.There was varietal difference in the critical time of phase 1 and phase 2.The hign leaf area in the phase 1 was in relation to the rapid leaf area decrease in the phase 2.It was not found that there was relation between the leaf quality and quantity.(3)It wa unfavorable to the ripening rate for the high leaf area at the heading stage and the rapid decrease of the leaf area during the mature period.(4)It was put forward that the super high yield rice variety should possess the not very high leaf area and high LNC at the heading stage,slow senescence in the leaf area during the mature period. 展开更多
关键词 japonica rice leaf area leaf nitrogen content(LNC) mature period VARIETY
下载PDF
Application of cDNA array for studying the gene expression profile of mature appressoria of Magnaporthe grisea 被引量:3
19
作者 JIN Qing-chao DONG Hai-tao +8 位作者 PENG You-liang CHEN Bao-shan SHAO Jing DENG Ye DAI Cheng-en FANG Yong-qi LOU Yi-chun LI You-zhi LI De-bao 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2007年第2期88-97,共10页
Appressorium is an infection structure of the phytopathogenic fungus Magnaporthe grisea. Analysis of gene expression profiles ofappressorium development provides insight into the molecular basis of pathogenicity and c... Appressorium is an infection structure of the phytopathogenic fungus Magnaporthe grisea. Analysis of gene expression profiles ofappressorium development provides insight into the molecular basis of pathogenicity and control of this fungal plant disease. A cDNA array representing 2927 unique genes based on a large EST (expressed sequence tag) database ofM. grisea strain Y34 was constructed and used to profile the gene expression patterns at mycelium and appressorium maturation stages. Compared with mycelia, 55 up-regulated and 22 down-regulated genes were identified in mature appressoria. Among 77 genes, 16 genes showed no similarity to the genome sequences of M. grisea. A novel homologue of peptidyl-prolyl cis-trans isomerase was found to be expressed at low-level in mature appressoria of M. grisea. The results indicated that the genes such as pyruvate carboxylase, phospholipid metabolism-related protein and glyceraldehyde 3-phosphate dehydrogenase involved in gluconeogenesis, lipid metabolism and glycolysis, showed differential expression in mature appressoria. Furthermore, genes such as PTHll, beta subunit of G protein and SGTI involved in cell signalling, were expressed differentially in mature appressoria. Northern blot analysis was used to confirm the cDNA array results. 展开更多
关键词 Magnaporthe grisea mature appressoria cDNA array Gene expression profile
下载PDF
Evolution and organic geochemical significance of bicyclic sesquiterpanes in pyrolysis simulation experiments on immature organic-rich mudstone 被引量:3
20
作者 Gang Yan Yao-Hui Xu +2 位作者 Yan Liu Peng-Hai Tang Wei-Bin Liu 《Petroleum Science》 SCIE CAS CSCD 2019年第3期502-512,共11页
Sesquiterpanes are ubiquitous components of crude oils and ancient sediments.Liquid saturated hydrocarbons from simulated pyrolysis experiments on immature organic-rich mudstone collected from the Lower Cretaceous Hes... Sesquiterpanes are ubiquitous components of crude oils and ancient sediments.Liquid saturated hydrocarbons from simulated pyrolysis experiments on immature organic-rich mudstone collected from the Lower Cretaceous Hesigewula Sag were analyzed by gas chromatography-mass spectrometry(GC-MS).C14 bicyclic sesquiterpanes,namely,8β(H)-drimane,8β(H)-homodrimane,and 8 a(H)-homodrimane were detected and identified on basis of their diagnostic fragment ions(m/z123,179,193,and 207),and previously published mass spectra data,and these bicyclic sesquiterpanes presented relatively regular characteristics in their thermal evolution.The ratios 8β(H)-drimane/8β(H)-homodrimane,8β(H)-homodrimane/8 a(H)-homodrimane,and 8β(H)-drimane/8 a(H)-homodrimane all show a clear upward trend with increasing temperature below the temperature turning point.Thus,all these ratios can be used as evolution indexes of source rocks in the immature-lowmaturity stage.However,the last two ratios may be more suitable than the first ratio as valid parameters for measuring the extent of thermal evolution of organic matter in the immature-low-maturity stage because their change amplitude with increasing temperature is more obvious. 展开更多
关键词 Immature-low-maturity stage Simulated PYROLYSIS experiment BICYCLIC sesquiterpanes Thermal EVOLUTION MATURITY indicators
下载PDF
上一页 1 2 48 下一页 到第
使用帮助 返回顶部