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1.
根据定位观测数据,对海南文昌滨海台地3种典型森林(椰子林、相思林和木麻黄林)土壤微生物的数量特征及其与土壤因子的相互关系进行研究。结果表明,滨海台地3种森林类型中,微生物总量表现为椰子林相思林木麻黄林;细菌数量以椰子林土壤最高(3 144.67×10~4 CFU·g~(-1)),分别为相思林、木麻黄林的1.99倍和2.56倍;真菌数量以相思林最高(46.12×10~4 CFU·g~(-1)),分别为椰子林、木麻黄林的2.61和1.37倍;放线菌数量以椰子林最高(413.84×10~4 CFU·g~(-1)),分别为相思林、木麻黄林的3.32和1.42倍。不同森林类型土壤微生物三大类群数量,以细菌所占比例最大,放线菌次之,真菌最小。除椰子林真菌数量外,3种森林类型土壤微生物总数、细菌、真菌及放线菌数量均随土层深度的增加而减少,与土层深度呈线性负相关。土壤微生物数量与土壤养分含量之间存在着不同程度的相关关系,椰子林中,土壤全氮和有机碳是影响微生物数量的主要土壤因子;相思林中,全氮和pH值是影响微生物数量的主要因子;木麻黄林中,全氮和全磷是影响微生物数量的主要因子。 相似文献
2.
Rong Sheng Min Huang Heai Xiao Tida Ge Jinshui Wu Chengli Tong Zhoujin Tan Daping Xie 《Frontiers of Agriculture in China》2010,4(4):430-437
To understand the role of microbial processes in phosphorus (P) immobilization in a weathered subtropical soil, the effects
of application of a phosphatesolubilization microorganism strain (Pseudomonas sp. 2VCP1) on P availability in soil, dynamics in microbial biomass P (Bp), microbial biomass C (Bc) and Olsen-P were investigated during a 60-d laboratory incubation. The included treatments were P. sp. inoculums at ×106 cfu·g−1 soil (CKM); glucose at 5 g·kg−1 soil (G); G with P. sp. inoculum (GM); rice straw at 5 or 10 g·kg−1 soil (5S or 10S); 5S and 10S with P. sp. inoculum (5SM and 10SM). The results indicated that the amount of soil Bc increased about 3.2, 1.7, and 2.6 times for G, 5S and 10S compared to the control (no organic amendment and P. sp.; CK), respectively. The amount of soil Bp for G and 10S almost doubled during the first 7 d, then remained relatively steady. The amount of Olsen-P in G, 5S and 10S
showed a significant decrease (0–5.4 mg P·kg−1 soil) during the 60-d incubation compared to CK. However, changes in soil Bp between the treatments inoculated with P. sp. (CKM, G, 5SM, 10SM) and the uninoculated controls (CK, G, 5S, 10S) were not significant during the 60-d incubation period,
whereas a small increase in Bp of the GM treatment was seen up to day 11. The amount of soil Bc in CKM, GM, 5SM and 10SM had increased but not greater than 20% compared to their corresponding uninoculated control. The
amount of Olsen-P increased but not greater than 0.88 mg P·kg−1 soil. The result illustrated that there were a few effects on soil P immobilization following inoculation with P. sp. in the soil, whereas organic amendments can significantly motivate the soil native microorganisms to immobilize phosphorus. 相似文献
3.
Wenchao Zhen Shutong Wang Chengyin Zhang Zhiying Ma 《Frontiers of Agriculture in China》2009,3(1):7-12
A field experiment was conducted during the 2006–2007 wheat growing season at Baoding, Hebei Province, China, aiming at exploring
the influence of different amendment rates of maize straw on winter wheat soil-borne diseases induced by Rhizoctonia cereali, Gaeumannomyces graminis and Bipolaris sorokiniana in field conditions. Wheat root vitality, ion infiltration, SOD activity, MDA content and microbial population of the tillage
layer were measured. The results showed that the occurrence of three soil-borne diseases tested was significantly different
under different amendment rates. During the greening stage and jointing stage, the disease indexes of three soil-borne diseases
were reduced significantly by treatments at the maize straw amendment rates of 7500 kg · hm−2 and 3750 kg · hm−2. However, disease indexes of wheat common rot and sharp eyespot increased dramatically when the amendment rate increased
to 15000 kg · hm−2. At the amendment rate of 15000 kg · hm−2, wheat root vigor and SOD activity decreased, and ion infiltration and cell membrane-lipid peroxidation level increased,
respectively. In the meantime, higher amounts of bacteria and actinomycetes were recorded in the 7500 kg · hm−2 amendment rate treatment, while a higher amount of fungi was recorded in the 15000 kg · hm−2 amendment rate treatment. 相似文献
4.
Ran Guo Chhorn Lim Hui Xia Mediha Yildirim Aksor Menghe Li 《Frontiers of Agriculture in China》2010,4(4):507-512
Six purified vitamin-free casein-based diets were formulated to contain six levels vitamin A at 0, 500, 1000, 2000, 4000,
and 8000 IU·kg−1, respectively. Tilapias (initial mean weight: 7.73±0.03 g) were fed the diets in quadruplicate aquaria to apparent satiation
twice daily for 10 weeks. No differences in mortality, weight gain, or feed efficiency ratio (FER) were observed among the
groups. Liver vitamin A levels reflected dietary vitamin A levels. Immune parameters, such as hemoglobin levels, total cell
count, red blood cell count, total serum protein, and serum lysozyme activity, did not vary with the dietary vitamin A levels.
White blood cell counts of fish in 2000 IU·kg−1 diet groups were significantly higher than that in other diets groups. Serum complement activities of fish in 2000 and 4000
IU·kg−1 vitamin A diet groups were also higher than those in other diet groups. After the 14-d challenge test, the mortality and
antibody titer were similar among the treatments. The results indicated that dietary vitamin A inclusions did not affect the
immune response of Oreochromis niloticus. 相似文献
5.
The pear (Pyrus spp.) is one of the most important temperate fruit crops. A complete protocol for adventitious shoot regeneration was developed
from the leaves of four pear varieties grown in vitro: Abbe Fetel, Yali, Packham’s Triumph and Aikansui, and the Chinese rootstock variety Duli. Shoot explants were collected
from the field and cultured in vitro in Murashige and Skoog (MS) media supplemented with 1.0 mg·L−1 6-benzylaminopurine (BA) and 0.1 mg·L−1 indole-3-butyric acid (IBA). After four weeks, leaf explants of all 5 varieties grown in vitro were excised and cultured in MS media supplemented with 0.0 mg·L−1, 0.2mg·L−1, 0.5 mg·L−1, 1.0 mg·L−1 and 2.0 mg·L−1 naphthaleneacetic acid (NAA) and 5.0 mg·L−1 BA or with 1.0 mg·L−1, 2.0 mg·L−1 and 4.0 mg·L−1 thidiazuron (TDZ). The cultures were maintained in darkness for 21 days for shoot induction in the shoot induction medium
(IM), then transferred to the shoot expression medium (EM) in 1.0 mg·L−1 TDZ without any auxins and kept in a growth room at (25±2)°C under a 16/8 h light/dark photoperiod regime for 8 weeks. Finally,
the shoots were transferred to the MS shoot elongation medium (SEM) supplemented with 0.2 mg·L−1 BA, 0.1 mg·L−1 IBA and 0.2 mg·L−1 gibberellic acid (GA3). A combination of TDZ and NAA had a significant effect on the number of shoot regenerations in all 5 tested varieties. The
maximum mean number of shoots and maximum number of shoots per leaf obtained from Yali variety were 11.8 (P⩽0.001) and 22, followed by Aikansui with 6.6 (P⩽0.001) and 4.6, and Duli with 8 (P⩽0.001) and 12, all arising from the combination of 0.2 mg·L−1 NAA with 1.0 mg·L−1 TDZ. For Packham’s Triumph and Abbe Fetel, the maximum mean number of shoots and maximum number of shoots per leaf were 5.6
(P⩽0.001), 4.8 and 8 (P⩽0.001), and 11, respectively, from the combination of NAA (1.0 mg·L−1) and TDZ (2.0 mg·L−1). Abbe Fetel was the only variety which produced significantly higher adventitious shoots from the two different combinations
of 1.0 mg·L−1 NAA and 5.0 mg·L−1 BA (P⩽0.05), and 2.0 mg·L−1 NAA and 5.0 mg·L−1 BA (P⩽0.01). Some of the most prominent problems associated with shoot proliferation and regeneration were also observed and discussed
in this paper. 相似文献
6.
通过双抗药性标记法(抗利福平和硫酸链霉素)和扫描电子显微镜观察法研究了枯草芽孢杆菌RSS-1R菌株在油菜植株和根际土壤的定殖。结果表明,喷雾处理后2~6 d内,油菜植株上RSS-1R菌株的平均菌量从3.67×105 cfu·g-1鲜组织下降到1.00×103 cfu·g-1鲜组织;到处理后10 d,油菜植株上即检测不到RSS-1R菌株;喷雾处理30 d内,油菜根际土壤中菌株RSS-1R种群数量呈现出先上升后下降的趋势。灌根处理后,菌株RSS-1R可在油菜根际土壤中稳定定殖30 d以上,且其种群数量无显著变化。同时研究了RSS-1R菌株对油菜周围微生物种群数量的影响。结果表明,喷雾处理2~10 d后,油菜植株上的细菌种群数量由6.30×106 cfu·g-1湿土下降到3.00×105 cfu·g-1湿土,处理后10 d,油菜植株上的细菌种群数量恢复到对照水平。喷雾处理10 d内油菜根际土壤中的细菌种群数量与对照差异不显著,但是处理后20 d,油菜根际土壤中的细菌种群菌量显著增加。灌根处理后,油菜根际土壤中的细菌种群数量呈现出先增加后下降的趋势,处理后30 d,油菜根际土壤中的细菌种群数量恢复到对照水平。无论是喷雾还是灌根处理均不影响油菜植株或根际土壤中的真菌和放线菌的种群数量。 相似文献
7.
开展对蝉花不同食用方式下其子实体、菌核、浸提液和浸提后蝉花,进行麦角甾醇、虫草素、腺苷和多糖的定量研究,以期得出有实用价值的差别性数据,为对蝉花进一步的综合利用提供理论数据。不同食用方式分为直接食用蝉花粉末、水煮后制剂和水煮后蝉花整食。根据市场上将蝉花质量高低按子实体大小划分,分别开发食用蝉花子实体、蝉花菌核、蝉花浸提液和浸提后蝉花。研究结果表明:(1)麦角甾醇。子实体中为0.34±0.05 mg·g~(-1),浸提蝉花中为0.31±0.03 mg·g~(-1),菌核中为0.07±0.01 mg·g~(-1),浸提液中未检出。(2)虫草素。子实体中为0.54±0.04mg·g~(-1),浸提蝉花中为0.28±0.02 mg·g~(-1),浸提液中为0.37±0.03 mg·g~(-1),菌核中为0.14±0.02 mg·g~(-1)。(3)腺苷。子实体中为0.61±0.04 mg·g~(-1),浸提蝉花中为0.35±0.05 mg·g~(-1),菌核中为0.30±0.06 mg·g~(-1),浸提液中为0.45±0.04 mg·g~(-1)。(4)多糖。菌核中为(14.84±1.79)%,浸提蝉花中为(13.34±0.95)%,子实体中为(13.17±1.02)%,浸提液中为(9.61±0.71)%。结果显示,蝉花子实体、菌核与浸提前后蝉花活性成分存在差异。 相似文献
8.
Chunlong Liu Zhongqiu Li Fugang Peng Yanming Ren Zhuolong Wang 《Frontiers of Agriculture in China》2009,3(1):89-94
In a completely randomized block design experiment, 16 ruminally cannulated male sheep with body weights of (40 ± 2.1) kg
were fed twice daily (8:00 and 16:00) with concentrate and forage (50:50 on dry matter (DM) basis). Dietary treatments were
supplemented with intraruminal doses of powdered Yucca schidigera extract (YSE) at the levels of 0 (control), 100, 200 and 300 mg · kg−1. On days of 15, 16 and 17 after feeding, ruminal content was sampled at 0, 2, 4, 6 and 8 h after dosing (8:00), and blood
samples were collected at the end of experiment (the days 18 and 19 after feeding). Results showed that the treatment groups’
acidity was not affected (P = 0.13) by YSE. Comparing to the control, the ruminal propionate concentration was increased by YSE addition in a dose-dependent
manner by up to 29.8% (P < 0.05), and the acetic concentration was decreased by up to 17.5% (P < 0.05). The ruminal ammonia concentration 2 hours after feeding was higher (P < 0.05) in sheep fed without YSE (increased by 17.57 mg· 100 mL−1) than those fed with YSE at 200 mg · kg−1 (6.77 mg · 100 mL−1 increase in NH3) and at 300 mg · kg−1 (6.50 mg· 100 mL−1 increase in NH3). Protozoal populations in the rumen were lower (P < 0.05) with the YSE feeding dose at 300 mg · kg−1 than the control. The serum chemistries were not different among treatments (P > 0.05) and were within the normal physiological ranges for sheep 19 days after feeding. The study indicated that 200 mg·
kg−1 and 300 mg· kg−1 YSE groups had particular suppressing effects on ruminal ammonia concentration, ammonia-N concentrations and protozoal populations.
The effect of YSE on ruminal fermentation could be attributed to the selective inhibitory effect on rumen microbial species.
High level (300 mg · kg−1) YSE as feed additives resulted no negative impact on sheep in our tests. 相似文献
9.
A greenhouse experiment was conducted to study the accumulation of selenium by some vegetable crops commonly grown in the
Indian Punjab. Eleven vegetable crops were raised in an alkaline clay loam soil treated with different levels of selenate-Se,
i.e., 0, 1.25, 2.5 and 5.0 mg·kg−1 soil. Dry matter yield of both edible and inedible portions of different vegetable crops decreased with increasing Se level
in soil except potato (Solanum tuberosum), radish (Raphanus sativus) and cauliflower (Brassica oleracea var. botrytis) which recorded 10%–21% increase in inedible dry matter at 1.25 mg·kg−1 Se soil. Application of 5 mg·kg−1 selenate-Se soil resulted in complete mortality in the case of radish, turnip (Brassica rapa) and brinjal (Solanum melongena). Some vegetable crops including tomato (Lycopersicum esculentum), cauliflower and pea (Pisum sativum), though, survived the toxic effect at the highest concentration of Se yet did not bear any fruit. Potato and spinach (Spinacea oleracea) proved to be highly tolerant crops. Selenium concentration in the edible as well as inedible portions of all the vegetables
increased with an increase in the level of applied Se. Selenium accumulation in the edible portion of vegetable crops in the
no-Se control ranged from 2.2 to 4.9 mg·kg−1 Se dry weight. At 1.25 mg·kg−1 Se soil, the edible portion of radish accumulated the greatest concentration of Se (38 mg·kg−1 Se dry weight) with that of onion (Allium cepa) bulb the lowest (9 mg·kg−1 Se dry weight). Inedible portions of vegetables accumulated Se 2–5 times more than that absorbed by edible portions. Total
Se uptake by edible portions of different vegetables was the greatest at 1.25 mg·kg−1 Se soil, ranging from 7 to 485 μg·pot−1. The results suggest that vegetable crops vary in their sensitivity to the presence of selenate-Se in soil. Vegetative portions
were several times richer in Se than other parts of vegetable crops. 相似文献
10.
Huitao Li Kangsen Mai Qinghui Ai Chunxiao Zhang Lu Zhang 《Frontiers of Agriculture in China》2009,3(1):78-83
Cadmium (Cd) is a toxic environmental pollutant with a long biological half-life and can produce both hepatic and renal injuries
in mammals and fish. Squid viscera meal (SVM), an effective attractant for aquatic animals, is widely used as an ingredient
in aquafeeds. However, SVM is rich in Cd and its complexes. A study was conducted to evaluate the effects of dietary SVM on
the growth and Cd deposition in the tissues of large yellow croaker, Pseudosciaena crocea R. Three practical diets were formulated to contain a 0, 50 and 100 g · kg−1 SVM diet, correspondingly containing a 0.21, 7.26 and 12.08 mg Cd · kg−1 diet. Each diet was randomly assigned to triplicate groups of 100 juveniles of large yellow croaker (mean initial weight,
9.75 ± 0.35 g) in floating sea cages (1.0 m × 1.0 m × 1.5 m). Fish were fed twice daily (05:00 and 17:00) to satiation for
8 weeks. The results showed that there were no significant differences in fish survival among the three dietary treatments,
but significant higher specific growth rates (SGR) were observed in the fish fed diets with 50 or 100 g · kg−1 SVM diet compared to the control group (P < 0.05). The cadmium concentrations in fish tissues (muscle, liver, kidney and gill) were significantly influenced by the
dietary SVM. The cadmium concentrations in all tissues significantly increased with increasing dietary Cd levels (P < 0.05). In all the dietary treatments, the highest Cd level was always observed in the kidney, followed by the liver and
the gill. Fish fed diets with 50 and 100 g · kg−1 SVM had significantly higher Cd accumulations in the kidney (2.65, 4.44 mg · kg−1), liver (0.58, 0.93 mg · kg−1) and gill (0.35, 0.53 mg · kg−1) compared with the control group (0.42, 0.26 and 0.12 mg · kg−1, respectively). The Cd level in fish muscle, however, was undetectable in all treatments. Therefore, based on these results,
accumulation of Cd in edible tissue (muscle) of farmed large yellow croaker is not a food safety issue. However, long-term
feeding of diets with SVM may result in accumulation of Cd in the kidney, liver and gills of fish. 相似文献
11.
秸秆还田配施化肥对砂姜黑土固碳细菌的影响 总被引：1，自引：0，他引：1
农田生态系统是陆地生态系统中最活跃且固碳潜力最大的碳库之一,其中,细菌在农田生态系统生物固碳过程中发挥着重要作用。采用PCR-克隆测序技术、末端限制性酶切长度多态性分析技术(T-RFLP)及荧光定量PCR技术研究了不施肥(CK),施氮磷钾肥(CK-F),单独秸秆还田(W-NF)和施氮磷钾加秸秆还田(W-F)4种施肥管理对砂姜黑土固碳细菌群落结构、多样性及丰度的影响。结果表明,秸秆还田土壤的固碳细菌主要包括Nitrosomonas,Mesorhizobium和Bradyrhizobium等。在CK和W-NF处理中,土壤固碳细菌以严格自养菌为主,优势种群为亚硝化单胞菌属(Nitrosomonas),相对丰度分别为73.2%和72.4%。在CK-F和W-F处理中,土壤固碳细菌中严格自养菌相对丰度减小,而兼性自养菌相对丰度大幅增加。其中,CK-F的优势种群为亚硝化单胞菌属(Nitrosomonas)和中慢生根瘤菌属(Mesorhizobium),相对丰度分别为33.3%和17.6%。W-F的优势种群为亚硝化单胞菌属(Nitrosomonas)和慢生根瘤菌属(Bradyrhizobium),相对丰度分别为26.4%和24.5%。施用化肥及秸秆还田均显著提高了土壤固碳细菌群落的多样性,其中化肥的影响大于秸秆还田。主成分结果显示施肥对土壤固碳细菌群落结构的影响大于秸秆还田。4个处理土壤固碳功能基因(cbb L)丰度为1.32×107~3.29×107拷贝·g-1(干土),施肥及秸秆还田均能显著提高土壤细菌cbb L基因丰度,其中秸秆还田配施化肥的cbb L基因丰度最大。上述结果表明了施肥及秸秆还田对土壤固碳细菌群落结构,多样性及数量均有显著的影响。 相似文献
12.
Jiao Xu Wenchao Xu Lihui Zhang Chuan Li Jinlin Zhang 《Frontiers of Agriculture in China》2009,3(2):171-177
The herbicidal mechanism of the components extracted from Pythium aphanidermatum was examined in this study. Component I was isolated using the HPD500 macroporous adsorption resin and HPLC. Its impact on
seed germination and plant growth of weeds was determined and the contents of MDA, superoxide anion radical, and the activities
of hills and roots were examined. The root length of weed plants was inhibited under illumination while the stem height was
inhibited evidently under darkness. The relative electric conductivity of Digitaria sanguinalis and Amaranthus retroflexus under illumination was 94.55 μS·cm−1 and 58.75 μS·cm−1, respectively, whereas that under darkness was 85.25 μS·cm−1 and 36.25 μS·cm−1, respectively. The MDA contents of Digitaria sanguinalis and Chlorella pyrenoidosa were 0.08385 μmol·L−1 and 0.1742 μmol·L−1 under illumination, respectively, while those were 0.0129 μmol·L−1 and 0.01935 μmol·L−1 under darkness, respectively. Simultaneously, superoxide anion radical content was higher under illumination than under darkness.
These results showed the photosynthesis was affected by component I extracted from Pythium aphanidermatum. 相似文献
13.
广东罗非鱼养殖区水体及鱼体中多环芳烃的含量与健康风险 总被引：4，自引：2，他引：2
利用气相色谱质谱仪(GC-MS)对广东罗非鱼主要养殖区水体及罗非鱼肌肉中16种优控多环芳烃(PAHs)的含量进行检测,并用美国环保局(USEPA)推荐的健康风险评价模型对罗非鱼食用安全进行健康风险评价。结果表明:水体中16种多环芳烃总量为272.53 ng·L-1,范围为53.55~679.97 ng·L-1;罗非鱼肌肉PAHs残留含量范围为182.66~717.20 ng·g-1,平均含量为355.28 ng·g-1;多环芳烃的组成以低环为主,在水体及罗非鱼肌肉所占比例分别为69.64%~97.09%和59.70%~74.46%;罗非鱼经食用所含6种致癌PAHs造成个人年致癌风险值范围为2.87×10-6~1.56×10-5a-1,低于国际辐射防护委员会(ICRP)推荐的最大可接受风险水平(5.0×10-5a-1),但存在一定的致癌风险,8种非致癌PAHs有害污染物对人体的总非致癌风险为2.51×10-10~1.54×10-9a-1,低于国际标准值,健康风险较低。 相似文献
14.
Wenkui Liu Qixue Fan Bangke Zhu Haiming Du Xigang Feng 《Frontiers of Agriculture in China》2008,2(1):110-114
The effects of prey density (0.1, 0.3, 1, 3 and 10 prey·mL−1) on the growth and survival of hybrid snakehead (Channa argus × C. maculate) larvae were investigated. The larvae were divided into three groups with different body lengths of 0.68 cm, 1.50 cm and
3.20 cm, respectively. The growth of the hybrid snakehead larvae in all three groups increased with prey density increasing
from 0.1 to 1 prey·mL−1. The specific growth rate (SGR) was the highest when the prey density was 1 prey·mL−1. When prey density was higher than 1 prey·mL−1, SGR of larvae in Group I (the larvae of early development stage) decreased, while no significant change was observed in
those of Group II and Group III. The survival rates of hybrid snakehead larvae in all three groups were high (91.11%–100%)
and not significantly affected by the prey densities except in Group I with the highest prey density (10.0 prey·mL−1) which was significantly lower than the others. Body size was not sensitive to prey density. The optimum prey density was
confirmed at 1 prey·mL−1 in all the treatments.
__________
Translated from Journal of Huazhong Agricultural University, 2007, 26(3): 367–370 [译自: 华中农业大学学报] 相似文献
15.
Yan Bai Ge Ying Yongquan Lu Wei Tian Yanming Li 《Frontiers of Agriculture in China》2010,4(2):210-214
This study was focused on optimizing the conditions of soft-wood cutting for Atractylodes macrocephala Koidz., including the concentration and treatment time of IBA and IBA + NAA and the proportion of turf to perlite in substrates.
L9(34) orthogonal design with three factors and three levels were adopted, and the best combination was chosen after formula analysis,
variance analysis, and range analysis. The results showed that both the maximum survival rate and rooting rate were 93.33%.
Statistic analysis showed that treatment with IBA (200 mg·L−1) + NAA (100 mg·L−1) for 20 s, turf to perlite ratio of 1:3 would be the most favorable combination for soft-wood cutting of A. macrocephala. 相似文献
16.
To investigate the inductive effect of salicylic acid (SA) on the resistance of Pyrus bretschneider cv Yali to black spot disease (Alternaria kikuchiana Tanaka), the physiological and biochemical characteristics of detached pear leaves at the age of 5 to 10 days were measured
after application of SA. The results showed that exogenous SA significantly improved the resistance of Yali pear (Pyrus bretschneider cv Yali) leaves to black spot disease. For the SA treatment at 0.02 mmol·L−1 SA concentration, the disease index was the lowest, and the induced resistance reached up to 63.9%. Furthermore, SA induced
local and systemic resistance of Yali pear against the black spot disease. Expression of systemic resistance in leaves was
detectable 3 d after SA treatments and lasted for 10 d. POD, PPO, and PAL activities of Yali pear leaves increased by SA treatment.
It is suggested that exogenous SA solution as a chemical activator could induce the resistance of Yali pear to black spot
disease. 相似文献
17.
对安康市木瓜属3个种（光皮木瓜［C. (Thouin.) Koehne．］、皱皮木瓜［C． speciosa (Sweet.) Nakai．］、毛叶木瓜［C．Cathayensis (Hemsl.) Schneid．］）果实含水量、粗蛋白质、粗脂肪、可滴定酸、可溶性固形物、粗纤维等主要营养物质进行测定。结果表明：安康市木瓜属3个种果实含水,差异不显著,均超过71%,变异系数小;粗蛋白质差异极显著,皱皮木瓜最大（3.95 g·100 g-1）,光皮木瓜最小（2.05 g·100 g-1）;粗脂肪差异极显著,毛叶木瓜最大（0.67 g·100 g-1）,光皮木瓜最小（0.37 g·100 g-1）;可滴定酸差异不显著,但变异系数大,毛叶木瓜可滴定酸含量最大（2.82 g·100 g-1）,光皮木瓜最小（1.84 g·100 g-1）;可溶性固形物差异显著,光皮木瓜可溶性固形物最大（12.67 g·100 g-1）,毛叶木瓜最小（8.67 g·100 g-1）;粗纤维差异极显著,光皮木瓜最大（19.68 g·100 g-1）,毛叶木瓜最小（1.02 g·100 g-1）。对安康市木瓜属3个种果实主要营养成分测定分析,为木瓜属植物选育和产品加工提供依据,对木瓜属植物开发利用具有十分重要的意义。 相似文献
18.
Consumption and processing of allochthonous plant litter by fishes is more common in tropical than temperate streams and rivers.
Therefore, aquatic hyphomycetes in water (filtration), leaf litter (bubble chamber incubation), and fecal pellets (direct
observation and inoculation to sterile leaf litter) of three dominant fishes belonging to the family Cyprinidae (Aplocheilus lineatus, Puntius filamentosus, and Rasbora daniconius) in two locations of the River Kali of the Western Ghats, India, were evaluated during postmonsoon season. Spores of 14 and
9 species of aquatic hyphomycetes were recovered on filtering water samples of Kaiga stream and Kadra dam with equal number
of spores (32 spores · 100 mL−1) and high Shannon diversity in Kaiga stream. In a bubble chamber incubation of leaf litter, 16 and 9 species were recovered
from Kaiga stream and Kadra dam with high spore output (1122 versus 324 spores per mg dry mass) and high Shannon diversity
in Kaiga stream. Both direct and indirect methods of examination of fecal pellets of fishes revealed more species in Kaiga
stream than Kadra dam (4–7 versus 1–4 species). The spore release in leaf litter incubated with fecal pellets ranged from
2.3 to 98 spores·mg−1·d−1 with the highest Aplocheilus lineatus in Kaiga stream; while in Kadra dam, it was from 0.02 to 22.9 spores·mg−1·d−1 with the highest in Puntius filamentosus. The Shannon diversity of aquatic hyphomycetes was high in fecal pellets of Aplocheilus lineatus of Kaiga stream and Rasbora daniconius of Kadra dam. The top-ranked five species of aquatic hyphomycetes differed in water, leaf litter, and fish fecal pellets;
however, Triscelophorus konajensis was common for all. All five top-ranked species of aquatic hyphomycetes in feces produced multicelled spores; thus, they
were likely to have a better chance of viability through gut passage than single-celled spores. Preferential feeding, fungi
in gut and feces, and survival and dissemination of spores by invertebrates and fishes with reference to aquatic hyphomycetes
were discussed. 相似文献
19.
添加藻类和有机肥对罗非鱼养殖水体浮游植物群落结构的影响 总被引：1，自引：0，他引：1
为阐明施肥及添加外源藻类在水产养殖增产、增效及废物资源化利用方面的内在机理,以鸡粪和牛粪为试验有机肥,以小球藻和栅藻为外源添加藻类,设置空白组(Control)、加藻组(Algae)、鸡粪-藻组(Chicken-A)、牛粪-藻组(Cattle-A)、鸡粪-牛粪-藻组(C-C-A)5种处理方式,采用香农-威纳多样性指数和Pielou均匀度指数评价了施用有机肥和添加藻类对罗非鱼养殖水体中浮游植物群落结构的影响。结果表明,空白组、加藻组、鸡粪-藻组、牛粪-藻组、鸡粪-牛粪-藻组分别鉴定出19、26、34、27和31种藻类,种类数总体表现为:Chicken-AC-C-ACattle-AAlgaeControl;总丰度分别变化在1.52×10~7~6.99×10~7cells·L~(-1)、4.18×10~7~6.58×10~7cells·L~(-1)、1.24×10~7~9.58×10~7cells·L~(-1)、4.37×10~6~5.36×10~7cells·L~(-1)、1.06×10~7~8.63×10~7cells·L~(-1)之间,试验组和对照组的藻类总丰度都呈先降低后升高的变化趋势。对照组蓝藻比例先升高后降低,试验组蓝藻比例都不断降低;试验组蓝藻比例的降低幅度高于对照组,且鸡粪-藻组的降低幅度最大。对照组和试验组的绿藻比例都不断升高,但试验组的升高幅度高于对照组,且鸡粪-藻组的升高幅度最大。试验组的藻类多样性指数和均匀度指数都高于对照组,且多样性指数的变化顺序表现为:Chicken-AC-C-ACattleAAlgaeControl。在养殖水体中添加有机肥和藻类具有抑制蓝藻生长、促进绿藻生长、改善浮游植物群落结构的功效,且鸡粪优于牛粪或鸡粪-牛粪混合。 相似文献
20.
集约化养鸡场空气环境中生物气溶胶特点研究 总被引：3，自引：0，他引：3
为了给北京地区不同类型养鸡场空气环境中生物气溶胶的危害评价提供基础数据,对蛋鸡和肉鸡两种养殖方式下,鸡舍内外空气环境中生物气溶胶的浓度和粒径分布进行检测,并对大肠菌群和抗生素抗性菌进行了分析。结果表明,北京郊区(县)蛋鸡舍内,所调查的五种生物气溶胶(细菌、真菌、大肠菌群、四环素和红霉素抗性菌)浓度高于同地区肉鸡舍(P<0.05)。蛋鸡舍内空气中约50%的细菌气溶胶分别具有四环素和红霉素抗性;大肠菌群、四环素抗性大肠菌群和红霉素抗性大肠菌群的平均浓度分别为7.32×103、2.87×103CFU·m-3和3.31×103CFU·m-3。两种养殖方式下细菌和真菌气溶胶粒径分布规律有所差异,导致其在细颗粒物中所占比例不同。 相似文献