‘哈伯’南天竹组织培养和快速繁殖     

张俊林  樊靖  胡玉春  杨浩  胡绍庆  沈柏春 《农学学报》2021,11(10):63-68

为建立‘哈伯’南天竹组织培养和种苗繁育技术体系,以半木质化带芽茎段为外植体材料开展植株再生研究。通过观察对比试验法、L₉(3⁴)正交试验设计完全随机法、极差分析、显著性检验、LSD多重比较,探讨了‘哈伯’南天竹组培的最适培养基配方。试验结果表明：最佳诱导培养基为MS + 6-BA 2.0 mg/L + IBA 0.1 mg/L +蔗糖30 g/L,诱导萌动率71.77%,成活率85.51%;最佳增殖培养基为WPM +6-BA 1.5 mg/L + IBA 0.01 mg/L + 蔗糖30 g/L,增殖系数6.3;最佳生根培养基为1/2 MS+ IBA 0.5 mg/L + NAA 1.0 mg/L + 蔗糖20 g/L + AC 0.2 g/L,生根率97.63%;试管苗移入泥炭土:珍珠岩=3:2(V/V)混合基质中,移栽成活率96.67%。该试验建立了高效稳定的组培快繁技术体系,得到的组培苗后代能够稳定的保持母本优良性状,为工厂化育苗提供了技术支撑。  相似文献   

东北宿根花卉在花海建设中的应用——以莲花山花海项目为例     

张晓丽  陈亚林  程彬  杨帆  朱春英  于春波 《吉林林业科技》2021,50(5):30-33

本文以莲花山南北向花海的东北宿根花卉种植为例,介绍了东北宿根花卉在花海及园林绿化工程中的应用,并总结了在施工过程中遇到的问题,为今后花海的景观设计及施工提供思路和方向.  相似文献   

Mammary carcinoma arising in an adenoma in a ewe     

Shelley J. Newman  Stephen A. Smith  Kurt Zimmerman 《Journal of veterinary diagnostic investigation》2021,33(3):566

A large, firm, multi-cystic mammary gland mass grew slowly over 4 y in a 12-y-old, female Finn–Shetland cross sheep. A diagnosis of epithelial malignancy was suspected following fine-needle aspiration cytology at 30 mo after initial observation. The sheep was euthanized when the flock was downsized 18 mo later. A field postmortem examination revealed a large mammary mass, but an absence of metastases to internal organs. Imprint cytology of the mammary tissue supported a benign proliferative process. Histologically, mammary tissue was obliterated by cystic, tubular, and papillary adenomatous arrangements of mammary epithelium, with an anaplastic component, consistent with mammary carcinoma arising in an adenoma. IHC showed strong nuclear positivity to the antibody against progesterone receptor and minimal positivity to the antibody against estrogen receptor alpha expression. Intrinsic subtyping for basal or luminal epithelial origin was attempted through adaptation of companion animal IHC classification panels; high- and low-molecular-weight cytokeratins (CK5, CK8, CK18) failed to stain, but p63 expression for basal epithelium was positive.  相似文献   

Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau          下载免费PDF全文

J. Cao  Y. Gong  E. T. Yeh  N. M. Holden  J. F. Adamowski  R. C. Deo  M. Liu  J. Zhou  J. Zhang  W. Zhang  S. Zhang  D. Sheng  S. Yang  X. Xu  M. Li  Q. Feng 《Soil Use and Management》2017,33(4):663-671

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.  相似文献   

Utilizing a DUALEM‐421 and inversion modelling to map baseline soil salinity along toposequences in the Hunter Valley Wine district          下载免费PDF全文

U. Stockmann  J. Huang  B. Minasny  J. Triantafilis 《Soil Use and Management》2017,33(3):413-424

In the oldest commercial wine district of Australia, the Hunter Valley, there is the threat of soil salinization because marine sediments underlie the area. To understand the risk requires information about the spatial distribution of soil properties. Electromagnetic (EM) induction instruments have been used to identify and map the spatial variation of average soil salinity to a certain depth. However, soils vary with depth dependent on soil forming factors. We collected data from a single‐frequency and multiple‐coil DUALEM‐421 along a toposequence. We inverted this data using EM4Soil software and evaluated the resultant 2‐dimensional model of true electrical conductivity (σ – mS/m) with depth against electrical conductivity of saturated soil pastes (EC_p – dS/m). Using a fitted linear regression (LR) model calibration approach and by varying the forward model (cumulative function‐CF and full solution‐FS), inversion algorithm (S1 and S2), damping factor (λ) and number of arrays, we determined a suitable electromagnetic conductivity image (EMCI), which was optimal (R² = 0.82) when using the full solution, S2, λ = 3.6 and all six coil arrays. We conducted an uncertainty analysis of the LR model used to estimate the electrical conductivity of the saturated soil‐paste extract (EC_e – dS/m). Our interpretation based on estimates of EC_e suggests the approach can identify differences in salinity, how these vary with parent material and how topography influences salt distribution. The results provide information leading to insights into how soil forming factors and agricultural practices influence salinity down a toposequence and how this can guide soil management practices.  相似文献   

Comparing the behavioural thermoregulation response to heat stress by Atlantic salmon parr (Salmo salar) in two rivers     

Emily Corey  Tommi Linnansaari  Stephen J. Dugdale  Normand Bergeron  Jean-François Gendron  Michel Lapointe  Richard A. Cunjak 《Ecology of Freshwater Fish》2020,29(1):50-62

Climate change is expected to increase the frequency and magnitude of extreme thermal events in rivers. The Little Southwest Miramichi River (LSWM) and the Ouelle River (OR) are two Atlantic salmon (Salmo salar) rivers located in eastern Canada, where in recent years, water temperatures have exceeded known thermal limits (~23°C). Once temperature surpasses this threshold, juvenile salmon exploit thermal heterogeneity to behaviourally thermoregulate, forming aggregations in coolwater refuges. This study aimed to determine whether the behavioural thermoregulation response is universal across rivers, arising from common thermal cues. We detailed the temperature and discharge patterns of two geographically distinct rivers from 2010 to 2012 and compared these with aggregation onset temperature. PIT telemetry and snorkelling were used to confirm the presence of aggregations. Mean daily maximum temperature in 2010 was significantly greater in the OR versus the LSWM (p = 0.005), but not in other years (p = 0.090–0.353). Aggregations occurred on 14 and 9 occasions in the OR and LSWM respectively. Temperature at onset of aggregation was significantly greater in the OR (T_onset = 28.3°C) than in the LSWM (T_onset = 27.3°C; p = 0.049). Logistic regression models varied by river and were able to predict the probability of aggregation based on the preceding number of hours >23°C (R² = 0.61 & 0.65; P₅₀ = 27.4°C & 28.9°C; in the OR and LSWM respectively). These results imply the preceding local thermal regime may influence behaviour and indicate a degree of phenotypic plasticity, illustrating a need for localised management strategies.  相似文献   

The value of sea urchin,Lytechinus variegatus,egesta consumed by shrimp,Litopenaeus vannamei     

Karen E. Jensen  J. Christopher Taylor  Robert J. Barry  Louis R. D'Abramo  D. Allen Davis  Stephen A. Watts 《Journal of the World Aquaculture Society》2019,50(3):614-621

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.  相似文献   

Do cover crops change the lability of phosphorus in a clayey subtropical soil under different phosphate fertilizers?          下载免费PDF全文

A. P. B. Teles  M. Rodrigues  W. F. Bejarano Herrera  A. Soltangheisi  L. R. Sartor  P. J. A. Withers  P. S. Pavinato 《Soil Use and Management》2017,33(1):34-44

Plants have developed different mechanisms to absorb and solubilize phosphorus (P) in the soil, especially in environments with low P availability. This study evaluated the effects of different winter cover crops on soil P availability in a clayey subtropical (Hapludox) soil receiving soluble P fertilizer and a rock phosphate applied to the summer crop, under no‐tillage. The experiment was carried out over 3 yrs (2009–2011) with five different cover crop species: common vetch, fodder radish, ryegrass, black oat, white clover and fallow as control. The soil was sampled after the third year of cover crop cultivation and analysed for inorganic and organic P forms according to the well‐established Hedley fractionation procedure. Phosphate fertilizers promoted accumulation of both labile and nonlabile P pools in soil in the near surface layer, especially under rock phosphate. Fertilizer applications were not able to change P fractions in deeper layers, emphasizing that the Brazilian clayey soils are a sink of P from fertilizer and its mobility is almost nil. Although the cover crops recycled a great amount of P in tissue, in a short‐term evaluation (3 yrs) they only changed the content of moderately labile P in soil, indicating that long‐term studies are needed for more conclusive results.  相似文献   

Comparison of outcomes following treatment of septic calcaneal bursitis by needle or bursoscopic lavage: A retrospective study of 29 horses     

M. J. S. Duggan  T. S. Mair 《Equine Veterinary Education》2021,33(3):135-142

Sepsis of the calcaneal bursae (CB) presents significant treatment challenges with limited clinical data available in the literature. The objective of this retrospective cohort study was to assess the clinical outcomes associated with CB lavage using either a through-and-through needle or bursoscopic technique. Clinical records of 29 horses treated for septic calcaneal bursitis using either technique between 2005 and 2019 were reviewed. Fisher’s exact test was used to assess statistical significance between first surgical technique and success at first surgery (i.e. not requiring >1 lavage), survival to discharge and return to work (RTW). Bursoscopy was performed in 13/29 (44.8%) cases, and needle lavage in 16/29 (55.2%). In the needle group, 12 (75%) horses were discharged following the first surgery. Four had repeat interventions; two (12.5%) had needle lavage and two (12.5%) had bursoscopy. Of the two horses to have repeat needle lavage, one was subjected to euthanasia and one discharged, and of the two that underwent bursoscopy, one was discharged and one received a third bursoscopy prior to discharge. In the bursoscopy group, seven (53.8%) were discharged and three (23.1%) were subjected to euthanasia following the first surgery. Three (23.1%) received a second bursoscopic lavage with one discharged, one subjected to euthanasia and one having a third bursoscopic lavage prior to discharge. Overall, 18/24 (75%) followed up cases RTW, 10 (55.5%) from the needle group, eight (44.4%) the bursoscopy group. No statistically significant differences between first surgical technique used and success at first surgery (no subsequent lavage(s) required), survival to discharge or return to work were detected. The main limitations of this study are that it is a retrospective study, has a small population with limited statistical power and potential selection bias. No statistically significant differences existed between the outcomes of the two techniques, contrary to the belief that bursoscopic lavage is superior. Larger, multicentred studies, with greater statistical power are required to further assess this relationship.  相似文献   

高产、抗病转基因抗虫棉品种——中棉所94A915     

范术丽  王龙  庞朝友  魏恒玲  王寒涛  王晖  喻树迅 《中国棉花》2017,44(1):35-35

概述了中棉所94A915的选育经过、特征特性，并总结了其关键栽培技术。  相似文献