A longitudinal study of the effect of time on the matching performance of a retinal recognition system for lambs

While there is strong evidence supporting retinal vascular pattern as a distinctive marker for sheep, it would be advantageous to get an insight into its robustness; in other words, to determine whether retinal recognition of young animals (lambs) can reach as good a matching performance as the one demonstrated for adult sheep. To this aim, a longitudinal study was devised to observe the evolution of matching scores (ms) of lamb retinal images (n = 38) acquired from 1 to 22 weeks after birth. It was observed that four lamb retinas (out of 38) underwent slight curving of one or two secondary arteries, which ceased by the time they were 6–8 weeks old. However, this slight artery curving did not affect matching performance. A random effects statistical model demonstrated that lamb age had an effect (P < 0.01) on the matching scores produced using this commercially available retinal recognition system. As lambs grew older (larger eyes) and they became easier to handle, retinal images of progressively better quality could be obtained in a more consistent way; and thus matching scores increased from an average of 86 at the first week of life, up to an average of 96 by week 8. Dunnett simultaneous tests of means indicated that no further improvement in matching score took place once lambs were at least 6–8 weeks old, meaning that the retinal image quality became by then optimal and consistent. Although the variable retinal image quality of younger lambs (1–4 weeks old) caused a reduction in matching score, they did not lead to false non-matches in any case (considering a cut-off matching score of 70 for acceptance of a positive match). Therefore, the results of these trials have shown that, with the available technology, retinal images can be used as a robust biometric marker of lambs from 1 week of age.     

Characterization of ethylene biosynthesis and its regulation during fruit ripening in kiwifruit,Actinidia chinensis ‘Sanuki Gold’

Ethylene biosynthesis in kiwifruit, Actinidia chinensis ‘Sanuki Gold’ was characterized using propylene, an ethylene analog, and 1-methylcyclopropene (1-MCP), an inhibitor of ethylene perception. In fruit harvested between a young stage (66 days after pollination) (DAP) and an early commercial harvesting stage (143 DAP), 2 days of exposure to propylene were sufficient to initiate ethylene biosynthesis while in fruit harvested at commercial harvesting stage (154 DAP), 4 days of propylene treatment were required. This observation suggests that response of ethylene biosynthesis to propylene treatment in kiwifruit declined with fruit maturity. Propylene treatment resulted in up-regulated expression of AC-ACO1, AC-ACO2, AC-SAM1 and AC-SAM2, prior to the induction of AC-ACS1 and ethylene production, confirming that AC-ACS1 is the rate limiting step in ethylene biosynthesis in kiwifruit. Treatment of fruit with more than 5 μL L^?1 of 1-MCP after the induction of ethylene production subsequently suppressed ethylene production and expression of ethylene biosynthesis genes. Treatment of fruit with 1-MCP at harvest followed with propylene treatment delayed the induction of ethylene production and AC-ACS1 expression for 5 days. These observations suggest that in ripening kiwifruit, ethylene biosynthesis is regulated by positive feedback mechanism and that 1-MCP treatment at harvest effectively delays ethylene production by 5 days.     

短密木霉菌株GAS1-1的分离鉴定、拮抗作用及其生物学特性

为了解短密木霉Trichoderma brevicompactum对植物病害的生防作用及其生物学特性,利用稀释平板分离法从甘肃省景泰县马铃薯连作田植株根际土壤中分离获得1株木霉菌株GAS1-1,经形态观察、rDNA-ITS和EF-1α序列分析明确其分类地位;用生物学方法研究该菌的营养生长和产孢条件;采用对峙培养法测定该菌株对5种植物病原真菌的抑制作用。结果表明,基于形态学特征和基因序列分析结果,菌株GAS1-1被鉴定为短密木霉Trichoderma brevicompactum,为甘肃省木霉新记录种。该菌株对玉米镰孢茎腐病菌Fusarium graminearum、玉米穗腐病菌F. verticillioides、棉花枯萎病菌F. oxysporum、玉米腐霉茎腐病菌Pythium inflatum和灰葡萄孢霉Botrytis cinerea均具有较好的拮抗效果,尤其对玉米腐霉茎腐病菌的抑制作用最好,抑菌率达100.00%。该菌株营养生长和产孢的最适碳源和氮源分别为葡萄糖和酵母膏;其在15～35℃均可生长,菌丝最适生长温度为30℃,最佳产孢温度为25℃;在pH 5～12的培养基上菌丝均可生长,菌丝最适生长和产孢的pH均为5;24 h黑暗条件下菌丝营养生长最快,12 h光暗交替条件有利于产孢;孢子致死温度为69℃,10 min。表明短密木霉菌株GAS1-1具有较好的生防应用潜力。     

两种基因型龙葵对镉胁迫的生理响应及镉吸收差异

采用盆栽试验,通过研究不同浓度镉(0、5、25、50、100μg·g-1)胁迫下红果龙葵和少花龙葵幼苗根、茎和叶的生物量变化、镉吸收量、镉转移率、镉富集系数和叶片抗氧化酶(SOD、POD)活性、叶片可溶性蛋白和游离脯氨酸含量等指标的变化,比较2种基因型龙葵富集镉的差异。结果表明,2种基因型龙葵富集重金属镉存在明显差异。与对照相比,在Cd胁迫浓度≥25μg·g-1时,2种龙葵的生物量显著下降(P<0.05),而少花龙葵的下降趋势较红果龙葵小;随着Cd胁迫浓度的增加,2种龙葵根、茎和叶的Cd吸收量显著上升(P<0.05),且根部Cd含量高于茎和叶,而少花龙葵的根、茎和叶中的Cd含量均高于红果龙葵,2种龙葵的镉转移率和富集系数除5μg·g-1Cd胁迫外,均小于1,且少花龙葵对镉转移率和镉富集系数均大于红果龙葵。2种龙葵叶片可溶性蛋白、游离脯氨酸含量以及抗氧化酶(SOD、POD)活性均表现为先上升后下降,均表现为少花龙葵上升幅度大而下降幅度较小。综合各项指标表明,2种龙葵均不是Cd的超积累植物,少花龙葵的耐Cd胁迫能力较红果龙葵强。     

多功能改土剂配方筛选及对河西内陆灌区制种玉米田的改土培肥效应

[目的]研究甘肃省河西内陆灌区多功能改土剂配方筛选及对制种玉米田改土培肥效应的影响,为该区制种玉米产业可持续发展提供技术支撑。[方法]选择甘肃省酒泉市连续种植制种玉米15a基地,采用田间试验方法,开展了多功能改土剂配方筛选及对河西内陆灌区制种玉米田改土培肥效应的研究。[结果]多功能改土剂最佳配方组合:玉米专用肥、聚乙稀醇、有机废弃物组合肥、保水剂重量配比为0.032 2∶0.001 4∶0.965 5∶0.000 9。不同剂量多功能改土剂施用量与制种玉米田孔隙度、团聚体、持水量、有机质和速效氮磷钾呈显著的正相关关系;与容重、pH值呈显著的负相关关系。施用多功能改土剂与传统化肥比较,制种玉米田容重和pH值分别降低6.88%和5.10%;总孔隙度、毛管孔隙度、非毛管孔隙度和团聚体分别增加10.46%,10.49%,10.48%和11.75%;饱和持水量、毛管持水量和非毛管持水量分别增加10.47%,10.46%和10.48%;有机质、碱解氮、速效磷、速效钾和阳离子交换量(CEC)分别增加9.03%,1.11%,4.12%,3.82%和32.03%;真菌、细菌、放线菌和菌体总量分别增加121.19%,34.95%,20.25%和28.57%;蔗糖酶、脲酶、磷酸酶和多酚氧化酶分别增加44.74%,44.73%,38.46%和62.50%。[结论]施用多功能改土剂,改善了制种玉米田理化性质和生物学性质,提高了酶活性及持水量和制种玉米产量。     

施用富Cu猪粪后潮土-小麦系统Cu的传递与积累

以华北地区典型土壤潮土为供试土壤,将猪粪(施用量占风干土重的0%,1%和3%)和不同Cu浓度(0,100,200,400,600和800 mg kg-1土)的CuSO4溶液腐化后与土壤混合均匀进行盆栽试验,以研究施用富Cu猪粪对土壤和小麦各器官(根、茎叶和籽实)Cu积累及对潮土—小麦系统Cu迁移转化的影响。结果表明,土壤全Cu、有效态Cu和小麦植株各器官Cu浓度均随着外源Cu浓度的增加而显著增加,在相同外源Cu浓度条件下,成熟期各指标浓度相对拔节期有所下降。外源Cu只有极少量从土壤向小麦转移,且在小麦各器官Cu浓度顺序为根>>茎叶/籽实。相对于拔节期,小麦成熟期根部Cu积累量显著上升,茎叶Cu积累量无显著变化,但根部和茎叶Cu浓度均显著下降。施用1%猪粪明显降低了Cu的可移动性,而3%猪粪在一定程度上增加了Cu的传递与积累。当外源Cu浓度≥200 mg kg-1时,0%和3%猪粪施用的处理籽实中Cu浓度超过了人体能接受的Cu毒性极限(20 mg kg-1),施用1%猪粪则潜在的降低了Cu在籽实中的积累。     

洗涤剂对豌豆根尖细胞的致畸效应

为研究洗涤剂对豌豆(Pisum sativum)是否产生细胞毒性和遗传毒性效应,以豌豆根尖细胞为材料,利用微核技术,用不同稀释倍数的洗涤剂对根尖处理24和48 h,设4个稀释倍数分别为200倍、100倍、10倍、5倍,统计豌豆根尖细胞有丝分裂指数、微核率及染色体畸变率,并进行显微摄影。结果表明,随洗涤剂原液稀释倍数的降低和处理时间的延长,根尖细胞有丝分裂指数明显下降,并具有明显剂量-时间效应关系;微核率和染色体畸变率先升高后下降,不具有剂量-时间效应。稀释不同倍数洗涤剂能引起根尖细胞染色体桥、微核等多种染色体畸变类型,造成根尖细胞染色体损伤。洗涤剂对豌豆根尖细胞具有一定的遗传毒性。     

北方寒旱区白菜型冬油菜安全越冬的临界指标分析

利用2011-2014年北方13个省、市、区48个不同生态点试验的数据,分析不同品种在不同生态点的越冬率、产量变化,越冬率与产量的相关性,旨在研究白菜型冬油菜在北方不同生态区的越冬安全性,确定北方冬油菜通用的安全越冬的越冬率临界值,明确影响北方冬油菜越冬率的主要因子。结果表明,不同白菜型冬油菜品种在北方不同生态地区越冬率差异较大,产量也差异较大,越冬率变幅为10%~99%,强抗寒品种越冬率>70%。回归分析表明,越冬率与产量存在明显的线性正相关,回归方程符合y=ax+b, 当越冬率<70%时,产量随越冬率的增加而增加,当越冬率为70%时单位面积产量基本趋于稳定, 越冬率大于70%时,越冬率对产量的影响不明显。协方差分析表明,与冬油菜越冬率相关性最为密切的因子是品种,其次是极端最低气温、冬季气温、年均气温、≤0℃的冬季负积温、纬度、经度等。因此,70%的越冬率可作为北方地区冬油菜通用安全越冬的越冬率临界值,采用强抗寒品种,极端最低气温–31.79℃、冬季气温–7.20℃、年均气温6.38℃、负积温–997.57℃,纬度低于44.83°,经度高于80.34°是保证冬油菜安全越冬的必要条件。     

有机物料组合肥还田对耕地质量及甜菜品质和效益的影响

在甘肃省张掖市甘州区明永乡甜菜种植基地上,采用田间试验方法,连续3a进行了有机物料组合肥还田对耕地质量及甜菜品质和效益影响的研究.结果表明:羊粪+改性糠醛渣+葵花籽饼组合肥有利于提高土壤的总孔隙度、>0.25 mm团聚体、持水量和CEC,降低容重、pH值和全盐含量,与传统化肥比较,土壤总孔隙度和>0.25 mm团聚体分...     

白芥离体快繁体系的建立

以白芥幼苗为外植体,MS和1/2MS为基本培养基分别加入不同浓度的6-BA、NAA和KT进行白芥离体再生技术体系研究.结果表明:以白芥幼苗为外植体进行培养,其不定芽增殖效果较好.6种不定芽增殖培养基增殖效果存在明显差异,其中最适宜的芽增殖培养基是MS+1mg/L 6-BA+1mg/L KT,侧芽及不定芽生长迅速、且旺盛,2周后不定芽平均增殖到10个;大量元素含量对幼苗的壮苗具有显著效应,其中3MS培养基的壮苗效果最好,培养21d的苗较对照明显变粗壮;组培苗接种在1/2 MS+0.133mg/L NAA的培养基上诱导生根的效果最佳,茎段培养约15d时发现白色根,主根较多、细长,有侧根,每单株可达7条根.