云南铁壳麦穗发芽抗性及成因初步研究

为给云南铁壳麦在小麦抗穗发芽育种中的应用提供依据,以收获后保存于-20℃和常温下的云南铁壳麦为材料,研究了其穗发芽抗性的多样性及其形成因素。结果表明,32份云南铁壳麦平均穗发芽率为14.3%,穗发芽度为6.01%,具有很强的穗发芽抗性;整粒平均发芽率为24.3%,发芽指数为21.8%,表现出较强的休眠性;其中有3份铁壳麦休眠性较弱,2份在常温保存3个月后发芽率依然低于50%,休眠期较长。半粒的平均发芽率和发芽指数分别为40.2%和28.7%,推测休眠性与种皮以及种子内的抑制物质有关。在颖壳+籽粒发芽实验中,-20℃保存材料的平均发芽率为11.8%,发芽指数为9.4%,说明颖壳浸出液对籽粒发芽有较强的抑制作用;常温下保存材料的平均发芽率在第1、第3、第5和第7天分别为27.4%、7.5%、1.9%和0.6%,8 d后仍有34.1%的籽粒未能发芽,说明随着实验时间的延长,颖壳中抑制物质的浸出液浓度逐渐增加,抑制作用加强。从抑制率来看,种皮抑制率＞颖壳机械抑制率＞颖壳浸出物抑制率,表明云南铁壳麦的穗发芽抗性主要来自于种子的强休眠性,颖壳的机械作用和浸出物的抑制作用也是主要的形成因素。     

用中国春双端二体分析“云南小麦”染色体构成

 用中国春双端二体（Double ditelosomic）系列作母本分别和“云南小麦”杂交，并对所得21个组合F#-1代进行端体配对分析。其中在13个组合中观察到中国春的两个端体同时和“云南小麦”相应染色体配对形成异型三价体（ttl'）的PMC频率达77.7-93.7%，说明“云南小麦”的这13条染色体和中国春的相应染色体间的差异很小。在另外8个组合（包括2A、7A、2B、4B、5B、6B、1D、5D）中，出现ttl'、tl'+t'和t'+t'构型的PMC频率分别为35.0-73.7%、21.5-55.0%和1.0-10.0%，表明“云南小麦”这8条染色体和中国春相应染色体之间在某个臂上存在一定程度的分化。在绝大多数组合中都观察到不包含端体的三价体、四价体，这表明在“云南小麦”的某些染色体可能发生了易位变异。     

Dispersal of Eastern King Prawn larvae in a western boundary current: New insights from particle tracking

Patterns in larval transport of coastal species have important implications for species connectivity, conservation, and fisheries, especially in the vicinity of a strengthening boundary current. An Ocean General Circulation Model for the Earth Simulator particle tracking model was used to assess the potential dispersal of Eastern King Prawn (EKP) larvae Melicertus (Penaeus) plebejus, an important commercial and recreational species in Eastern Australia. Particles were exposed to a constant natural mortality rate, and temperature‐dependent growth (degree‐days) was used to determine the time of settlement. Forward and backward simulations were used to identify the extent of larval dispersal from key source locations, and to determine the putative spawning regions for four settlement sites. The mean dispersal distance for larvae was extensive (~750–1,000 km before settlement), yet the northern spawning locations were unlikely to contribute larvae to the most southern extent of the EKP range. There was generally great offshore dispersal of larvae, with only 2%–5% of larvae on the continental shelf at the time of settlement. Our particle tracking results were combined with existing site‐specific reproductive potentials to identify the relative contributions of larvae from key source locations. Although mid‐latitude sites had only moderate reproductive potential, they delivered the most particles to the southern coast and are probably the most important sources of larval EKP for the two southern estuaries. Our modelling suggests that mesoscale oceanography is a strong determinant of recruitment success of the EKP, and highlights the importance of both larval dispersal and reproductive potential for understanding connectivity across a species’ range.     

Plateletcrit is superior to platelet count for assessing platelet status in Cavalier King Charles Spaniels

Background: Many Cavalier King Charles Spaniel (CKCS) dogs are affected by an autosomal recessive dysplasia of platelets resulting in fewer but larger platelets. The IDEXX Vet Autoread (QBC) hematology analyzer directly measures the relative volume of platelets in a blood sample (plateletcrit). We hypothesized that CKCS both with and without hereditary macrothrombocytosis would have a normal plateletcrit and that the QBC results would better identify the total circulating volume of platelets in CKSC than methods directly enumerating platelet numbers.
Objectives: The major purpose of this study was to compare the QBC platelet results with platelet counts from other automated and manual methods for evaluating platelet status in CKCS dogs.
Methods: Platelet counts were determined in fresh EDTA blood from 27 adult CKCS dogs using the QBC, Sysmex XT-2000iV (optical and impedance), CELL-DYN 3500, blood smear estimate, and manual methods. Sysmex optical platelet counts were reanalyzed following gating to determine the number and percentage of normal- and large-sized platelets in each blood sample.
Results: None of the 27 CKCS dogs had thrombocytopenia (defined as <164 × 10⁹ platelets/L) based on the QBC platelet count. Fourteen (52%) to 18 (66%) of the dogs had thrombocytopenia with other methods. The percentage of large platelets, as determined by regating the Sysmex optical platelet counts, ranged from 1% to 75%, in a gradual continuum.
Conclusions: The QBC may be the best analyzer for assessing clinically relevant thrombocytopenia in CKCS dogs, because its platelet count is based on the plateletcrit, a measurement of platelet mass.     

假冒檀香紫檀的2种木材的研究与鉴定

以苏州某家具厂提供的2个家具构件(记为A和B)为对象,对家具构件取样、切片、染色以及对标准三切片进行观察、鉴定。结果表明,A家具构件树种为豆科印度苏木属的二出印度苏木,B家具构件树种为使君子科榄仁树属毛榄仁。对比二出印度苏木、毛榄仁与檀香紫檀的构造特征,发现三者的差异主要存在于弦切面。对檀香紫檀、二出印度苏木、毛榄仁3种木材的红外光谱图进行比较,发现二出印度苏木和毛榄仁的半纤维素有一定程度的降解,二出印度苏木与檀香紫檀、毛榄仁在多糖结构上存在差异。     

不同刻芽处理对“中秋王”苹果枝条萌芽成枝的影响

以3年生"中秋王"苹果1年生枝条为试材,设置全刻芽(T1)、基部刻芽(T2)、中部刻芽(T3)、上部刻芽(T4)4种刻芽方式,以不做刻芽处理的枝条为对照(CK),研究不同刻芽处理对"中秋王"苹果枝条萌芽成枝的影响,以期筛选"中秋王"苹果适宜的刻芽促枝方式,为"中秋王"苹果生产中刻芽促枝尽快成形提供参考依据。结果表明:刻芽处理可显著提高苹果枝条萌芽率、成枝力(P<0.05),枝条萌芽率与成枝力呈极显著正相关关系(P<0.01),与短枝率呈显著负相关关系(P<0.05),与长枝率呈显著正相关关系(P<0.05)。对"中秋王"苹果进行刻芽处理对树体枝条萌芽率、成枝力、枝类组成作用显著。从改善苹果萌芽成枝、整形效果以及省工省力等方面综合分析认为,最适刻芽方式为中部刻芽。     

Chiari 1/syringomyelia complex in a King Charles Spaniel

A 9-year-old King Charles Spaniel presented with a history of progressive forelimb weakness and paroxysmal involuntary flank scratching over a 2-year period. Neurological examination suggested a myelopathy of C1 to C4 spinal cord segments. Advanced imaging studies revealed hydrocephalus, caudal herniation of part of the caudal lobe of the cerebellum through the foramen magnum and marked syrinx formation to the level of the caudal thoracic spine, resembling Arnold-Chiari malformation with secondary hydromyelia in humans. Mechanical obstruction at the craniocervical junction, altering CSF flow dynamics, may lead to syrinx formation. Response to diuretic therapy was moderate but surgical decompression may offer better long term prognosis.     

Effect on Resistance to Tylenchulus semipenetrans of Hybrid Citrus Rootstocks Subjected to Continuous Exposure to High Population Densities of the Nematode

Experiments simulating interplanting of resistant rootstocks with susceptible rootstocks that maintain high population densities of Tylenchulus semipenetrans in field soil were carried out in microplots at two locations, and in an naturally infested orchard. Selections of Cleopatra mandarin (03) × Poncirus trifoliata (01) 03.01.5 and 03.01.13, Citrus volkameriana (23) × P. trifoliata 23.01.17, Troyer citrange (02) × Cleopatra mandarin 02.03.24, Troyer citrange × Common mandarin (04) 02.04.18, King mandarin (05) × P. trifoliata 05.01.7, and Carrizo citrange were exposed to continuous high population densities of a population of the Mediterranean biotype of T. semipenetrans. The selection 23.01.17 retained its resistance in the microplots and in the field (< 1.2% females and eggs per gram fibrous root of those on Carrizo citrange). The selection 03.01.5 also retained its resistance in the microplots at Moncada (< 0.5% females and eggs per gram fibrous root of those on Carrizo citrange) but numbers of females and eggs per gram fibrous root were 27% and 22% at Amposta, and 139% and 18% in the orchard of those on Carrizo citrange, respectively. The selection 05.01.7 supported equal number of females and 43% eggs per gram fibrous root of those on Carrizo citrange in the nematode-infested orchard. The remaining selections supported high populations of T. semipenetrans.     

Short-Term Control of an Invasive C4 Grass With Late-Summer Fire

Yellow bluestem (Bothriochloa ischaemum [L.] Keng var. songarica [Rupr. ex Fisch & C.A. Mey] Celarier & Harlan) is a non-native, invasive C₄ grass common in southern Great Plains rangelands. We measured the effects of a single late-summer (September 2006) fire on yellow bluestem at two sites in central Texas (Fort Hood and Onion Creek). At Fort Hood, relative frequency of yellow bluestem in burned plots decreased from 74 ± 4% (preburn; mean ± standard error) to 9 ± 2% (2007) and remained significantly lower compared with unburned plots through 2009 (burned: 14 ± 2%; unburned: 70 ± 14%). At Onion Creek, yellow bluestem initially decreased from 74 ± 5% (2006) to 32 ± 7% (2007). Yellow bluestem recovered substantially by 2009 (67 ± 10%) but was still significantly lower than in unburned transects (96 ± 1%). Relative frequency of other graminoids increased significantly in burned plots (compared with preburn values) at Fort Hood (preburn: 11 ± 4%; 2009: 29 ± 7%) but not at Onion Creek (preburn: 24 ± 6%; 2009: 22 ± 7%). Frequency of forbs increased dramatically in the first growing season after fire (Fort Hood: 15 ± 2% to 76 ± 3%; Onion Creek: 2 ± 2% to 45 ± 5%), then decreased through the third growing season (Fort Hood: 57 ± 6%; Onion Creek: 11 ± 4%). Key differences between the sites include much higher biomass at Fort Hood than at Onion Creek (8 130 kg ? ha^-1 vs. 2 873 kg ? ha^-1), more recent grazing at Onion Creek (ending in 2000 vs. before 1996 at Fort Hood), and higher rainfall after the Onion Creek burn (214 mm in 20 days vs. 14 mm). Late-summer fire can temporarily decrease yellow bluestem frequency, but effects vary with site conditions and precipitation. Restoring dominance by native grasses may require additional management.