华北冬小麦开花及成熟期变化特征分析

利用华北平原59个农业气象观测站1981—2010年冬小麦生育期资料,分析了该区域冬小麦在气候变暖背景下开花期和成熟期的变化趋势特征。研究结果表明：近30年来,华北平原冬小麦开花期和成熟期均发生了明显变化。相对1980s而言,1990s开花期普遍提前2～5 d,成熟期提前1～6 d左右,2000s开花期则一般提前3～9 d,成熟期提前1～7 d左右。因此,随着年代推进,华北平原冬小麦开花期和成熟期提前趋势在进一步加剧。相对1980s而言,1990s生育期等值线普遍北移,而2000s等值线进一步北移的趋势更加明显。研究发现,3—5月月平均气温升高是开花期和成熟期提前的一个重要影响因素。     

When and why do smallmouth bass abandon their broods? The effects of brood and parental characteristics

Abstract Variation in brood abandonment was explored by conducting partial brood removals from smallmouth bass, Micropterus dolomieu Lacepède, nests in two north temperate lakes. In both lakes, percent of the brood removed had no effect on nest failure rates. Nest failure prior to offspring swim‐up was more common, but unrelated to brood size after removal, in the lake with higher post‐spawning mortality and lower growth and fecundity. Brood size after removal was negatively related to nest failure in the lake with high survival, growth and fecundity. Nests guarded by young males failed more frequently than those of old males, and young broods failed more frequently than old broods. Dynamic programming and logistic regression models developed to predict nest fate worked better for the lake with selective pressures that theoretically favoured abandonment (e.g. high post‐spawning mortality). Both models identified male age and brood age as important factors in predicting nest fates. Because nest success is related to the age of the parent, this could have consequences for overall nest success for populations with different demographics.     

不同施肥处理对湿加松早期生长及感病指数的影响

调查了福建省德化葛坑国有林场4种不同施肥处理后,2、3、4年生湿加松树高、胸（地）径和病害指数变化情况。结果表明,（1）不同施肥处理对湿加松早期树高、胸（地）径和松感病指数均产生显著影响,各生长年度树高、胸（地）径生长大小依次为：施氮磷钾复合肥与硼砂〉施氮磷肥与硼砂〉施氮磷肥〉对照（不施肥）,而感病指数大小则为：对照（...     

壮芽灵对烤烟种子的处理效应

对云烟85、K326和红花大金元3个品种进行不同成熟期种子活力测定及壮芽灵浸种处理。结果表明：完熟期的种子活力高于褐熟期和枯熟期；壮芽灵处理种子中，以稀释1000倍，浸种24小时的效果较好，可提高中、低等活力水平的烤烟种子的活力，而对高活力烤烟种子则有轻微的抑制作用。本法对提高中、低等活力水平的烤烟具有明显作用。     

冀鲁豫夏玉米区玉米杂交种群体生育型演变──Ⅰ．演化阶段与演进基本途径

在实验基础上,从群体生育型演变进化角度分析了冀鲁豫夏玉米区六十年代初至九十年代初三十年间玉米杂交种种性提高的自然现象,明确了玉米杂交种群体生育型以产量行为与抗斑一倒行为的持续改良为基本途径演进。极端杂交种株粒重提高了４８．４％,叶斑指数与倒折率分别下降了４．３与１．２个百分点。演进过程界定为四个演化阶段：Ⅰ．六十年代,以新单１、白单４为代表;Ⅱ．七十年代前期,以群单１０５、丹玉６为代表;Ⅲ．七十年代后期至八十年代初,以郑单２、博单１为代表;Ⅳ．八十年代前期至九十年代初,以烟单１４和掖单２为代表。玉米杂交种群体生育型演变进化遵循“多元动态代谢结群,系统吐纳循序渐进”的生物进化规律。     

A plant ideotype for Bromus inermis Leyss. in Western Canada

Summary This study relates the yield of two harvests of Bromus inermis Leyss. to tiller type and morphology. Tillers were classified as being nonelongated, elongated and headed. At four times during the growing season, observations were made of tiller density; individual tiller weight; leaf number, area and weight; stem length, area and weight; leaf to stem ratio; specific leaf weight; head area and weight.Results showed that there was a pattern of tiller control over yield which was different for each of the two harvests. Stem characters contribute more to yield than leaves. Growth, early in the season, had a prominent effect on yield of the first harvest and also influenced the second harvest. Height at the time of each harvest was highly predictive of yield of the respective harvests. A morphological ideotype for bromegrass harvested twice in a season was described.     

新疆伊犁某牛场不同生长期牛粪源大肠杆菌耐药性调查

为了调查新疆伊犁某牛场不同生长期牛粪源大肠杆菌对临床常用抗菌药物的耐药情况。从该牛场分别采集育肥牛、繁育牛、加育牛和未繁育牛的粪样。采用微量肉汤稀释法,对分离出的大肠杆菌进行最小抑菌浓度测定。结果表明,育肥牛、繁育牛、加育牛和未繁育牛粪源大肠杆菌分离率均为100%,不同生长期的牛源大肠杆菌对氨苄西林均耐药,耐药率分别为4.0%、8.6%、6.7%、20.0%;对安普霉素都较为敏感。繁育牛和加育牛粪源大肠杆菌耐药种类较多,未繁育牛粪源大肠杆菌对比其他生长期牛粪源菌耐药较严重,不同生长期的牛粪源大肠杆菌多重耐药情况不太严重,主要为0耐、1耐;新疆伊犁该牛场对临床常用抗菌药物的耐药程度不同,耐药程度虽然不高,但在养殖生产中需注意合理用药。     

CO2 and ozone effects on canopy development of potato crops across Europe

This paper describes the effects of elevated CO₂ (550 and 680 μl l⁻¹) and O₃ (60 nl l⁻¹ O₃ as an 8 h mean), alone or in combination, on canopy development and senescence in potato (Solanum tuberosum L. cv Bintje) across a range of European agro-climatic conditions. The assessments were made within the European CHIP project (CHanging climate and potential Impacts on Potato yield and quality) that was conducted for two growing seasons (1998 and 1999) in free air CO₂ enrichment systems (FACE) and open-top chamber facilities (OTCs) at seven European sites. A comparison of chambered and unchambered experimental plots was included to examine the effects of chamber enclosure. Phenological growth stages, plant height, leaf area index (LAI) and the number of green and yellow leaves were recorded non-destructively throughout the growing season and by a destructive intermediate harvest at maximum leaf area (MLA). In the dynamic growth analysis CO₂ and O₃ effects were studied over three developmental stages: canopy expansion, full canopy and canopy senescence. Chamber enclosures promoted potato crop development (taller plants, more leaves) during the initial growth stages and led to a faster decline of LAI and a higher number of yellow leaves. The growth in ambient plots varied between sites and seasons, as did the scale of the treatment responses. Despite the large background variation, some overall treatment effects could be detected across all sites. Both levels of increased CO₂ reduced final plant height in comparison to ambient concentrations, which indicates a premature ending of the active plant growth. At the stage of full canopy and crop senescence the average number of green leaves was significantly (P<0.05) decreased by 680 μl l⁻¹ CO₂ (OTC experiments) and LAI showed the same tendency (P=0.07). As there was however no indication of a decreased leaf formation during initial growth and at full canopy, this must have been due to an earlier leaf fall. In the FACE experiments LAI had already began to decline at the stage of full canopy at 550 μl l⁻¹ CO₂ but not in ambient CO₂ (DAE×CO₂, P<0.05). These observations strongly indicated that elevated CO₂ induced a premature senescence during full canopy. O₃ did not have an overall detrimental effect on crop development during initial growth nor at full canopy, but did induce a faster reduction of LAI during crop senescence (DAE×O₃, P<0.05). Final plant height was not affected by O₃. There were few CO₂×O₃ interactions detected. There was a suggestion (P=0.06) that O₃ counteracted the CO₂-induced decrease of green leaves at full canopy, but on the other hand during crop senescence the decline of LAI due to elevated O₃ was faster at ambient compared to elevated CO₂ (P<0.05). These responses of canopy development to elevated CO₂ and O₃ help to explain the treatment responses of potato yield within the CHIP project at sites across Europe.     

1980～2002年中国农地利用变化的时序特征

该文依托1980～2002年的全国农产品成本收益资料与中国农业统计年鉴等基础资料，以农地利用过程中的主要农作物为例，对农地利用过程中集约度、播种面积与耕地撂荒变化的时序特征及其驱动因素进行了研究。结果表明：近20多年来，中国农地利用的集约度与总播种面积均有不断提高与扩大的总体趋势，但在扩大过程中却有三次显著下降变化，在集约度下降时期(1984～1986年、1992～1993年、1997～1999年)，农作物播种面积明显缩小，农地弃耕撂荒现象开始显著增加；导致这些变化的根本原因同农地利用过程中成本要求与土地要素纯收益的变化密切相关，但在时间响应上，由于农户要经过一个“观望-权衡-行动”的响应过程，从而往往滞后1～3年。     

温室长季节栽培番茄发育动态模拟模型的研究

根据番茄生物学特性、发育阶段有效积温恒定的原理和多年的栽培经验,对温室长季节栽培番茄的发育阶段进行划分,其生长发育阶段包括播种期、幼苗期、开花座果期、果实膨大期、果实采收初期、果实采收盛期和果实采收末期.将不同播期各生育阶段的生长度日的平均值确定为建模过程中的参数Ai自幼苗期至果实采收末期分别为710.5、110.5、152.3、302.9、245.6、2156.7、200.5度日.确定了发育阶段有效积温参数后,建立了温室番茄长季节栽培的发育动态模拟模型,系统的预测番茄发育阶段.模型检验结果表明,温室番茄发育动态模拟模型具有较高的精确性、机理性和实用性.