不同品种梨新梢木质部细胞的解剖学比较分析

研究‘水晶梨’、‘丰水梨’的细胞解剖学结构,试图为梨树的生理生态特性及其进化提供理论依据。以‘水晶梨’、‘丰水梨’与对照品种‘酥梨’的新梢木质部细胞为试材,对3个梨品种的导管分子、管胞分子以及纤维分子等细胞解剖学特征进行了比较分析。结果表明：‘水晶梨’较‘丰水梨’和‘酥梨’导管细胞上的纹孔大且致密,畸形导管明显比‘丰水梨’和‘酥梨’少。‘丰水梨’导管分子的最大直径较‘水晶梨’和‘酥梨’大,差异达到极显著水平;端尾长度较‘水晶梨’和‘酥梨’短,差异达到极显著水平;纤维分子长度较‘水晶梨’和‘酥梨’无显著差异;纤维分子直径较‘水晶梨’和‘酥梨’小,差异达到极显著水平。与‘酥梨’相比,‘水晶梨’导管的横向运输能力强,‘丰水梨’导管的纵向运输能力强,这些特征有利于提高它们的生态适应性。     

洋县梨黑斑病的发生及其综合防治

正洋县位于陕西省西南部,梨树栽培品种以黄金梨、苍溪雪梨为主,面积达2万亩,年产商品梨果2万吨,产值约4000万元。梨黑斑病又名"裂果病",是该县梨树上重要的病害之一,常引起大量裂果、早期落叶和嫩梢枯死,导致树体生长势减弱、抗病力降低,影响梨的产量和栽培效益,果农须对其危害和防治引起重视。     

抹梢与修剪对柠檬春花秋熟果调控的影响

对柠檬春花期新梢进行抹除(抹梢);修剪柠檬花期过密花枝,同时抹除抽发的新梢(抹梢+修剪),统计分析有叶枝梢花量、无叶枝梢花量、有叶果量、无叶果量、枝梢叶片数量、单株产量。旨在研究抹梢和修剪处理对柠檬春花秋熟果花果调控的影响,为提高柠檬产量及柠檬的花期调控理论提供科学依据。结果表明:不同处理间柠檬带叶枝梢花量和无叶枝梢花量的差异均不显著;不同处理对柠檬有叶果量和无叶果量影响较大。生理落果完成后,不同处理间有叶果量和无叶果量差异显著,均为修剪+抹梢处理最多,抹梢处理次之,对照最少;不同处理对枝梢叶片数量的影响较小,差异不显著;不同处理间柠檬单株产量差异均达到显著或极显著水平。同一年度不同处理单株产量大小依次为:修剪+抹梢抹梢对照,2010、2011年抹梢处理分别比对照增加45.0%、33.8%,修剪+抹梢分别比对照增加86.2%、71.9%。综合考虑,柠檬春花果修剪+抹梢调控效果最好。     

小定额灌溉对‘黄冠’梨生长和果实品质的影响

为提高梨园水分利用率和梨果实品质,2016年3—11月在河北工程大学现代农业示范培训基地以4年生‘黄冠’梨为试材进行田间试验,研究小定额灌溉对梨园土壤含水量、梨树新梢生长量、产量与果实品质、根系分布与数量的影响。结果表明:不同小定额灌溉方式间灌溉区土壤含水量差异显著,沟灌土壤含水量显著高于树盘畦灌和滴灌,平均质量含水量为15.33%,其梨树的新梢生长量也为最大,达到42.25 cm;沟灌产量最高,单果重显著高于滴灌和树盘畦灌;沟灌果实维生素C含量显著高于滴灌和树盘畦灌,滴灌果实糖酸比显著大于沟灌和树盘畦灌,沟灌果实的可溶性固形物含量显著高于滴灌和树盘畦灌;沟灌处理下,梨树吸收根的数量显著高于树盘畦灌和滴灌,分别是它们的3.6倍和2.4倍。综合来看,沟灌是梨园最适宜的小定额灌溉方式。     

梨周年无裙膜避雨栽培主要物候期潜在不利气象因子分析

为克服避雨栽培局域潜在不利气象因子对梨生长发育的影响,采取定点观测记载的方法,分析梨周年避雨栽培主要物候期气象因子变化趋势。结果表明,与露地栽培相比,避雨栽培全年及梨树各主要物候期的日均温偏高、昼夜温差趋大;休眠期≤7.2℃时数累积减少5.57%,差异显著;开花期最低温、≥25℃高温时数提高0.5℃和17.72%,差异均极显著;果实发育中前期和中后期≥35℃超高温、夜间≥25℃时数分别增加25.76%、25.93%和38.73%、37.72%,差异均极显著。避雨栽培下空气湿度偏低且趋稳,开花期(<60%)、果实发育中前期和中后期(<50%)的较低相对湿度的累积时数分别减少3.36%、8.53%、10.56%,其中后2个时期的差异水平显著;而处于100%相对湿度时数分别减少42.78%、56.14%、77.11%,差异均极显著。避雨栽培光照弱化严重,果实发育期<2000 lx光补偿点光强时长增加8.64%,而≥2000 lx光补偿点光强时长减少3.61%。梨周年避雨栽培可改善花期授粉受精条件,创造不利病害发生的生态环境,但会提高梨树因休眠期需冷量不足而出现生长发育障碍的概率,加剧形成光照不足、高温和超高温等不利果实发育的气候环境,应注重选择适宜梨品种,采取合理避雨栽培方式,选用透光率高覆盖材料与高光效整形修剪方法,以及应用地面铺设反光膜、棚内安装补光装置等措施加以克服。     

不同时期、不同级别叶部斑病的发生对玉米产量的影响

利用玉米品种绥玉29,采用人工剪叶模拟玉米叶部病害的发生,在不同熟期依据病害发生级别标准对叶片进行人工处理,研究灌浆期、乳熟初期、乳熟末期、蜡熟期4个时期叶部病害发病对玉米产量的影响,以及在同一时期不同级别病害对玉米产量的影响,得出如下研究结果:在玉米灌浆期、乳熟初期、乳熟末期、蜡熟期随着病害级别的增加,产量呈现不同程度的减少;但在灌浆期减产的幅度最大,且各病害发生后的产量均呈现极显著差异,在蜡熟期随着病害发生级别的增加,减产的幅度最小;随着玉米生育时期的进展,越往后期发病对产量的影响越小;在蜡熟期发病,1级、3级病害发生与对照相比无显著差异,5级、7级、9级病害发生后的产量无显著差异,说明在蜡熟期发生各级别病害对于产量的影响不显著。     

中国梨木虱危害规律的研究

经多年研究,已明确中国梨木虱对梨树的为害分直接为害和间接为害,后者远远大于前者.梨木虱分泌物是链格孢菌和枝孢菌等霉菌的很好的培养基质,在空气相对湿度超过60%以上时,霉菌就在存有分泌物及其残留物的叶片、枝条或果实上附生,生长发育,并产生AA毒素,在霉菌及其毒素的共同作用下,造成梨木虱对梨树的间接危害,使梨叶形成被害斑,进而造成早期落叶,果实形成病斑,进而腐烂.     

不同叶龄施肥对玉米苗期农艺性状的影响

为了探究玉米苗期施肥的最佳叶龄,通过玉米盆栽试验,以玉米株高、茎粗、叶面积、根冠比、干物质重为评价指标,采用SPSS差异显著性分析。试验结果表明:展3叶施肥能显著影响玉米苗期的株高、茎粗、叶面积、干物质积累,其中展3叶施肥处理后的株高分别比展5、6叶施肥处理的株高高9.7cm、12.4cm,达差异显著水平;展3叶与展4叶施肥处理后的茎粗无明显差异,但显著大于展5叶与展6叶施肥处理;通过展3叶施肥处理后的叶面积显著大于展4、5、6叶施肥处理后的叶面积,分别比展4、5、6叶施肥处理大24.65cm2、79.5cm2、84.04cm2,两两比较各处理下的叶面积,差异性达显著水平;在干物质的积累方面,各处理总干重差异显著,其中展3叶施肥与展6叶相比,总干重和根干重均达到极显著水平;而根冠比展5、6叶施肥显著大于展3、4叶施肥。说明不同叶龄施肥是影响玉米苗期生长发育的重要因素之一,其中展3叶为玉米苗期施肥的最佳叶龄。     

ETS有机肥在大白菜、萝卜上的应用效果研究

通过在大白菜和萝卜上施用ETS有机肥,其研究结果表明：在大白菜上喷施ETS有机肥的效果最好,产量最高,为6501．6kg／667m^2,其净菜率为72．5％,较对照高24个百分点,叶球周长较对照增加了21cm,其株型紧凑,结球紧实;在萝卜上喷施ETS有机肥的产量为4151．1kg／667m^2,较对照增产24．3％,株高较对照高5～6cm、块根较对照长7．5-8．5cm、块根粗、单根重比对照增加了175g。二者产量均较对照差异极显著。     

在植株不同水平距离处垂直断根对夏玉米产量形成和籽粒库容特性的影响

以高产夏玉米品种郑单958(浅根型,ZD)和登海661(深根型,DH)为材料,于大喇叭口期(V12)分别在距离植株两侧10 cm、20 cm、30 cm处垂直断根,断根深度60 cm,以不断根处理为对照,共设计8个处理(ZDCK、ZD10、ZD20、ZD30;DHCK、DH10、DH20、DH30),研究了玉米植株两侧不同水平距离处根系对夏玉米籽粒灌浆及产量形成的调控作用。结果表明,ZD10、ZD20与DH10、DH20分别切断24.81%、11.69%与16.82%、7.52%的根系;ZD30与DH30各指标与CK间无显著差异,ZD10、ZD20产量分别下降13.09%、9.10%,显著大于DH10、DH20的产量降幅(9.81%、4.64%),其产量下降原因主要是断根后两品种的穗粒数与千粒重降低,其中ZD20、ZD10穗粒数与千粒重较ZDCK分别下降4.90%、5.60%和4.37%、7.88%,DH20、DH10穗粒数与千粒重较DHCK分别下降3.38%、5.15%和1.15%、4.97%;断根后两品种实际库容与结实率均有不同程度下降;到达最大灌浆速率时的天数(T_(max))、灌浆速率最大时的生长量(W_(max))、最大灌浆速率(G_(max))、籽粒灌浆活跃期(P)、灌浆速率也均下降,断根处理对浅根型品种郑单958的影响更为显著。     

Growth Patterns of Early Maturing Maize Cultivars

Growth patterns of two early maturing maize cultivars were analyzed, harvesting shoots twice weekly in 1983. Until the end of leaf expansion the leaf dry matter accumulation was highly synchronized in both hybrids. After a short cessation leaf dry weight accumulation was resumed at low to medium rates during the main part of August, during September losses prevailed. During these two months fluctuations in rates were frequent and synchronisation between genotypes small. For stems no transitory cessation of dry matter accumulation occurred; synchronisation between genotypes and fluctuation in rates were less than observed for leaf dry matter accumulation. Losses in stem dry weight mostly coincided with rapid ear growth. Ear dry weight accumulation steeply increased during the first three weeks of August. Fluctuations in rates were large during the following 30 days of rapid growth. This period ended by a sharp decline in rates. Phosphofructokinase activity of upper leaves was maximum in early July followed by a first minimum shortly before anthesis; thereafter the average activity did not change much. The hybrid with higher initial shoot growth rates had a higher phosphofructokinase activity at the same time.     

The dynamics of lucerne (Medicago sativa L.) yield components in response to defoliation frequency

The productive life of lucerne (Medicago sativa L.) stands depends on the rate of mortality of individual plants. However, self-thinning of plant populations may be compensated for by increases in other yield components, namely shoots/plant and individual shoot mass. Frequent defoliation reduces lucerne yield but it is unclear whether this is caused by an acceleration of plant mortality or changes in these other yield components. To investigate this, crops with contrasting shoot yields were created using constant 28 or 42-day regrowth cycles applied to a ‘Kaituna’ lucerne crop in Canterbury, New Zealand during the 2002/2003 and 2003/2004 growth seasons. Two further treatments switched from 28 to 42 or 42 to 28 days grazing frequency in mid-summer (4th February) of each year. The annual yield of shoot dry matter (DM) ranged from 12 to 23 t/ha for the treatments defoliated consistently each 28 or 42 days, respectively. Plant population was unaffected by treatments and declined exponentially from 130 plants/m² in June 2002 to 60 plants/m² in September 2004. The dynamics of plant and shoot population were associated with the light environment at the base of the canopy. The slope of the size/density compensation (SDC) of plants was −1.67 for the treatment defoliated each 42 days, near the expected self-thinning slope of −1.5 for stands at constant leaf area index (LAI). Self-thinning of shoots resumed after each defoliation when the LAI reached 2.1 and the transmission of photosynthetically active radiation (PAR_t) was 0.20. At this point the proportion of aerial DM in the tallest (dominant) shoots increased non-linearly from 30 to >80%, due to the mortality of intermediary and suppressed shoots. The average maximum shoot population in each rotation was 780 shoots/m² and unaffected by the decline in plant population due to a compensatory increase from 6 to 13 shoots/plant as the stand thinned. A lower asymptote of 43 plants/m² was estimated as the minimum plant population at which yield component compensation would maintain the productive potential of these ‘Kaituna’ stands. Differences in shoot yield were explained (R² = 0.97) by changes in the individual shoot mass (ISM) that were consistently lowered by frequent defoliation treatments. Frequent defoliations reduced crop productivity by limiting the assimilation of biomass into each individual shoot with negligible impact on shoot appearance rate, the number of shoots per plant at an LAI of 2.1 or the rate of plant population decay. Inter-specific competition for light was proposed as the main factor controlling self-thinning of plants and shoots regardless of their individual C:N status.     

影响梨叶片高频不定梢再生因素的研究

本文研究了基因型、基本培养基、植物生长物质、叶片接种方法及光、暗培养条件等因素对梨叶片不定梢再生的影响。基因型对叶片不定梢再生影响最大,安久和丰水的再生率最高,可达100%,其次为鸭梨,为80%,黄金梨的再生率最低,仅为27.3%。不同基因型其获得最高不定梢再生率所需附加的植物生长物质不同。TDZ比BA更有利于鸭梨叶片的高频不定梢再生,而BA更有利于西洋梨和砂梨叶片的不定梢再生。暗培养3周后再转光下培养比直接光培养有利于不定梢的再生,叶片接种方法对再生率无明显影响。     

甜菜褐斑病发生时间动态规律研究乔志文

摘 要：在摸清甜菜褐斑病发生时间动态规律的前提下,确定甜菜褐斑病化学防治时期,为科学治理甜菜褐斑病提供理论依据。2016—2017年,采用田间定期调查甜菜褐斑病病情指数的方法,探讨甜菜褐斑病发病程度随时间变化规律。结果表明：2016年病害发展时间曲线有4个高峰日,分别7月25日、8月24日、9月3日、9月18日,病情指数分别为：9.33、42.5、55.92、61.46;2017年,病害发展时间曲线经过8月14日、8月19日、8月24日、8月29日4次升高点一直到9月3日,病害发展达到第1个高峰期日9月3日,病情指数分别为7.86、10.75、30.56、36.53、42.88。发病前期（7月上中旬）,降雨是甜菜褐斑病发生蔓延的决定性因子。9月中旬以后, 温度是甜菜褐斑病发生蔓延的决定性因子。第一个高峰期或上升点日期之前为最佳打药时期, 2016年应在7月25日前喷洒杀菌剂,2017年应在8月14日前喷洒杀菌剂。 关键词：甜菜;甜菜褐斑病;病情指数;病害发展时间曲线;时间动态。 中图分类号：S4 文献标志码：A 论文编号：casb17110062     

混合盐胁迫对马蔺幼苗根系构型及生长量的影响

为探讨不同种类盐胁迫对马蔺幼苗生长状况的影响,采用室内培养的方法,研究总质量浓度为0.3%的NaCl、NaHCO₃单盐溶液及其不同配比的混合盐溶液胁迫对马蔺(Iris lactea var. chinensis)幼苗生长量、地上部干鲜重比值、地下部干鲜重比值以及根系构型的影响。结果表明,随着胁迫时间的延长,0.3%NaCl溶液对叶数和株高增长量的影响最小,其次为3种混合盐溶液,各处理在第14天时株高增幅达到最大。经0.3%NaHCO₃处理后的幼苗地上部干鲜重的比值为空白对照的2.17倍,地下部干鲜重则为空白对照的56.61%,随着混合溶液中NaHCO₃浓度的上升,地上部干鲜重比值表现出上升的趋势,地下部干鲜重比值则表现出下降的趋势。经35天处理后,0.3%NaHCO₃胁迫的马蔺幼苗根系总长、根系表面积较对照均显著下降,降幅分别为39.73%、26.08%,而各处理间的根系体积却无显著差异。研究结果显示,0.3%NaHCO₃溶液对马蔺幼苗的胁迫作用最强,2种单盐对根系的胁迫作用强于混合盐胁迫,而0.3%NaCl溶液对生长量的胁迫作用最弱。     

Mechanisms associated with tiller suppression under stagnant flooding in rice

Stagnant flooding (SF) during vegetative growth triggers stem elongation usually at the cost of tiller production in rice, reducing grain yield. To explore physiological mechanisms associated with tillering suppression under SF, three contrasting genotypes (Swarna and Swarna‐Sub1, both sensitive and IRRI154, tolerant) were evaluated under standing water depths of 0, 5, 30 and 50 cm. SF significantly suppressed tiller formation but increased plant height, root biomass, shoot elongation (ratio of plant height before and after flooding), leaf emergency and non‐structural carbohydrate (NSC) concentration (in root–shoot junction) in all genotypes at the early stage of development. Chlorophyll concentration in the upper leaves (upper most fully expanded leaf at top) was higher than in lower leaves (lowest green leaf at base), but decreased under SF in both. SF increased hydrogen peroxide (H₂O₂) at the early stage of treatment, with concomitant increase in malondialdehyde (MDA) production by stems and leaves. MDA concentration in root–shoot junction increased but delayed. Tiller number correlated negatively with plant height, shoot elongation, leaf emergency, MDA concentration in leaves and root–shoot junction, root biomass, and NSC concentration in the root–shoot junction. The results suggested existence of compensatory mechanisms between tiller growth and shoot elongation in rice for resilience under SF, where energy is mainly diverted for shoot elongation to escape flooding. The SF‐tolerant genotype produced less H₂O₂ and maintained energy balance for higher survival and better growth under stagnant flooding.     

套袋梨园中国梨木虱发生特点及防治技术研究

对套袋梨园中国梨木虱的发生特点及防治技术进行了详尽研究。结果表明，该虫人袋的始、盛、末期分别在5月中旬、6月上中旬和8月中旬至9月中旬；套袋的与不套袋的相比，人袋上果时间提前10～19d；虫量平均增加13倍；由为害叶片变成为害套袋果实的主要害虫之一；增加了间接为害途径，且为害症状有显著变化。提出了防治适期和物理、农业、化学的防治措施。     

A comparison of five varieties of Lolium perenne with special reference to the relationship between the root and shoot systems

The growth of five varieties of Lolium perenne was compared while growing in nutrient solution. Differences in shoot growth were found to be due to variations in the rate of tiller production rather than the size of tiller. The size of the individual roots varied with the variety, and it was this variation which largely caused differences in the root growth relative to shoot growth. The larger the root relative to shoot growth the greater was the adverse effect of defoliation.     

Physiological and biochemical adaptive traits support the specific breeding of alfalfa (Medicago sativa) for severely drought-stressed or moisture-favourable environments

The adaptation of alfalfa to moisture-favourable and drought-prone environments and its underlying mechanisms have not been thoroughly investigated despite their crucial importance to maximize the crop breeding progress. The main aim of this study was to support breeding strategies by exploring the relationship of leaf morphophysiological traits assessed in three growth chamber experiments with the adaptive response of five cultivars (Mamuntanas; Demnat 203; Erfoud 1; Prosementi; SARDI 10) that showed large genotype × environment interaction (GEI) across 10 drought-prone to moisture-favourable Mediterranean environments. Changes in shoot and root metabolite profiles across moisture-contrasting conditions were assessed for two cultivars with contrasting adaptation pattern. The cultivar specifically adapted to drought-prone environments (Mamuntanas), compared with that specifically adapted to moisture-favourable environments (Demnat 203), displayed: (i) lower leaf wilting under drought stress; (ii) delayed leaf senescence under stress, assessed as limited chlorophyll reduction either in vivo from upper to central leaves or in vitro from control to polyethylene glycol-treated leaflets, (iii) greater leaf tolerance to desiccation, measured in vitro as less pronounced reduction of leaf dry weight from control to polyethylene glycol-treated leaflets, (iv) smaller leaves, (v) lower early root and shoot growth and (vi) lower leaf stomata density. The other cultivars exhibited different combinations and/or intermediate values of these traits. The metabolite profiles of Mamuntanas and Demnat 203 differed more in shoots than in roots. Mamuntanas accumulated more amino acids than Demnat 203 under moisture-favourable and drought conditions. The distinct and partly incompatible combination of traits featuring the cultivars that maximized the crop yield in favourable or drought-prone conditions (Mamuntanas and Demnat 203) improves our understanding of traits contributing to large GEI across moisture-contrasting environments and support the breeding for specific adaptation to either condition. We identified a few inexpensive morphophysiological traits that could be used for early selection targeting drought-prone environments.     

去叶处理对萝卜生长及产量的影响

在萝卜生长早期进行去叶处理,研究对中后期生长及产量的影响。结果显示,去叶后,净同化率明显下降,根冠比下降,比叶重降低,根、叶相对生长率降低,经济系数也有一定程度的下降,另外根直径与长度之比指标显示,肉质根膨大受到明显抑制而变小,始终不能恢复到对照水平,从肉质根减产百分率看各处理与对照相比减产非常明显。试验结果证实萝卜早期去叶对植株生长及产量形成有重要影响。