Characteristics of photosynthesis and conductance of potato canopies and the effects of cultivars and transient drought

Gas-exchange characteristics of potato (Solanum tuberosum L.) canopies were determined with crop enclosures under condition of optimal water supply, during soil water depletion, and during recovery from drought-stress. The plants were grown under a rainshelter in large containers with 2-m² surface area. Control plants received water throughout the growth period. In Expt. 1, transient drought was imposed by interrupting water supply completely for 22 days. During the 33-day period of drought treatment in Expt. 2, the stressed plants received half the amount of water that was given to the control plants (irrigations 2–3 times per week).

During soil water depletion, stomatal conductance of the canopy was reduced earlier and more than photosynthesis. This resulted in a lower internal carbon dioxide concentration in the leaves of stressed plants and a higher ratio between photosynthesis and stomatal conductance. The value of that ratio increased as soil water potential dropped.

Water-use efficiency ( ) increased during drought stress. The cultivar Bintje showed a larger ratio between photosynthesis and stomatal conductance of the canopy and a higher than cv. Saturna, both for optimal water supply and during drought stress.

Photosynthesis and conductance of the canopy started to recover immediately upon rewatering, even when relative values had declined to 20–30% during the preceding stress period. After release from stress, the leaves in the top layer of the canopy had a higher stomatal conductance in treated plants than in control plants.     

Preparation and characterization of fibers of waste and fresh polyethylene terephtalate and mixtures of them

Textile fibers were obtained from secondary polyethylene terephtalate (PET) and its mixtures with primary PET at initial orientation of 18000–33000 %, rate of additional orientation drawing 3.5–6.5 times and temperature of thermal fixation 363–413 K. The fibers’ tensile strength was found to decrease and elongation at break to increase with the decrease of their linear density under the conditions of fibers formation. For the fibers based on polymer mixtures, the presence of oxidized fragments in the secondary PET limited the compatibility of the two polymers which resulted in deteriorated tensile properties. The linear density (4–16 dtex), tensile strength (30–50 cN/tex) and elongation at break (20–60 %) of the PET fibers obtained were close to these for the industrially produced polymer fibers. The values of the average diameter of the fibers formed and oriented under laboratory conditions allows classifying them between the fine and the coarse textile fibers which makes them suitable for the textile industry.     

水稻病虫害绿色防控与统防统治融合技术模式示范

2017—2018年,在同安镇粮食产能区示范推广水稻病虫害绿色防控与统防统治融合技术模式,取得了显著成效。融合技术示范区比常规区减少用药2~3次,用药量减少37.6%,防治成本降低400元/hm^2;水稻产量增加12.8%,收益增加2 835元/hm^2。     

我国麻类标准现状与分析

介绍了我国麻类标准的现状。通过分析,指出了存在的问题,主要表现在标准体系不完善、标准更新不及时,协调性差及贯彻执行不力等。提出了我国麻类标准应采取的对策。     

海南百香果病虫害种类调查鉴定及其发生危害

百香果是海南省的新兴产业,也是我国多个省区扶贫攻坚的重要产业。病虫害是影响百香果产业的重要因素,随着海南百香果种植面积越来越大,病虫害对百香果产业的不利影响越来越凸显。由于缺乏百香果病虫害种类调查鉴定的基础性研究,许多种植户对田间发生的病虫害种类识别不足,从而影响了百香果病虫害的防控效果。为了摸清海南百香果种植区的病虫害种类,于2019—2021年对海南省儋州市、乐东县、屯昌县、文昌市、三亚市、东方市、保亭县、白沙县、海口市等百香果种植区的病虫害进行了系统调查与鉴定,并对其发生危害特点进行了研究。鉴定发现海南百香果种植区的病害有11种,分别是病毒病、茎基腐病、炭疽病、疮痂病、疫病、灰霉病、果腐病、褐斑病、烟煤病、藻斑病和缺镁。重要病害为病毒病和茎基腐病,危害程度分别为4级和3级,炭疽病和疮痂病危害也较重,危害程度均为2级,其他病害危害较轻。害虫有28种,分别是黄胸蓟马、茶黄蓟马、红带蓟马、美洲棘蓟马、普通大蓟马、咖啡木蠹蛾、美洲斑潜蝇、橘小实蝇、斜纹夜蛾、双线盗毒蛾、绿丽刺蛾、白带锯蛱蝶、烟粉虱、温室白粉虱、柑橘粉蚧、木槿曼粉蚧、藤壶蜡蚧、茶角盲蝽、樟颈曼盲蝽、稻绿蝽、中稻缘蝽、茶小绿叶蝉、丽球瓢蜡蝉、绿鳞象甲、眼斑芫菁、白条豆芫菁、甘薯梳龟甲和朱砂叶螨。重要害虫为黄胸蓟马和咖啡木蠹蛾,危害程度均为3级,茶黄蓟马和美洲斑潜蝇的危害也较重,危害程度均为2级,其他害虫危害较轻。软体动物3种,分别是灰巴蜗牛、同型巴蜗牛和一种尚未鉴定的蛞蝓。本研究明确了海南百香果种植区病虫害具体种类,新发现百香果病害1种和害虫24种,为海南百香果病虫害的精准防控提供技术支撑。     

Effects of Organic and Chemical Fertilizers and Arbuscular Mycorrhizal Inoculation on Growth and Quality of Cucumber and Lettuce

Summary

Arbuscular mycorrhizae were inoculated into phosphorus-deficient soil fertilized with either organic or chemical fertilizer with cucumber (Cucumis sativus L.) as the first crop and lettuce (Lactu-ca sativa L.) as the second crop but without additional fertilization and AM inoculation. AM increased dry matter and fruit yield of cucumber significantly in the unfertilized, organic-fertilized and P-deficient plants compared with the fully chemical-fertilized plants. AM inoculation increased the available phosphorus in plant and soil by around 30% for all treatments except for those chemically-fertilized. The rate of AM infection did not differ significantly among the fertilization treatments, but the infection intensity was higher in unfertilized, organic-fertilized and phosphorus-deficient treatments than chemical-fertilized treatment. The residual effects of AM-inoculated to cucumber were evident for lettuce in all pre-treatments that were unfertilized and un-inoculated for the second cropping. Without P-fertilization, neither crop could grow optimally even when the soil was inoculated with AM, suggesting that AM could not serve as a substitute for phosphorus fertilizer. However, the other beneficial effects of AM on crop growth and yield could not be fulfilled with phosphorus fertilizer.     

春季氮肥和多效唑调控对小麦生育和产量的影响

为明确春季调控措施对冬小麦生长发育和籽粒产量的影响,以冬小麦品种石新828为材料进行田间试验,4个处理分别为:起身期追全部氮肥(除基肥外,下同)并叶面喷多效唑(N1);起身期追2/3氮肥并喷多效唑+拔节期追1/3氮肥(N2);起身期追1/3氮肥+拔节期追2/3氮肥(N3);拔节期追全部氮肥(N4)。生育期间测定群体和个体生育特性,成熟期调查产量性状。结果表明,N1和N2处理小麦拔节期的总茎数、叶面积指数(LAI)和干物质积累量均显著高于N4和N3处理。孕穗期N4和N3处理小麦的总茎数、LAI和干物质积累量显著高于N1和N2处理。开花到成熟期各处理的总茎数、LAI和干物质积累量差异均不显著。孕穗期前,不同处理的株高差异不显著,孕穗期后,N4处理的株高最高,且显著高于N1处理。各处理基部节间直径和中上部节间长的差异不显著,N4处理基部第一节间长度显著大于其他处理。随追氮时期前移或前期施氮量增多,不孕小穗数减少,结实小穗和穗粒数增加,N1比N4处理不孕小穗数显著减少,结实小穗和穗粒数显著增多。N1处理小麦成熟期的千粒重最高,且显著高于N4处理。N1处理的籽粒产量最高,且显著高于N3和N4处理。起身期追氮配合多效唑调控,可以获得比拔节期追氮更高的穗粒数和千粒重,从而获得更高的产量。     

Interactive Effects of Sodium and Potassium on the Growth and Photosynthesis of Spinach and Komatsuna

Abstract

Two cultivars of spinach and one cultivar of komatsuna were sand cultured using a nutrient solution with Na and K in various combinations. The growth (fresh weight of shoot) of spinach cv. Atlas was significantly increased when 1.4 mM KC1 of the 7 m M KO was replaced with 1.4 mM NaCl, although the growth was reduced when more KC1 was replaced with NaCl. In another spinach cv. All Right, however, NaCl substituting for 20% of KC1 showed no significant effects. In komatsuna, Na used in place of K at any ratio reduced the growth. The growth of spinach cv. Atlas was increased by applying 20 mM NaCl, irrespective of K dose (480 - 2400 mg K₂O per 1/2000 a Wagner pot). The growth of spinach cv. All Right was also increased by 20 mM NaCl when K was at a deficient level (480 - 960 mg K20 per pot), but was not when K was at: an excessive level (1920 - 2400 mg K₂O per pot). In komatsuna, 20 mM NaCl reduced the growth. In spinach, Na prevented the decrease of the photosynthetic rate and stomatal conductance caused by K deficiency.     

苯醚甲环唑和嘧菌酯在水稻中的残留消解动态及残留分析

本文建立了气质联用仪测定稻田环境中苯醚甲环唑和嘧菌酯的残留分析方法,对苯醚甲环唑和嘧菌酯在水稻、土壤和田水中的消解动态和残留规律进行了研究。苯醚甲环唑和嘧菌酯在糙米、稻壳、植株、土壤和田水中的最低检测浓度均为0.20 mg/kg,最小检出量为0.2 ng,在不同样品中的平均加标回收率为80.8%~109.5%,相对标准偏差在1.7%~19.7%之间。田间试验结果表明,苯醚甲环唑和嘧菌酯在水稻植株和田水中的残留消解动态规律均符合一级动力学反应模型,苯醚甲环唑在水稻植株和田水中的残留消解半衰期分别为6.3~11.6 d和1.4~11.6 d;嘧菌酯在水稻植株和田水中的残留消解半衰期分别为3.6~8.7 d和2.9~23.1 d。以推荐剂量600 g/hm2和1.5倍推荐剂量900 g/hm2,最多施药3次,距最后一次施药15 d时,苯醚甲环唑和嘧菌酯在糙米中的最高残留量分别为0.461 mg/kg和0.634 mg/kg,低于我国国家标准《食品中农药最大残留限量》(GB2763-2014)中规定的糙米中苯醚甲环唑最大残留限量0.5 mg/kg和欧盟、美国规定的糙米中嘧菌酯最大残留限量5.0 mg/kg。     

白砂糖干燥与冷却机理及影响

砂糖的含水量、装包温度和仓储条件对其贮存保质具有重要影响。本文从白砂糖的含水分特性、干燥机理和生产过程环节等对白砂糖干燥与冷却的影响进行深入分析。由于结晶过程的包裹现象,砂糖含水分可分为表面和内部水分,白砂糖干燥过程只能去除前者。生产过程中煮糖、分蜜操作对内部水分含量有影响。贮存过程的内部水分的扩散是砂糖降质的根本原因,而装包温度和贮存条件是影响内部水分扩散的外在条件。     

浙江省水稻产业科技发展成就及对策建议

以对应水稻全产业链构建水稻科技创新链的视角,分析了浙江省水稻产业科技发展的成就,重点分析了水稻育种、生产、加工和销售等环节的科技发展成就,探讨并提出了推进浙江省水稻产业科技发展的对策,以期为相关政府职能部门决策以及提升浙江省水稻科技创新能力提供参考。     

甘蔗病虫害防治技术及高效低毒农药应用

对严重影响甘蔗生产的8种甘蔗主要害虫和5种甘蔗常见流行性病害的发生危害特点进行了探讨和综述。依据甘蔗病虫害的危害特点,提出以农业防治方法为基础,物理防治灯光诱杀、生物防治为辅,减少虫源病源,统一化防为重点和抓好关键时期科学用药的综合防治措施,从而达到高效、快速、持续、有效控制甘蔗病虫害的发生危害,确保甘蔗生产持续稳定健康发展。     

播期、收获期对玉米生长发育及冠层性状的调控

采用均匀试验设计,研究6个播期配合6个收获期对郑单958和伟科702生长发育、株型结构和产量性状的影响,通过播期、收获期调控实现高产。结果表明,冀中地区6月12日前播种,玉米抽雄和吐丝持续时间更为集中,播期每推迟3 d,抽雄和吐丝日期后推1 d;继续推迟播期,抽雄和吐丝日期后推4~5 d。2014年6月12日播种处理吐丝期冠层温度最高,不利于玉米授粉;6月15日后播种穗位叶SPAD值降低,尤其是生育后期伟科702叶片SPAD值降低幅度较大。播期对株高、穗位高和基部茎粗影响较大,播期与收获期对产量及其构成影响均显著,穗粒数随播期推迟而降低,千粒重随生育期延长而提高。经回归分析得出,夏玉米每提早播种1 d,产量平均增加98.4 kg/hm2;每推迟收获1 d,平均增产103.3 kg/hm2。郑单958获得较高产量的播期、收获期最佳组合为6月6日至6月12日播种,10月4日至10日收获。     

热区蔬菜质量安全分析与评价

对影响我国热区主要蔬菜产前、产中、产后的质量安全相关因素与现状进行调研,获取基础数据与有关信息。对比分析国内不同生产区质量安全存在的差异与差距,研究我国热区蔬菜从生产至市场各个环节的质量安全评价方法,提出建立我国热区蔬菜质量安全评价体系方案。     

源库限制对寒地玉米产量及品质的影响

本试验采用4个品种(四单19、本玉9号、DH808、DH3149),2种密度(52500株/hm2、75000株/hm2),并在吐丝期分别进行减源限库处理,研究源库限制对玉米生长发育和产量品质的影响。结果表明:减源处理降低了单株叶面积,也降低了单株干物重。限库处理因库容减少,使得干物质略有增加,但不同品种对源库处理反应不一致。限库处理导致玉米子粒蛋白质含量明显增加,减源处理基本不变或略有增加;减源限库处理导致平展型玉米子粒的脂肪含量增加,而紧凑型品种保持不变或略有降低;减源处理导致淀粉含量的增加,而限库处理的影响相反,导致淀粉含量减少。     

湖南省主要抗病虫品种选育和利用现状与问题

全面分析了湖南省主要病虫灾害的现状、发生趋势,认为随着水稻种植结构和栽培技术的变革以及水稻新品种的应用,病虫害发生种类及其危害性的变化,将使病虫害问题更加突出。在对抗性品种在农业生产中的实际效用进行分析后,提出了抗病虫品种选育和利用中存在的问题及改进意见。     

种子加工、检验理论与技术现状及思考

种子加工及检验是种子向市场流通的关键，是商业化育种中赋予种子商品属性不可或缺的环节。种子加工、检验理论与技术的研究是完善种业产业链、实现规模化商业育种、夯实“育繁推一体化”种业科学的重要一环。中国的种业科学技术体系正在形成与完善之中，受制于行业发展水平，种子加工及检验理论与技术相对薄弱。本文回顾了种子加工及检验理论与技术研究发展历程，提出了完善中国种业科学发展的策略与建议。围绕种业发展的需要，在做好品种优质化繁育的基础上，分析种子加工及检验理论与技术的新方向和新需求，加强种业应用性研究，建立先进的种子质量检验体系，研制适合现代种业发展需求的种子加工设备，打造种子加工产业标准化生产体系，完善种业科学技术学科建设，促进种业产业持续健康发展。     

浅议茶旅融合发展的意义与途径

茶旅融合与互动发展是茶产业及旅游产业发展的内在需求,也是实施乡村振兴战略的重要抓手,对于破解茶产业利润增长瓶颈具有重要意义。本文浅析茶旅融合互动发展对产业的促进作用,结合浙江省茶旅产业的实践案例和模式提出推进茶旅融合发展的建议与途径,以期为茶产业与旅游产业融合发展带来新思路。     

不同原料及配方添加锌、硒对大球盖菇生长及产量的影响

[目的]研究不同栽培料配方添加锌、硒微量元素对大球盖菇生长及产量的影响.[方法]设置9个栽培料配方处理,并添加锌、硒微量元素,测定各处理大球盖菇菌丝长势、出菇时间、产量、生物转化率等指标.[结果]富硒香菇菌渣30％+玉米芯70％配方,熟料栽培产量35574.32 kg/hm2,产量排名第1位,生物转化率56.9％;富硒...     

Growth and photosynthesis of tall and short cultivars of white clover with tall and short grasses

A comparison was made of canopy structure, photosynthesis and dry weight production, during growth periods in spring and summer, of a large-leaved and a small-leaved cultivar of white clover (Blanca and S184), grown in mixtures with perennial ryegrass or tall fescue. Both clovers had leaves in the topmost, best-lit layer of the canopies, even when sward surface height reached 40 cm in early June. Except early in the spring growth period, both clovers had a greater proportion of their leaf area near the top of the canopy than did their companion grass. Both clovers had a greater relative growth rate than the grass, increasing their percentage of the total crop dry weight during both spring and summer growth periods. Differences between clover cultivars were relatively minor and did not affect their dry weight in either measurement period. During the first growth period there was more clover dry weight with tall fescue than with ryegrass. There were no effects of clover cultivar on grass dry weights.