甜菜穴棚式地膜覆盖栽培技术初探

甜菜地膜覆盖栽培有明显的增产效果,已被各地生产实践所证实。但是由于覆膜后,膜内温度高,带来高温烤苗的问题。据测当膜下地表温度在43℃以上,甜菜只要接触地膜3～5小时,即可被烤伤。吉林省白城地区4～5月份的气温变幅大,覆膜后又加大了地表温度差值。地膜覆盖膜下地表平均温度分别是:4月下旬最高42.6℃,最低-2.3℃,5月上旬最高57.8℃,最低1.9℃。覆膜地表平均温差45℃以上,超出了甜菜生长对温度要求的极限。如果膜下没有穴间,甜菜出苗后就接触地膜,极易出现冻害和高温烤苗,对保苗极为不利,但是膜下空间大,甜菜     

遮荫对夏暑乌龙茶品质的影响及其机理研究报告(续)——茶园遮荫生态效应研究

2.1.2.1地表温度 表3表明:遮荫明显降低了地表日最高温度.与对照同比,60%、45%和30%遮荫度3个处理的平均日最高温度,6月份分别下降了5.85℃、5.16℃、4.56℃,7月份下降了13.44℃、12.80℃和11.43℃,8月份下降了7.03℃、6.18℃和5.34℃,降幅7月份＞8月份＞6月份,60%＞45%＞30%.这一结果与树冠层的日最高温度变化趋势相一致,但其温度值小于树冠层,而降温幅度却大于树冠层.     

温度和补充营养对茶卷叶蛾长体茧蜂成蜂寿命的影响

在实验室控温条件下,研究了不同温度和营养对长体茧蜂寿命的影响.结果表明:长体茧蜂寿命长短依次为18℃＞21℃＞24C＞27℃＞30℃,在18～30℃范围内,随着温度升高,长体茧蜂的寿命显著缩短;雄蜂寿命明显短于雌蜂.补充营养对雌蜂寿命的影响大于对雄蜂寿命的影响,在18～27℃条件下,补充营养显著提高了雌蜂的寿命,在30℃条件下,差异不显著.     

氨基寡糖素和钾营养调节剂对烟草普通花叶病毒病的防治效果

为探索防治烟草普通花叶病的农艺措施,采用田间试验,研究了氨基寡糖素和钾营养调节剂配施防治烟草普通花叶病毒病的效果及对烟叶产量、质量的影响。结果表明,氨基寡糖素和钾营养调节剂配合施用能有效降低烟株普通花叶病毒病的发病率和病情指数,平均防效达到56.31%,两者配施还明显提高了烟叶的产量、产值、均价、上等烟比例等经济指标,分别较对照(喷施清水)提高27.60%、44.26%、13.02%、42.48%,并能提高烟叶的外观质量和评吸质量。     

遮荫对夏暑乌龙茶品质的影响及其机理研究报告--茶园遮荫生态效应研究

夏署季黄 茶园遮荫试验结果表明,遮荫显著改善了夏署季茶园的水热条件,能够避免连续高温干旱天气对茶树造成的热害和旱害,降低杂草的生长.与不遮荫的对照处理相比,5～8月份30%、45%和60%遮荫度3个处理树冠层的白昼平均温度、日极端最高温度及温度日较差分别下降了1.47℃～4.42℃、3.95℃～7.26℃和3.33℃～8.44℃,白昼平均湿度、日极端最低湿度分别增加了4.31%～12.31%和3.27%～12.62%,湿度日较差减少了3.58%～12.94%;地表日极端最高温度及日较差分别下降了4.56℃～13.44℃和4.53℃～12.80℃;茶园20cm内土层的温度明显下降,含水率明显提高;茶园持续高温干热天数明显缩短;白天温、湿度极端值出现时间较迟、历时较短.它们与对照的差异均达到极显著或显著水平,且效果(增幅或降幅)随着遮荫梯度的增大和光照强度的增强而加大.     

幼龄茶果园套种竹豆对生态环境,改土培肥和茶果树生长的影响

幼龄茶果园套种竹豆生长快，生物量大，鲜草产量高，为幼龄茶果园提供大量优质有机肥源。由于竹豆根系发达，生长旺盛，增加地表覆盖，截留雨水提高土壤含水量，降低６－８月地表温度，增加园内相对湿度，改善生态环境，改良土壤，提高土壤肥力和新植茶果定植成活率，促进茶果树生长，是一肥多用肥新品种。     

闽东侵蚀劣地幼龄茶园套种绿肥的生态效应

侵蚀劣地幼龄茶园套种5种绿愿在高温季节午间14时平均降低地表温7℃降低20cm土层温度2．09℃，缩小地表和20cm土层温度日间变幅；平均提高土壤含水量2％、提高土壤速效养分含量的效果为：碱解N16．62mg/kg、速效P9．69mg/kg、速效K8．00mg/kg，起到恢复和提高茶园地力作用。     

花生壳常压酸水解制备乙酰丙酸

以花生壳作为生物质水解原料,各种无机酸和有机酸作为水解用酸催化剂,研究水解过程中葡萄糖和乙酰丙酸产率。结果表明:对于无机酸来说,温度越高,原料的质量损失越大,在220℃时可达到80%左右;葡萄糖产率和乙酰丙酸产率均随着温度提高而提高,葡萄糖产率最高可达到75%以上(180℃),乙酰丙酸产率最高可达到20%以上(220℃);硫酸和盐酸的效果明显好于磷酸和硝酸。对于有机酸来说,温度对原料的质量损失影响不大,徘徊在40%左右;温度越高,葡萄糖产率受到抑制,乙酰丙酸相对转化率较高,草酸水解时可达到25%以上(220℃);草酸的效果明显好于乙酸和柠檬酸。     

生长调节剂对红掌抗性的影响

红掌（Anthurium andraeanum）属天南星科花烛属植物，是当前国际流行的高档花卉。原产地中海一带，性喜温湿，生长适宜温度为18—32℃，13℃以下易出现寒害，温度太高也易导致生长不良，花叶畸形，影响观赏价值。     

世界西番莲研究近况：Ⅳ营养与施肥

西番莲虽属果树类,但其习性却更象蔬菜瓜类攀缘作物,因此营养管理有别于其它果树.对西番莲营养水平影响的因子主要有:温度(包括土温)、土壤水份、光照及土壤中有效养份的浓度.植株的营养诊断是实行科学施肥的首要条件,为此,需要了解西番莲的营养标准.如果某种养份严重低于其正常的范围,植株就会出现缺素症状,而影响产量.肥料施用时不仅要考虑施用肥料的种类,且要考虑施用量以及施用时间,这样才能使养份管理科学化.     

不同地区橡胶树红根病菌的生物学特性及室内毒力测定

橡胶树红根病是我国分布最广、危害最重的橡胶树根部病害。为明确我国海南和云南地区橡胶红根病菌的生物学特性及对杀菌剂的敏感性,采用十字交叉法研究了不同培养条件对病菌菌丝生长的影响,并测定了10种不同杀菌剂对病菌的抑制作用。结果表明,病原菌在玉米+橡胶根的培养基上生长最快,对温度、pH等适应范围广,温度在13~31 ℃,pH在3~10均能生长,最适生长温度为28 ℃,多数菌株最佳pH为7~9,且能利用多种碳氮源;不同的碳源中,果糖、半乳糖、麦芽糖、葡萄糖和甘露糖较适合该菌的生长;在供试氮源中,菌丝在酪氨酸、牛肉浸膏的基础培养基上生长最快,在色氨酸和尿素的基础培养基上生长最慢;光照对病菌有抑制作用,黑暗有利于菌丝生长;菌丝的致死温度为47 ℃,10 min。不同地区的病原菌株间药剂敏感性存在一定差异,戊唑醇抑菌效果最好,其EC₅₀为0.0312 μg/mL,其次为嘧菌酯、十三吗啉、咪鲜胺和腈菌唑,EC₅₀分别为0.5581、0.6759、1.3763和1.5603 μg/mL。     

温度和供氮形态对龙眼吸收氮素动力学的影响

研究龙眼幼苗在不同温度（10、15、20、25、30、35℃）和不同氮营养（硝态氮、3/4硝态氮+1/4铵态氮、1/2硝态氮+1/2铵态氮、1/4硝态氮+3/4铵态氮、铵态氮）供应条件下吸收氮素的动力学特征,比较龙眼吸氮能力变化,并探讨龙眼对氮形态的偏好性,为龙眼不同季节（物候期）选择适用氮肥形态提供依据。结果显示,温度和供氮形态对龙眼吸氮能力有显著影响（P<0.05）。在中低温度（10~25℃）等量供应硝态氮和铵态氮条件下,龙眼根系吸收氮素（硝态氮和铵态氮之和）的最大吸收速率（I_max）最高或较高,而亲和力（Am）和离子吸收补偿点（C_min）则随温度和氮形态变化不大,故此时龙眼吸氮能力强。在高温（30℃）且仅供应铵态氮时,根系具有最高I_max和A_m,同时C_min最低,最有利于龙眼吸氮。在极端高温（35℃）时将铵态氮和硝态氮以3∶1的比例配合供应,则I_max最高,A_m较高且C_min较低,有利龙眼对氮素的吸收。另外,等量硝态氮和铵态氮共存条件下,龙眼在低温（10~15℃）时吸收铵态氮的I_max更高、A_m更强而且C_min更低,明显偏好铵态氮;在中高温（20~35℃）时吸收硝态氮的I_max更高,但A_m更弱且C_min更高,对氮形态的偏好性不明显。对照华南龙眼生长物候期,建议在龙眼秋梢生长期施用铵态氮为主、硝态氮为辅;在花前至小果期可以1∶1的比例施用硝态氮和铵态氮;在果实膨大期,可全部施用铵态氮或以3∶1的比例施入铵态氮和硝态氮。     

Within-Canopy Distribution of Stenoma catenifer (Lepidoptera: Elachistidae) Infestation in Avocado Orchards

Native to the neotropics, the avocado seed moth Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) is a specialist pest of the family Lauraceae and considered one of the most important pests of avocados worldwide. However, little is known regarding its spatial distribution within a single tree. Therefore, we designed a study to evaluate the effects of canopy height and aspect (i.e., side of the tree) on fruit infestation by S. catenifer larvae in avocados. The study was conducted in three commercial organic avocado orchards located in São Paulo, Brazil. At each orchard, 40 fruit from 30 random trees were sampled weekly from October 2017 through February 2018, evaluating the number of fruits infested by S. catenifer larvae at three tree heights (bottom, middle, and top). In addition, fruits on the ground were also sampled. We also evaluated the effect of the side of the tree where the fruits were collected, i.e., whether they were on the side facing the east (sunrise) or the west (sunset). Within the avocado canopy, the level of fruit infestation by S. catenifer larvae was significantly higher at the top of the trees than in the middle and bottom. Fruit on the ground had lower levels of infestation than those on the tree canopy. The level of fruit infestation was also higher on the side of avocado trees facing the east (sunrise). Understanding the within-tree distribution of S. catenifer will help to better target monitoring and control activities against this pest in avocados.     

超声-微波协同提取百香果皮果胶的工艺研究

以果胶得率为分析指标,采用超声-微波协同提取百香果干果皮果胶,利用响应面分析法优化其工艺条件。结果表明,百香果皮果胶超声-微波协同提取的最佳工艺参数为：液料比30 mL/g,pH 2.0,温度50 ℃,水浴60 min,超声功率50 W、微波功率600 W、超声-微波时间8.0 min,在此条件下,果胶得率可达(12.14±0.06)%。超声-微波协同法的提取效果与单独水提、超声、微波法的相比,得率分别提高了47.33%、34.74%和23.50%,3种提取方法的酯化度均≥50%,其说明百香果皮果胶属于高甲氧基果胶。扫描电镜结果显示,百香果皮细胞壁在超声-微波协同作用下破碎更为彻底,利于果胶溶出。     

Effects of irrigation deprivation and ground cover (Trifolium repens) in the tree row on brown rot incidence in peach

Brown rot can lead to considerable fruit losses in peach orchards and cultural practices likely to contend this major disease have to be promoted. In order to limit peach brown rot incidence in a three-year-old mid-season maturing peach orchard of the cultivar ’Ruby Bright’, four combinations of irrigation and soil management treatments were assessed: conventional (Conv) irrigation (I) and soil management (S) (ConvI+ConvS); modified (Mod) irrigation and soil management (ModI+ConvS); conventional irrigation and modified soil management (ConvI+ModS); and modified irrigation and soil management (ModI+ModS). Conventional irrigation and soil management in the tree row consisted of irrigation scheduling using tensiometer readings and herbicide use, respectively. Modified irrigation and soil management in the tree row consisted of water deprivation during stage III of fruit development and ground cover with white clover, respectively. For four consecutive years (2010–2013), in the conditions of the Middle Rhone Valley in France, the lowest and highest brown rot incidence were detected under (ModI+ModS) and (ConvI+ConvS), respectively, whereas brown rot incidence under (ModI+ConvS) and (ConvI+ModS) was intermediate. This lower brown rot incidence under the modified treatments occurred from one to two weeks before fruit maturity and was still observed for several days in post-harvest storage. Ground cover with white clover was shown to limit water availability in the soil after heavy rainfall compared to bare soil, probably limiting peach growth variations, well-known as a possible source of detrimental microcracks at the fruit surface. This suggests that under our conditions appropriate cultural practices, water deprivation and a clover crop cover in the tree row possibly decrease peach disease sensitivity, which might lead to the reduced use of pesticide sprays to control brown rot in the orchard.     

河口植胶区橡胶树根病发生特点及综合治理分析

通过对河口植胶区先后3次较全面详细的橡胶树根病普查资料及2012年割胶林根病区普查资料统计分析得出：河口植胶区50多年来橡胶树根病发生呈现危害重、受害面广、根病种类不断增加及病害整体呈不断扩展蔓延上升态势等特点;充分暴露出复垦胶园病区多,橡胶树根病更加突出,新植幼林第2年,甚至第1年就出现根病危害,第7年根病累计发病率已达到3.1%。并从橡胶树根病治理难度大、成本高、见效慢、效果差,治理工作难以坚持,以及农垦改革后各单位根病调查和治理工作基本停止或得不到重视等方面阐明目前生产上橡胶树根病综合治理存在的现状和问题。提出进一步完善体制和经营机制,建立健全橡胶树根病治理制度;加强宣传教育,提高管理人员对橡胶树根病危害性认识;增加橡胶树根病综合治理和胶林复垦的投入;加强橡胶树根病综合治理新技术研究与推广应用等建议和对策,以便真正把橡胶树根病治理落到实处,更快更好促进我国天然橡胶产业可持续、健康、安全发展。     

橡胶树炭疽菌HCkHNQZ1736 β-TUB2基因对多菌灵的抗性相关性分析

天然橡胶是四大工业原料中唯一的可再生资源,由炭疽病菌侵染引起的橡胶树炭疽病是当前我国橡胶生产上最为严重的两大叶部病害之一。本研究以分离自云南保山的喀斯特炭疽病菌MeCkYN1705为对照,对海南新发炭疽病菌喀斯特炭疽菌HCkHNQZ1736进行抗药性评价。结果表明,菌株HCkHNQZ1736对苯并咪唑类杀菌剂多菌灵表现出高抗药性,EC₅₀达1107.2654 µg/mL,而MeCkYN1705的EC₅₀仅为0.0554 µg/mL。克隆了菌株HCkHNQZ1736的tub2基因,序列分析发现其所编码的第198个氨基酸位点由谷氨酸（Glu-E）突变为丙氨酸（Ala-A）,推测该氨基酸位点突变是导致该菌株产生多菌灵抗性的原因。此外生物学特性测定发现,该菌株最适生长温度为28 ℃,致死温度为35 ℃;最适生长pH为6;光暗交替利于菌落生长;果胶、蛋白胨分别为最适碳源和氮源。     

橡胶树臭根病菌的鉴定及其生物学特性研究

利用海南省橡胶树臭根病病株上采集的病根样本,采用菌索组织分离法获得菌落后,进行子实体诱导产生分生孢子,再经单孢分离纯化获得菌株HNDZ001,通过柯赫氏法则验证、形态学特征观察及分子生物学技术对该菌株进行鉴定,确定菌株HNDZ001为引起橡胶树臭根病的匐灿球赤壳菌(Sphaerostilbe repens Berk.&Br.)。生物学特性测定结果表明,菌株HNDZ001在PDA培养基上菌落近圆形,表面黄白色,致密,背面呈深褐色至浅黄色,后期会产生黄褐色菌索和孢梗束;该菌菌丝生长的适宜条件为温度25~34℃、p H 7~9,最适生长条件是温度28℃、pH值为8、甘露醇为碳源、牛肉浸膏为氮源、完全黑暗,且在黄瓜汁培养基上菌丝生长最好。     

Effect of cultural practices and fungicides on Phytophthora fruit rot of watermelon in the Carolinas

Phytophthora fruit rot of watermelon, caused by Phytophthora capsici, is an important and emerging disease in Southeastern U.S.A. The effects of two cultural practices (raised bare ground and raised plastic mulched beds) used for growing watermelon and different fungicide treatments on development of Phytophthora fruit rot were evaluated. The experiments were conducted over three years (2005-2008) at research stations in North Carolina and South Carolina, U.S.A. Fungicides were applied at weekly intervals on the diploid cv. Mickey Lee for an average of five applications. Fruit rot incidence was recorded at the end of each experiment. Fruit rot incidence in the non-treated plots was 66% across two states and six trials. Overall, the levels of fruit rot on the raised bare ground and raised plastic mulched beds were not significantly different. Based on percent disease reduction relative to the non-treated check plots, the fungicide Captan was the most effective across years and locations (range = 23-70%, mean = 57%), followed by mandipropamid (25-65%, mean = 50%), fluopicolide (24-65%, mean = 43%) and cyazofamid (0-48%, mean = 31%). Mefenoxam, the current standard treatment reduced fruit rot by 8-28% (mean = 18%). The addition of copper hydroxide to the spray mix did not significantly enhance effectiveness of Captan or mandipropamid. The variability in fungicide efficacy observed in these experiments across locations and years demonstrates the importance of environmental conditions in disease development and management. Even when the most effective fungicides are used, heavy losses may occur when conditions are highly favorable for disease development. Ultimately, effective control of Phytophthora fruit rot of watermelon will require an integrated management strategy that includes well-drained fields, water management and crop rotation in addition to fungicides.     

西番莲水通道蛋白PePIP2基因克隆及表达分析

西番莲作为新兴的热带果树，在热带农业中具有非常重要的作用，然而干旱、高温等非生物胁迫严重影响其正常生长发育。相关研究表明水通道蛋白(AQP)能够提高植物的抗逆性，本研究以西番莲‘台农’(Passiflora edulia Sims)为实验材料，利用西番莲的基因组数据，通过同源克隆法从西番莲中克隆得到了一个水通道蛋白基因PePIP2，其开放阅读框(open reading frame,ORF)为861 bp，编码286个氨基酸。对其进行生物信息学分析，其分子式为C₁₄₁₇H₂₁₅₆N₃₆₀O₃₇₃S₈，预测分子量为30 459.37 Da，等电点为8.84，亚细胞定位于细胞膜上。启动子区域分析显示其含有参与胁迫应答的顺式作用元件。对其进行干旱、高盐、低温、高温胁迫下的表达分析，结果表明：PePIP2能够受到干旱、高温和低温胁迫的诱导表达，其中在土壤含水量为50%，在45℃高温处理4 h和0℃低温处理48 h，其表达量最高。在烟草中进行瞬时表达，在不同时间的干旱胁迫处理下，PePI...