不同寄主植物对柑橘木虱发育和繁殖的影响

【目的】研究柑橘木虱Diaphorina citri Kuwayama在柚、酸橘、黄皮、九里香、砂糖橘5种代表性芸香科寄主植物上的发育、存活和繁殖情况,为柑橘木虱及黄龙病的可持续防控提供参考。【方法】利用种群生命表的方法,分析了柑橘木虱在5种不同寄主植物上的发育历期、存活率、成虫寿命、性比及产卵量等数据。【结果】柑橘木虱卵、1龄若虫以及整个若虫的发育历期受寄主植物的影响较为明显,在26℃条件下在柚子植物上柑橘木虱若虫的存活率最高(58.10%),在黄皮上最低(46.04%),两者差异显著。寄主植物影响柑橘木虱成虫寿命,在柚子上柑橘木虱成虫的寿命显著长于黄皮上的寿命。黄皮上的柑橘木虱的单雌产卵量(298粒/雌)显著低于其他4种寄主植物。柑橘木虱在九里香上的内禀增长率(rm)最高(0.133 7)、酸橘上最低(0.129 8);而净增值率(R0)在砂糖橘上最高(187.74)、黄皮上最低(145.27)。【结论】在5种寄主植物中,除黄龙病隐症寄主九里香之外,显症寄主中砂糖橘是柑橘木虱的最适寄主。     

不同种类寄主对柑橘黄龙病菌侵染能力及虫媒适应性的影响

柑橘木虱Diaphorina citri是柑橘黄龙病菌“Candidatus Liberibacter asiaticus”的主要媒介昆虫，探明不同植物种类寄主对柑橘黄龙病菌侵染能力及柑橘木虱适应性的影响，在设计黄龙病防控策略及寄主抗性研究中具有参考价值。本文选取蕉柑Citrus reticulata、蜜柚Citrus grandis、黄皮Clausena lansium和九里香Murraya exotica为研究材料，对比其田间植株黄龙病发病率和柑橘木虱数量及带菌情况，并在实验室条件下比较柑橘木虱对不同寄主的适应性（包括发育历期、存活率、携菌能力和传菌能力）。结果发现：（1）田间蕉柑和蜜柚的感染率最高，分别为47%和37%；而黄皮和九里香的带菌率较低，分别为18%和4%，且菌浓度均较轻微；（2）田间九里香上柑橘木虱卵、若虫及成虫数量均最多，蕉柑和黄皮其次，蜜柚最少，但蕉柑和蜜柚上柑橘木虱的携菌率和携菌量最高；（3）4种寄主上柑橘木虱卵和1~3龄若虫的发育历期没有显著性差异，柑橘木虱4龄、5龄若虫和总若虫历期在九里香上最短，而在蜜柚上最长；4种寄主上4龄、5龄若虫存活率没有显著性差异，但蜜柚上木虱卵的孵化率、1~3龄及总若虫存活率最低。（4）蕉柑和蜜柚上带菌木虱的携菌能力及传菌能力最高，其次为黄皮，九里香最低。该研究证明了除了寄主植物本身抗病性差异外，虫媒对寄主植物的适应性差异也是造成田间黄龙病发病差异的重要因素。     

亚洲柑桔木虱若虫在寄主上的转移和扩散研究

黄龙病是世界柑桔产业的一种毁灭性病害，亚洲柑桔木虱Diaphorina citri Kuwayama为黄龙病亚洲种和美洲种的媒介昆虫，其成虫和高龄若虫都能传病。本文研究亚洲柑桔木虱若虫在感染黄龙病及健康寄主上的转移和扩散规律，发现3龄及3龄以上若虫在柑桔植株垂直和水平位置的嫩梢之间转移现象十分明显，但在黄龙病植株上转移速度较健康植株慢，且嫩梢间的转移速度受虫密度的影响，密度越高转移速度越快。在有选择的条件下，水平位置转移过程中若虫更趋向黄龙病植株。此外，在健康寄主上的木虱若虫有明显向植株下部转移的现象，向下部转移的若虫个体数显著高于黄龙病寄主。本文明确了木虱若虫的扩散规律和寄主感染黄龙病对其转移和扩散产生的影响，为柑桔木虱和黄龙病防治提供参考。     

亚洲柑橘木虱成虫和5龄若虫在感染黄龙病的柑橘上的取食行为及获菌效率比较

【目的】亚洲柑橘木虱Diaphorina citri是柑橘的毁灭性病害——黄龙病亚洲种‘Candidatus Liberibacter asiaticus’(‘C las’)的主要传播媒介。本研究的目的是明确木虱成虫和5龄若虫的取食行为、获菌效率是否有差异,以及寄主感染黄龙病是否对5龄若虫取食产生影响。【方法】利用直流型刺吸电位仪(DC-EPG Giga-4)记录柑橘木虱成虫和5龄若虫在携带黄龙病的酸橘Citrus reticulata cv.Sunki嫩梢上10 h的取食行为,用qPCR单头检测其获得黄龙病病原菌的效率,并比较5龄若虫在感病和健康植株嫩梢上的取食行为。【结果】柑橘木虱成虫与5龄若虫在感染黄龙病的酸橘上的取食行为有显著差异。5龄若虫比成虫更快地开始在韧皮部和木质部进行吸食,口针在韧皮部的总过程以及吸食时间显著长于成虫。此外,5龄若虫和成虫在EPG测定(同时饲菌)10 h后获菌率分别为37.5%和20.0%,若虫明显高于成虫。寄主植物感染黄龙病对5龄若虫的取食行为有一定的影响,表现在感病植株上的刺探次数、唾液分泌次数和韧皮部吸食次数都显著少于健康植株,而两者分泌唾液和韧皮部吸食时间没有显著差异。另外,在感病植株上首次韧皮部取食出现时间较在健康植株上要早。【结论】在同等时间下,柑橘木虱5龄若虫比成虫在感染黄龙病的酸橘上的取食能力更强、取食量更大、获菌率更高,原因可能是若虫需要更多的营养物质供其生长发育所致。寄主感染黄龙病对木虱5龄若虫的取食有利,使其更快地开始取食,而且更改取食位点次数变少,推测可能与黄龙病菌破坏了植物的防御有关。     

捕虱管蓟马的捕食、交配和产卵行为

观察了捕虱管蓟马的多种行为,认为该虫的日常行为为取食、行走、搜索、休息、交配和产卵;对所试验的5种害虫的喜好程度依次为椭圆蚧卵,柑桔木虱卵、褐圆蚧卵、柑桔粉虱卵、桔全爪螨若虫,褐圆蚧若虫、桔全爪螨卵、椭圆蚧若虫、柑桔木虱一龄 若虫,除柑桔木虱一龄若虫外,取食差异不显;捕虱管蓟马取食卵的量比若虫多,经T－检验分析,两无明显差异;室内饲养蓟马和田间采获蓟马的行为,及各行行为间差异,通过二因素方差分析显示不显;不同虫态蓟马取食时间长短依次为雌成虫、雄成虫、若虫、在食物充足的情况下,不同虫态之间几乎没有竞争,偶有成虫捕食幼虫现象发生。对该虫的交配行为及产卵行为作了详细的观察,发现雌蓟马成虫和雄蓟马成虫都多次交配;雄虫之间的性竞争十分激烈,而雌虫之间几乎没有竞争。     

氮肥促进Bt水稻和非Bt水稻上溴氰菊酯诱导的褐飞虱再猖獗能力

【目的】褐飞虱Nilaparvata lugnes是Bt水稻上重要的非靶标害虫之一,多种药剂会引起褐飞虱的再猖獗。本研究旨在探究氮肥使用下Bt水稻上褐飞虱对农药的生态适应性和再猖獗能力。【方法】取Bt水稻T1C-19(含cry1C*基因)和T2A-1(含cry2A*基因)稻苗分别施以0,100和250kg N/hm~2的氮肥,用不同浓度溴氰菊酯(0,1,3和6 mg/L)喷雾处理其上饲养的褐飞虱,分析氮肥处理的Bt水稻上褐飞虱对农药的生态适应性指标(若虫发育历期、若虫存活率、雌成虫体重、单雌产卵量和卵孵化率)。【结果】高浓度溴氰菊酯(6 mg/L)处理下褐飞虱的若虫存活率显著低于未处理组,而单雌产卵量则高于未处理组。方差分析表明,氮肥与溴氰菊酯相互作用可以显著影响褐飞虱的若虫存活率、雌成虫体重、单雌产卵量和卵孵化率。在0 kg N/hm~2处理下,溴氰菊酯处理对褐飞虱的产卵量无显著影响。在100和250 kg N/hm~2处理稻株上褐飞虱产卵量随着溴氰菊酯浓度的升高而增加。随着氮肥施用量的增加,褐飞虱若虫历期缩短,雌成虫体重增加,产卵量增加,褐飞虱若虫孵化率和存活率增高。相同氮肥施用量、溴氰菊酯同一浓度处理条件下,Bt水稻和常规水稻相比对褐飞虱的若虫发育历期、产卵量、卵孵化率和存活率均无显著影响。【结论】本研究结果表明,氮肥可以促进Bt水稻和非Bt水稻上溴氰菊酯诱导的褐飞虱再猖獗。     

不同寄主对梨小食心虫产卵选择的影响

【目的】为了明确不同世代的梨小食心虫Grapholita molesta(Busck)如何应对不同寄主进行产卵地点的选择。【方法】本文以受孕雌虫为研究对象,在室内进行受孕雌虫产卵对不同种类(桃、梨和苹果)的寄主嫩捎和果实的选择性试验。【结果】结果表明:(1)不同世代的受孕雌虫的产卵地点受到不同寄主种类的显著影响。越冬代、第2代和第3代受孕雌虫偏爱在梨果、桃梢上产卵,而第1代受孕雌虫偏爱在桃果和梨果上产卵。苹果梢和果实的引诱率最低。(2)卵的孵化率的变化趋势与受孕雌虫的落卵率一致。除了不同世代受孕雌虫在梨果上产的卵的孵化率存在差异以外,卵孵化率在同一世代的不同寄主果实、不同寄主嫩梢以及同一寄主的不同世代间差异不显著。【结论】因此,桃梢稳定吸引梨小食心虫产更多的可育卵,而桃果仅吸引第1代成虫产较多的可育卵,梨果吸引其余3代成虫产较多的可育卵。可见,梨小食心虫的产卵选择行为具有试探性,为后代占据优势生态位提供保障。     

稻株含氮量和密度对褐飞虱存活、发育和生殖特性的影响

对褐飞虱种群在不同含氮量稻株和若虫密度条件下的反应进行了研究。结果表明,若虫密度对褐飞虱存活的抑制作用随若虫密度提高而增强,但随寄主含氮量的增加而显著下降,表现为低含量的寄主植物可以增强对种群调节的负反馈作用。在低氮稻株上的饲养代数也明显影响若虫存活率,而在高氮稻株上饲养的不同代别褐飞虱之间则无显著差异。若虫率与稻株含氮量呈极显著的负相关,即在高若虫密度下寄主含氮量的增加可显著缩短褐飞虱若虫的发育历期。与高含氮量稻株上的褐飞虱种群相比,饲养在低含氮量稻株上的褐飞虱种群的若虫发育时间在高若虫密度下显著延长。在每盆40头褐飞虱若虫的密度下,成虫性比与稻株含氮量呈极显著的正相关,而在不同若虫密度下,随着若虫密度的增加雌性成虫比例显著下降。在每盆160头的若虫密度时低氮稻株上褐飞虱种群的性比低于0.3,显著低于在高氮稻株上的褐飞虱种群的性比0.85。在含氮量低的稻株上的雌成虫体重随若虫密度的增加极显著减少,连续取食第2代的雌成虫又比取食第1代时的轻。在所研究的所有若虫密度下,取食高含氮量稻株的褐飞虱种群的雌成虫寿命均为取食低含氮量稻株褐飞虱种群雌成虫寿命的3倍左右,差异极为显著。稻株含氮量和若虫密度对褐飞虱生殖力的作用最大,特别是在低氮稻株上若虫密度对褐飞虱生殖力的作用更为突出。在高含氮量稻株上的卵孵化率均随若虫密度的增加而有所下降,但在相同含氮量稻株上卵孵化率的差异均不显著。结果推测由于施用氮肥较多的水稻可以承受高密度的褐飞虱,提高了它们的迁出临界密度,减少了褐飞虱在克服逆境过程中的种群损失,从而造成更高的密度和更重的田间危害程度。     

黄龙病病菌在柑橘木虱体内的分布及感染动态

【目的】柑橘木虱Diaphorina citri Kuwayama是传播黄龙病病菌唯一的自然媒介昆虫,本文研究了黄龙病病菌在柑橘木虱各个发育阶段体内的分布以及感染动态,为有效防控柑橘木虱提供科学数据。【方法】利用常规PCR检测柑橘木虱若虫体内的黄龙病病菌,利用q RT-PCR和荧光原位杂交技术分别检测黄龙病病菌在柑橘木虱不同发育虫态体内的含量与分布形式。【结果】常规PCR可以在3-5龄若虫以及成虫体内检测到黄龙病病菌,而q RT-PCR除了3-5龄若虫外,还可以在2龄若虫体内检测到黄龙病病菌。卵和各龄期若虫中黄龙病病菌的含量是随着龄期的变大而不断增多。产卵盛期的成虫木虱体内黄龙病病菌的含量最高,显著高于产卵前期以及产卵后期。荧光原位杂交技术可以检测到4龄、5龄若虫及成虫体内的黄龙病病菌分布形态,病菌在若虫主要分布在U型含菌体内,而在雌雄成虫体内均是散布型分布。【结论】柑橘黄龙病在柑橘木虱的2-5龄若虫及成虫中都有感染,但其含量与分布形式因发育阶段不同而有显著差异。     

亚洲柑橘木虱和柚喀木虱过冷却点和体液结冰点测定

亚洲柑橘木虱Diaphorina citri Kuwayama和柚喀木虱Cacopsylla citrisuga YangLi均为柑桔上的重要害虫,前者为黄龙病的主要媒介昆虫,后者也已证实为黄龙病菌的携带者。本文对这两种木虱各龄若虫和成虫的过冷却点和体液结冰点进行了测定,结果表明,柑橘木虱过冷却点和冰点均以1龄若虫最低,平均值分别为-26.32℃和-26.22℃;成虫的过冷却点和冰点最高,分别为-19.60℃和-18.71℃;其它虫态过冷却点和冰点由低到高依次为2龄若虫、4龄若虫、5龄若虫、3龄若虫。柚喀木虱过冷却点和冰点也均以1龄若虫最低,平均值分别为-25.30℃和-25.08℃;5龄若虫的过冷却点和冰点最高,平均分别为-19.50℃和-17.69℃;其它虫态过冷却点和冰点由低到高依次为2龄若虫、3龄若虫、4龄若虫、成虫。两种木虱的比较结果表明,各发育阶段的表现不一致,柚喀木虱的3龄若虫和成虫过冷却点显著低于柑桔木虱,而4龄、5龄若虫则显著高于柑桔木虱;3龄若虫体液结冰点也显著低于柑桔木虱,但1龄、4龄却显著高于柑桔木虱。柑桔木虱雌雄成虫的过冷却点和体液结冰点差异不显著。研究结果表明两种木虱的过冷却点、体液结冰点都较低,因而可能具有较强的耐寒能力。     

Attraction of the cabbage looper to host plants and host plant odor in the laboratory

In a laboratory flight tunnel, mated female, unmated female, and male adult cabbage loopers, Trichoplusia ni (Hübner), exhibited chemically mediated anemotaxis (attraction) in response to intact potted cabbage plants (Brassica oleracea L.), leading to contact with the plant. Similar attraction responses were also observed by mated females to potted soybean (Glycine max (L.)), tomato (Lycopersicon esculentum Miller), and celery (Apium graveolens L.) plants in noncompetitive comparisons. Mated females, unmated females, and males flew to cabbage plants throughout the scotophase. Response rates for mated females were higher than for unmated females and males. Mated female cabbage loopers were attracted by odors of cabbage, soybean, tomato, or celery piped into a flight tunnel from single plants held in glass jars and not to odors of the non-host plant Setcreasea purpurea, or to humidified air. They were also attracted to water washings of cabbage at dosages of 0.4 to 2.0 gram equivalents, when presented on cotton dental wicks in the flight tunnel.     

Herbivore host plant selection: whitefly learns to avoid host plants that harbour predators of her offspring

Evidence is accumulating that herbivorous arthropods do not simply select host plants based on their quality, but also on the predation risk associated with different host plants. It has been suggested that herbivores exclude plant species with high predation risk from their host range. This assumes a constant, predictable predation risk as well as a rather static behaviour on the part of the herbivore; plants are ignored irrespective of the actual predation risk. We show that adult females of a small herbivore, the whitefly Bemisia tabaci, can learn to avoid plants with predatory mites that attack only juvenile whiteflies, while they accept host plants of the same species without predators. Predatory mites disperse more slowly than whiteflies; they cannot fly and walk from plant to plant. Hence, by avoiding plants with predators, the whiteflies create a temporary refuge for their offspring. We suggest that the experience of arthropod herbivores with risks associated with host plants plays an important role in their host plant selection.     

Increased plant growth and copper uptake of host and non-host plants by metal-resistant and plant growth-promoting endophytic bacteria

The effects of inoculation with two metal-resistant and plant growth-promoting endophytic bacteria (Burkholderia sp. GL12 and Bacillus megaterium JL35) were evaluated on the plant growth and Cu uptake in their host Elsholtzia splendens and non-host Brassica napus plants grown in natural Cu-contaminated soil. The two strains showed a high level of ACC deaminase activities. In pot experiments, inoculation with strain GL12 significantly increased root and above-ground tissue dry weights of both plants, consequently increasing the total Cu uptake of E. splendens and Brassica napus by 132% and 48.2% respectively. Inoculation with strain JL35 was found to significantly increase not only the biomass of B. napus, consequently increasing the total Cu uptake of B. napus by 31.3%, but Cu concentration of E. splendens for above-ground tissues by 318% and roots by 69.7%, consequently increasing the total Cu uptake of E. splendens by 223%. The two strains could colonize the rhizosphere soils and root interiors of both plants. Notably, strain JL35 could colonize the shoot tissues and significantly increase the translocation factors and bioaccumulation factors of E. splendens. These results suggested that Burkholderia sp. GL12 and B. megaterium JL35 were valuable bacterial resource which had the potential in improving the efficiency of Cu phytoextraction by E. splendens and B. napus in a natural Cu-contaminated soil.     

自然植物种群中病原菌与寄主植物相互作用的遗传学

在农业种群中,作物和菌病相互作用的遗传学已为人们所广泛研究,但对自然植物种群中病原菌与其寄主相互作用体系的某些重要现象却缺乏足够的重视。本文主要论述寄主与病原菌相互作用的遗传学本质;寄主抗性基因和病原菌毒性基因的获得代价及对各自适应力的影响;简单介绍了寄主-病原菌作用体系在种群水平上的遗传学内容及共进化的意义。     

Olfactory responses of Aphidius gifuensis to odors of host plants and aphid‐plant complexes

Abstract The olfactory responses of Aphidius gifuensis to odors from two host plants (Nicotiana tabacum and Brassica napus ssp.) and their complexes with different infestation levels of two host aphids (Myzus persicae and Lipaphis erysimi) were respectively examined in an olfactometer. The results showed that female A. gifuensis did not respond to odors of undamaged or mechanically damaged host plants, but significantly responded to odors of aphid/plant complexes. Moreover, A. gifuensis responded significantly to odors of both M. persicae and L. erysimi/plant complexes when host plants were infested by high levels of aphids, suggesting that quantity of aphid‐induced volatiles could be important for attracting A. gifuensis. When tested between aphid/plant complexes, A. gifuensis did not show its preference for either complex. The efficiency of A. gifuensis against aphids in open fields potentially could be improved by using its olfactory response to aphid/plant complexes.     

Effect of crop rotations involving host and non-host plants on vesicular-arbuscular mycorrhizal infection of host plants

Summary The effects of crop rotations involving two host (lettuce and lavender) and two non-host (cabbage and radish) plants on the development of mycorrhizal infection in host plants were studied in unsterile soil and in sterilized soil with or without rock phosphate and inoculated withGlomus mosseae. As in previous experiments, pre-cropping with non-host plants did not decrease VA infection in the host plants. On the other hand, pre-cropping with a host plant increased VA infection in the same or another host plant grown afterwards. These effects were noted irrespectively of rock phosphate additions and of soil sterilization.     

寄生植物对寄主植物的化学识别

植物间寄生关系的研究近年来受到了广泛的重视。大量的研究表明,寄主释放的次生物质对植物间寄生关系的建立和维持起了重要的调节作用。寄主植物的次生物质对寄生植物的化学防御和昆虫授粉等生态功能起重要的作用,寄主植物次生物质对寄生植物生理与生态的调节作用是受寄生植物基因调节的。更为重要的是寄主植物释放的次生物质成为寄生植物的种子萌发和吸器发生的异源识别物质。能够刺激寄生植物种子萌发的次生物质主要是倍半萜和氢醌类物质,而诱导吸器发生的物质则是酚酸、醌和黄酮类化合物,诱导吸器发生的核心结构是对苯醌。这些异源识别物质大多是寄主植物释放的化感抑制物质,显示寄生植物在化学防御方面要比寄主植物高级。异源识别化合物的活性与其氧化潜力显著相关。由于寄生植物中存在一抑制异源识别物质诱导吸器发生的调节过程,因此吸器的产生与寄生植物根部接触异源识别物质的浓度与时间呈正相关关系,这一调节过程对寄生植物准确识别寄主并寄生其上是十分重要的。对寄生植物和寄主植物间的化学识别关系的揭示有助于人们防治有害寄生植物和开发利用有价值的寄生植物资源。     

Myco-heterotrophy: when fungi host plants

Background

Myco-heterotrophic plants are partly or entirely non-photosynthetic plants that obtain energy and nutrients from fungi. These plants form a symbiosis with arbuscular mycorrhizal, ectomycorrhizal or saprotrophic fungi to meet their nutrient demands.

Scope

This Botanical Briefing summarizes current knowledge about myco-heterotrophy, discusses its controversial aspects and highlights future directions for research.

Conclusions

Considerable recent progress has been made in terms of understanding the evolutionary history, germination and nutrition of myco-heterotrophic plants. Myco-heterotrophic plants: (1) are diverse and often ancient lineages that have coevolved with fungi, (2) often demonstrate unusually high specificity towards fungi during germination and maturity, and (3) can either cheat common mycorrhizal networks supported by neighbouring photosynthetic plants to satisfy all or part of their energetic and nutritional needs, or recruit free-living saprotrophic fungi into novel mycorrhizal symbioses. However, several fundamental aspects of myco-heterotrophy remain controversial or unknown, such as symbiotic costs and physiology.Key words: Cheater, common mycorrhizal network, mutualism, myco-heterotrophy, non-photosynthetic, symbiosis