早春播娘蒿对小麦的危害损失和经济阈值研究

本文从生态经济学角度,研究了鲁西平原麦区播娘蒿(Deseurainia sophia L.schur)与小麦的竞争关系,通过两年试验,得出了播娘蒿有关生物性状与小麦产量结构的相关关系;提出了播娘蒿密度与产量损失率的关系为幂函数曲线回归,即:y’=0.5226X~(0.6635)并求得当地生产水平下经济危害允许损失率(EIL)为2.56%,播娘蒿经济防除阈值(ET)模型:     

早春播娘蒿对小麦的危害损失和经济阈值研究

本文从生态经济学角度,研究了鲁西平原麦区播娘蒿(Deseurainia sophia L.schur)与小麦的竞争关系,通过两年试验,得出了播娘蒿有关生物性状与小麦产量结构的相关关系;提出了播娘蒿密度与产量损失率的关系为幂函数曲线回归,即:y’=0.5226X^0.6635)并求得当地生产水平下经济危害允许损失率(EIL)为2.56%,播娘蒿经济防除阈值(ET)模型:     

麦田杂草播娘蒿的初步研究

播娘蒿Descurainia sophia(L) Webb ex prantl,俗名婆婆蒿、黄花蒿、味味蒿。十字花科,播娘蒿属,是淮北地区麦田主要恶性杂草之一。从1982年秋播开始,我组承担了省农林厅植保处关于麦田杂草播娘蒿的研究课题,经过二年的调查研究,初步得出如下结果。一播娘蒿的生物学特性 1.形态特征;播娘蒿为种子繁殖的一年生草本植物,幼草叶柄及茎呈紫褐色,地下茎白色。第1、2张真叶对生,3叶后为互生,二回羽状复叶,全裂,裂片纤细,叶背面有绒毛,     

白梭梭开花及风媒传粉特点

对白梭梭的花期物候、开花式样、风媒传粉特点进行了观察,对柱头可授性、花粉一胚珠比(P／O)做了检测。白梭梭的花部特征有许多适应风媒传粉的特点：花小、无花冠、具光滑的花粉外壁、指状的柱头突起、较高的花粉一胚珠比。重力玻片法检测结果表明,白梭梭风媒传粉发生在晴朗、昼夜温差大、空气湿度高的4月中下旬;花期持续时间约14d,传粉盛期集中在前3d,花粉短距离传粉效率较低;对荒漠突发不良环境的适应,白梭梭具有爆发性的开花传粉机制。     

柑橘花器和种子中黄龙病菌的定量分布及应用

为准确、快速测定感病柑橘花器和种子中黄龙病菌（Candidatus Liberibacter asiaticus,Las）的含量,比较了SYBR Green Ⅰ实时荧光定量PCR（SGI-qPCR）和单管双引物对TaqMan探针qPCR（STDP-qPCR）的检测灵敏度,并用STDP-qPCR法定量检测了感病沙田柚花器和种子中的Las。结果显示,STDP-qPCR检测灵敏度为1×10⁰拷贝/μL,比SGI-qPCR高100倍;花器中的雄蕊、花瓣、雌蕊和花粉等组织,以及种子的种皮和胚乳组织中均可检测到Las,但含量差异较大,其中种皮组织中Las含量最高,达到109 842个细胞/μg DNA,花粉中的Las含量最低,为308个细胞/μg DNA,所有种壳中均未检测到Las;基于雄蕊组织的黄龙病分子诊断准确率达93.8%。表明Las在感病柑橘花器和种子中呈不均匀分布,基于雄蕊组织的黄龙病诊断方法可辅助用于该病害的高通量检测。     

化学药物GSC不同浓度对白菜型冬油菜主要性状的影响

以白菜型冬油菜品种鉴94为材料,研究化学药物GSC的不同浓度对白菜型冬油菜主要性状的影响。结果表明,GSC处理两次后,导致植株生长势变弱,而对结实力无显著影响;对油菜花冠和花瓣的生长有一定抑制作用,随着化学药物浓度的增加,花冠直径和花瓣面积呈减小趋势,雄蕊长度逐渐缩短,雌蕊无显著变化,T7浓度处理(第一次0.5 mg·L^-1和第二次0.6 mg·L^-1浓度处理)后,花丝萎缩,花药干瘪,出现大量不育花粉。GSC可以诱导白菜型油菜产生雄性不育,随着GSC浓度的增加,不育株数和失活花粉数也逐渐增加,在T7浓度,植株不育株率达86.49%,失活花粉率达89.30%;同时用此浓度处理后花粉囊发育不良,绒毡层细胞提前解体或随花粉粒退化一同消失,小孢子团紧贴内壁,数量变少。试验说明化学药物GSC对白菜型冬油菜具有一定的杀雄效果,同时杀雄效果与药物浓度有一定关系。     

豚草花器结构及排粉过程

豚草 Ambrosia artemisiifolia L.花序和花的结构已演化为适于风媒传粉:(1)花序和花很小;(2)雄头状花序排列成类似风媒植物的葇荑花序;(3)雄小花内有柱状结构协助排粉;(4)花粉粒有片状气室,增大浮力;(5)雌花柱头长并布满乳突状毛。雄花排粉有6个相互独立的过程:(1)雄花成熟;(2)花药伸出,迫使花冠裂片开放;(3)花粉囊开裂,尾状附属物伸直排粉;(4)花粉粒飘散;(5)柱状体伸长,“扫”出残留花粉;(6)花药、柱状体收缩,花冠裂片关闭如初。开花排粉要求高温低湿条件。高温促进花丝伸长花药伸出花冠,迫使开花,低湿促进花药干燥过程,有利于开裂排粉。     

山西省麦田杂草优势种群及其防除技术

调查表明,山西麦田杂草种类约75种,隶属于25科.以播娘蒿、荠菜、马齿苋、田旋花、藜和节节麦等为优势种群.出现频率最高的是播娘蒿,为61.2％,其次是荠菜,为52.6％.不同农田生态区域、同一区域春麦区与冬麦区、旱作地与水浇地麦田之间,杂草群落结构存在差异.部分麦田杂草呈现节节麦和雀麦等禾本科恶性杂草比重上升、传播蔓延加快的态势.采取以化学防除为主、农业措施为辅的综合防除技术,可有效控制麦田草害发生与危害.     

山东泰安地区麦田主要杂草田间分布型及应用研究

泰安位于鲁中南地区,麦田常见杂草主要有播娘蒿、荠菜、鹅不食,其中播娘蒿出现频率在90％以上,荠菜65%以上,鹅不食50％左右。这几种杂草均为一年生杂草,是我市麦田杂草防除的主要对象。为了给试验设计和调查取样提供理论依据,帮助分析杂草在农田发生发展动态,我们对这几种杂草分布型及应用进行了研究。一、材料与方法(一)分布型的调查和统计方法     

宁夏苹果花期霜冻敏感性指标研究

苹果花期霜冻指标是果园霜冻预报预警、防御的基础,本文运用人工模拟霜箱,以富士、嘎啦和乔纳金苹果为试验对象,设置过冷却模拟试验设5个温度梯度和4个持续时间共计20个试验处理,模拟研究了苹果花期霜冻敏感性指标。结果表明:苹果花苞期花瓣、盛花期花瓣和子房以及幼果期的幼果平均过冷却点在-3.51℃~-3.27℃,结冰点变化范围在-2.94℃~-2.65℃。苹果花期低温敏感范围在-2.5℃~-3.5℃之间,不同花器官、不同品种、不同低温持续时间和不同发育阶段之间有所差异,其中,在苹果花的花瓣、子房、雄蕊和雌蕊等不同花器官中,花瓣最不耐冻,子房和雌、雄蕊随温度降低变异较大;不同类型花耐受冻顺序为花苞半开花全开花;-2.5℃~-3.0℃温度处理下,致死率随持续时间增加明显,温度高于或低于这个范围,持续时间对致死率影响不大;3个苹果品种中,富士最不耐冻,其次是乔纳金和嘎啦。     

Infection of plum and nectarine flowers by Botrytis cinerea

The ability of Botrytis cinerea to infect plum and nectarine flowers was studied in moist chambers and in the orchard. Within 36 h of inoculation, the pathogen penetrated and colonized the stamens, styles and petals on shoots placed in moist chambers, causing blossom blight. Similar lesion development was observed following inoculation with dry and wet conidia, Hyphae were usually distorted in stylar tissue, but grew normally in petals and filaments. Growth of the fungus through filaments into the sepals or floral tubes, or through the transmitting tissue of the style into the ovary, was never observed. Symptoms of blossom blight were not observed on inoculated shoots in the orchard. The floral tube, bearing the sepals and stamens, dehisced within 14 days of fruit set and infected floral parts did not remain attached to young developing fruit. No relation was found between post-harvest decay and flower infection. Losses following post-harvest decay might have been caused by direct penetration of ripening fruit and not by flower infection. The importance of infected floral parts as a source of secondary inoculum on ripening fruit is discussed.     

Infection routes for Sclerotinia sclerotiorum in apetalous and fully petalled winter oilseed rape

Near‐isogenic lines (NILs) of apetalous (AP) and fully petalled (FP) winter oilseed rape were used to investigate infection by Sclerotinia sclerotiorum, which occurs mainly via infected petals adhering to leaves in FP oilseed rape. AP1 flowers had an average of 1·4 and 0·8 petals per flower in field and polytunnel experiments, respectively. In field experiments there were no significant differences between counts of FP1 petals, FP1 stamens and AP1 stamens adhered to leaves during flowering. At any one sample time, significantly more stamens tested positive for S. sclerotiorum on AP1 than FP1 NILs, e.g. in 2004, at early flowering 37·5% and 24·2% of stamens tested positive on AP1 and FP1 NILs, respectively. In polytunnel experiments, there were significantly more sclerotinia lesions per plant in the FP1 than in the AP1 NIL. The AP1 NIL did not avoid infection completely, probably because it produced some petals, and lesions were initiated from adhered stamens as well as petals. However, while 8·5% and 16·3% of petals initiated lesions in FP1 and AP1 NILs, respectively, only 2·5% and 1·0% of stamens initiated lesions in FP1 and AP1 NILs, which suggests stamens may be less infective than petals. In field experiments the AP1 NIL had significantly less incidence of sclerotinia stem rot than the FP1 NIL in 2004 (4·9% and 7·0%, respectively). However, there was no significant difference in stem rot incidence between AP and FP lines in 2005 (3·6% and 4·3%, respectively) or 2006 (5·5% and 3·9%, respectively).     

Insect pollinators of the invasive plant, Rosa multiflora (Rosaceae), in Iowa, USA

Invasive species often require mutualistic relationships to successfully invade new environments. Insect pollination is an example of a mutualism that is required for seed-set in the invasive species, Rosa multiflora Thunb. (Rosaceae), an obligate outcrosser. To determine the insect pollinators visiting R. multiflora flowers in Iowa, USA, we collected insects on yellow sticky traps placed on plants during the period of blooming and visually observed insects visiting the flowers. The common insect orders that were collected on the sticky traps included Coleoptera, Diptera, Hemiptera, Hymenoptera, Mecoptera, and Thysanoptera. Many of the insects found on the sticky cards were known to feed on pollen. However, we did not collect Apidae (bumble bees and honey bees) on the sticky cards. We observed Bombus spp. and Apis mellifera foraging on the flowers. Syrphid flies were the most commonly observed taxa visiting the flowers. Our results indicate that R. multiflora is utilizing common generalist insect pollinators in Iowa and that pollination is not a limiting factor for this invasive species.     

Infection of Cranberry Flowers by Monilinia oxycocci and Evaluation of Cultivars for Resistance to Cottonball

ABSTRACT Infection of cranberry flowers by conidia of Monilinia oxycocci, the cottonball pathogen, was investigated using a squash-mount histological method. Conidia germinated on anthers, nectaries, petals, and stigmata, but not styles. The stigma was the only flower part penetrated by the fungus, but no specialized infection structures were noted. Both fungal and pollen germ tubes grew through the stylar canal and made contact with ovules and nucellar tissue by 72 h after inoculation and pollination. Cottonball incidence was greatest when stigmata were inoculated; the low level of cottonball that resulted from inoculation of other flower parts and in noninoculated flowers was attributed to contamination of stigmata. In greenhouse tests, cottonball incidence was 25, 28, 31, and 38% for cvs. Searles, Pilgrim, Ben Lear, and Stevens, respectively, and was greater for M. oxycocci isolate 593 than isolate 591. We conclude that the stigma is the sole floral infection court for conidia of M. oxycocci and that the most popular cranberry cultivars in Wisconsin do not differ in inherent resistance to cottonball. The relevance of these findings to the long-term management of cottonball is discussed.     

Fruit set and the diurnal pollinators of the invasive Lantana camara and the endemic Lantana peduncularis in the Galapagos Islands

Fruit set is highly relevant to a plant's reproductive success. Fruit set can vary due to predation on flowers, pollinator services and/or resource availability. Reproductive success, measured as the fruit set of the invasive Lantana camara and the endemic Lantana peduncularis in the cool–dry season and the warm–wet season of the Galapagos Islands, was studied. Also, autonomous self‐pollination ability and seed viability were probed for both species. Furthermore, flower visitors and their activity were registered for both species during the warm–wet season. Lantana peduncularis produced fewer flowers per inflorescence, but had a higher fruit set in the cool–dry season, compared to the warm–wet season. In contrast, the fruit set in L. camara did not change seasonally. The fruit set in L. camara was higher than in L. peduncularis in the warm–wet season. Moreover, ～18% of the bagged flowers of the invasive Lantana produced fruits by autonomous self‐pollination, while for the endemic Lantana, the rate of autonomous self‐pollination was very low. More than 80% of the fruits for both species had at least one viable seed per fruit. The number of pollinators and their frequency, inflorescence‐ and flower‐visiting rates and the duration of the visit per flower were higher in the invasive Lantana than in the endemic one. The endemic Lepidoptera Urbanus galapagensis (the main pollinator of both Lantana species) and the introduced Hymenia perspectalis were observed pollinating both Lantana species. These results indicate that the alien L. camara is more attractive to pollinators and it has reproductive advantages regarding fruit set in comparison with L. peduncularis, factors that contribute to the colonization pattern of this invasive species.     

Limitations on the recruitment of the rare sand shrubby legume Eremosparton songoricum (Fabaceae) in Gurbantunggut Desert, China

Eremosparton songoricum,a rare and endemic sand dune plant,appears to be experiencing recruitment failure.The structure of five populations from the Gurbantunggut Desert,China,was investigated for recruitment patterns,and two of them were examined for flowering,pollination and seed germination limits on regeneration.The results showed that total 150 seedlings only occurred on line transects in riverside Dure population,but they all died half a month later;no seedlings occurred in other four hinterland desert populations indicating recruitment was a failure at all populations although flowers were plentiful.Reproductive success depends on pollinators.Nectar is 'reward' for pollinators,with 0.06 μL-0.12 μL and 0.15 μL-0.35 μL per flower in Dure and Kabu populations,respectively,in continuously two secreting days.Spontaneous self pollination is rare with nearly zero fruit production.Geitonogamous self pollination is predominant with 14.47% fruit set.Seed mass in the riverside Dure population was significantly greater than that in other hinterland desert populations.Consequently,the Dure population exhibited a significantly higher germination rate(about 90%) than those in other populations(about 30%).Results suggested that recruitment failure of E.songoricum is not due to flower shortage,pollination limitation,or poor seed germination but environmental pressure and/or human disturbance.     

Histology of waxflower (Chamelaucium spp.) flower infection by Botrytis cinerea

Botrytis cinerea infects waxflower (Chamelaucium spp.) flowers and can induce them to abscise from their petioles before disease becomes evident. Botrytis cinerea infection of flowers was studied on two waxflower cultivars by light and electron microscopy. Pot‐grown waxflower flowers were harvested, inoculated with aqueous suspensions of B. cinerea conidia, incubated at 20–22°C and >95% RH and examined within 96 h post‐inoculation (hpi). Conidial germination on petals started 4 hpi, penetration via germ tube tips was 6 hpi and protoappressoria were formed 8 hpi. Germination on petals approximately doubled every 4–6 h to 18 hpi. Conidial germination was ca. 50% at 22–24 hpi. Botrytis cinerea infected most waxflower flower organs, including petals, anthers and filaments, stigma and hypanthium, within 24 hpi. Hyaline and lobate appressoria were observed 36 hpi. Infection cushions on stamen bases were formed 36 hpi by saprophytic hyphae that originated from anthers. This infection process can give rise to tan‐coloured symptoms typical of botrytis disease that radiate from this part of the flower. Subcuticular hyphae were present at high density near stamen bases and evidently resulted from multiple penetrations from single infection cushions. The subcuticular hyphae grew within the hypanthium and towards the centre of the floral tube. When flower abscission occurred, floral tube tissues close to the abscission zone remained uninfected. This observation infers possible transmission of a signal (e.g. ethylene) upon B. cinerea infection. Thus, B. cinerea causes flower abscission apparently as a defence response.     

几种除草剂对冬麦田杂草的防除效果

通过田间药效试验,比较不同除草剂对当前南疆地区冬麦田播娘蒿、萹蓄、硬草等杂草的防除效果,为科学、安全、高效应用除草剂提供依据。结果表明,药后50 d,10％苯磺隆可湿性粉剂18．0 g a．i．／hm2＋5％唑啉草酯·炔草酯乳油37．5 g a．i．／hm2、75％苯磺隆水分散粒剂18．0 g a．i．／hm2＋10％乙羧氟草醚乳油12．0 g a．i．／hm2＋5％唑啉草酯·炔草酯乳油37．5 g a．i．／hm2、37％炔·苄·唑草酮可湿性粉剂166．5 g a．i．／hm2对播娘蒿的株防效、鲜质量防效均为100％,对萹蓄的鲜质量防效均在92％以上,对硬草的株防效、鲜质量防效均在88％以上,且对小麦生长安全。     

Breeding system and its consequence on fruit set of a rare sand dune shrub Eremosparton songoricum(Fabaceae:Papilionoideae):implications for conservation

The breeding system and its consequence on fruit set of Eremosparton songoricum(Litv.) Vass.,a rare shrubby legume occurring in moving or semi-fixed sand dunes of Central Asian deserts,were examined by manipulative experiments and observational studies in natural populations during the period of 2007-2009.The results showed that E.songoricum exhibits a mixed mating system.It is self-compatible,but depends strictly on pollinators to set fruits.Only two effective pollinators were detected and they triggered the specialized pollination mechanism(a 'brush type' and 'tripping mechanism').Geitonogamy becomes predominant in natural populations,because(74.5±1.3)% of visiting activity happened within or between inflorescences and(24.3±1.4)% occurred between ramets.As a result,inbreeding depression caused by geitonogamous selfing inevitably happened under natural conditions,showing 2.36 times less fruit set than was achieved by hand cross-pollination.The results explained the rarity of the species due to its breeding system,and will assist to develop suitable conservation strategies in severe desert environments.     

Floral traits and pollination system of Zygophyllum xanthoxylum in the managed and wild populations in an arid region of Northwest China

Zygophyllum xanthoxylum, which belongs to Sarcozygium of Zygophyllaceae, is one of the ecologically important species in Northwest China. In order to understand the pollination system of Z. xanthoxylum, we investigated the following characteristics of this species in the Urat Desert-grassland Research Station in western Inner Mongolia of China: flowering dynamics, pollen viability, pollen limitation, floral visitors and breeding system. The results showed that the flowering period and flowering peak were different between the wild and managed populations, being longer in the managed population. Z. xanthoxylum was pollen-limited, and pollen limitation was more intense in the wild population than in the managed population. Chalicodoma deserticola(Hymenoptera) was found to be the most frequent pollinator in the wild population, while Anthophora fulvitarsis(Hymenoptera) was the most frequent and effective visitor in the managed population. Out-crossing was dominant in the breeding system and self-pollination just played an assistant role to assure the reproduction of Z. xanthoxylum.