Changes in Florets’Vertical Direction within Inflorescence Affects Pollinator Behavior,and Fitness in Trifolium repens

interactions,many flowers are known to display their attractive qualities,such as scent emission,flower rewards and floral vertical direction,in a rhythmic fashion.However,less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success.Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens.We observed the flowering dynamic characteristics(changes of vertical direction of florets,flowering number,pollen grain numbers,pollen viability and stigma receptivity over time after blossom)and the factors affecting the rate of flower bending in T.repens.Then we altered the vertical direction of florets in inflorescence of different types(upright and downward),and compared the pollinator behaviors and female reproductive success.Our results showed that florets opened sequentially in inflorescence,and then bend downwards slowly after flowering.The bending speed of florets was mainly influenced by pollination,and bending angle increased with the prolongation of flowering time,while the pollen germination rate,stigma receptivity and nectar secretion has a rhythm of“lowhigh-low”during the whole period with the time going.The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers,and they especially prefer to visit flowers with a bending angle of 30°–60°,when the flowers was exactly of the highest flower rewards(nectar secretion and number of pollen grains),stigma receptivity and pollen germination rate.The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers,but significantly lower than unmanipulated flowers.Our results indicated that the T.repens could increase female and male fitness by accurate pollination.The most suitable flower angle saves pollinators’visiting energy and enables them to obtain the highest nectar rewards.This coordination between plants and pollinators maximizes the interests of them,which is a crucial factor in initiating specialized plant-pollinator relationships.

配施有机肥对白三叶草生长及香蕉园土壤生态的改良作用

为探明香蕉园间作白三叶草(Trifolium repens L.)模式下配施纯羊粪和生物有机肥对白三叶草的生物量和营养元素含量及香蕉园土壤理化性质的影响,采用间作白三叶草+常规管理(CK)、间作白三叶草+施用纯羊粪、间作白三叶草+施用生物有机肥3个处理做对比分析。结果表明,间作条件下配施纯羊粪,白三叶草地上部和地下部的生物量分别显著增加17%和10%,地上部和地下部的N、P、K含量分别显著增加21%、33%、17%和13%、15%、53%,土壤有机质、pH、全氮和速效钾含量分别显著增加17%、3%、22%和3%;间作条件下配施生物有机肥,白三叶草地上部和地下部的生物量分别显著增加19%和25%,地上部和地下部的N、P、K含量分别显著增加26%、12%、5%和44%、50%、22%,土壤有机质、pH、全氮和速效钾含量分别显著增加42%、4%、33%和4%。由此可见,在香蕉园间作白三叶草模式下配施纯羊粪或生物有机肥均能显著提高白三叶草的生物量和N、P、K元素含量,同时还能改善香蕉园土壤生态,且配施生物有机肥优于配施纯羊粪。

白三叶水浸液对草坪草的化感作用

为探讨白三叶入侵禾本科草坪草原因,利用生物测定法研究不同浓度白三叶水浸液对多年生黑麦草、高羊茅、草地早熟禾三种禾本科草坪草种子萌发和幼苗生长的化感作用。结果表明,白三叶水浸液对多年生黑麦草、高羊茅和草地早熟禾三种草坪草种子发芽率、发芽势和幼苗苗高具有低浓度促进、高浓度抑制的双重效应,且抑制作用明显强于促进作用;对幼苗根长具有显著的抑制作用,且抑制作用随着白三叶水浸液浓度的增加而增强;对种子发芽指数、活力指数和幼苗鲜重的影响则因草坪草种类的不同而不同。结果表明,白三叶水浸液具有化感作用,影响三种草坪草的正常生长,是白三叶入侵禾本科草坪草的原因之一。

豫西地区白三叶草坪昆虫种类调查及群落分析

通过对河南省豫西地区主要城市白三叶Trifolium repens草坪昆虫群落的调查,经鉴定属12目36科75种,其中害虫种类为53种,天敌19种,其他昆虫2种。在害虫中,不同季节优势种不一样,春季的优势种是蚜虫,夏季的优势种是甜菜夜蛾Laphyma exigua和银纹夜蛾Argyrogramma agnata,秋季的优势种是三点盲蝽Adeiphocoris fasiaticollis和蛴螬。它们是综合治理的主要对象。

白车轴草中总黄酮提取工艺研究

基于超声波提取法探究提取白车轴草(Trifolium repens)中黄酮类物质的最佳工艺条件。以芦丁为空白对照,总黄酮得率为考察指标,通过亚硝酸钠-硝酸铝-氢氧化钠法,采用单因素试验及L9(33)正交试验设计,研究超声时间、乙醇浓度和液固比3种因素对白车轴草中黄酮类物质提取率的影响。结果表明,白车轴草总黄酮提取的最佳工艺条件为超声提取时间40 min、乙醇浓度50%、液固比60∶1(mL∶g)。在此条件下,白车轴草中总黄酮的提取率为2.853%。该试验设计方法高效、快速、经济,适用于白车轴草总黄酮提取工艺研究,并为白车轴草有效提取黄酮类物质提供试验依据。

白三叶坪用价值研究

通过白三叶Trifolium repens对花灌木、观赏草坪的侵入试验,用最直观的测试方法证明了开放性三叶草观赏草坪对园林景观的破坏性是非常巨大的,可在短期内使景观草坪失去观赏价值,并最终将其“吞噬”。但时至今日,三叶草对于草坪景观的危害性还只是停留在理论层面的讨论中,在造园实践中尚未引起足够的重视,许多园林种子公司仍将三叶草作为景观草种出售,不少城市园林造景中还在建植大片的开放性三叶草草坪。针对以上问题,提出了5条对策。

影响海法白三叶生长的营养元素及磷钾施用效果

取云南省广南畜牧场原生红砂壤土,在温室采用盆栽手段对指示植物海法白三叶进行矿物营养元素筛分和磷、钾施量试验。结果表明:影响海法白三叶在红砂壤上生长的主要矿物元素是磷、钾,其次为钼。施用磷肥效果明显,并且施磷量与白三叶地上部分生物量间呈极显著的直线正相关YP=0.851+9.93X(r=0.94)。初步推断以施24kg/hm2磷、26～52kg/hm2钾为白三叶当年定植的有效施用量。

Combining Ability in Mixtures of Prairie Grass and Clovers

Our objective was to evaluate the combining ability among cultivars of forage species, commonly sown in temperate regions of Argentina using a short rotation system. Three genetically diverse cultivars of prairie brome grass (Bromus catharticus, cv Copetona, cv ?andú and cv Tango), a white clover cultivar (Trifolium repens, cv Lucero) and a red clover cultivar (T. pratense, cv Tropero) were evaluated. A randomized complete block design experiment was established in 2005. The treatments included five monocultures and ten binary mixtures. The experiment was harvested 6 times over an 18-month period. Cumulative dry matter yield (kg?ha–1) was calculated as the sum of the six individual harvests. Diallel analysis provided estimates of the general combining ability (GCA) and specific combining ability (SCA). Red clover in monoculture and mixtures produced the highest yields, with significant positive GCA effects (P P P P < 0.01). Given the short-term nature of this study, we must limit our inference to short-term pastures (<2 years). Under these conditions, red clover had the best combination with prairie brome grass.

103份白三叶种质资源萌发期耐铜性评价

为评价103份白三叶种质资源萌发期的耐铜性,筛选出耐铜性白三叶种质资源,本研究对103份白三叶种质资源进行100 mg/L Cu^2+浓度胁迫和去离子水对照的萌发试验,对白三叶种质资源的发芽势、发芽率、发芽指数等萌发指标及总根长等根系生长指标进行统计学分析。结果表明:铜胁迫对白三叶萌发及根系生长均有抑制作用,不同白三叶种质资源各指标性状差异显著(p<0.05)。结合相关性分析和主成分分析,筛选出相对发芽指数、相对总根长、相对根系平均直径以及相对根系表面积等4项指标为白三叶耐铜性评价指标。通过加权隶属函数评价和聚类分析,筛选出CF022353等69份耐铜性白三叶种质资源,为白三叶耐铜性品种选育与推广提供了丰富的种质资源。

钙和钙离子通道阻断剂对丛枝菌根真菌吸收镉的影响

本试验以三叶草(Trifolium repense L.)为宿主植物,Glomusintra radices为供试菌种,通过分室系统将外生菌丝与植物根系分隔开,并对菌丝室加以不同含量水平的Ca2+、Cd2+和Ca2+通道阻断剂(Verapamil、LaCl3)进行处理,研究在菌丝吸收过程中Cd2+与Ca2+以及Ca2+通道之间的关系.试验结果表明,高Cd2+和LaCl3处理可促进菌丝发育;高Cd2+和Verapamil、LaCl3处理不同程度地降低了菌丝对Ca2+的吸收;高Ca2+和LaCl3处理则可提高菌丝对Cd2+的吸收.根据本试验结果可以认为,Cd2+在菌丝上的跨膜转运不是通过Ca2+通道完成,而且高Ca2+水平有利于Cd2+被菌丝吸收.

APPLICATION AND DEVELOPMENT OF ‘GREEN’ PREVENTIVE AND CONTROL TECHNOLOGIES IN GUIZHOU TEA PLANTATIONS

The application and development of ‘green’ preventive technologies in teaplantations is an important means of ensuring tea quality and ecologicalsafety. Ecological, agronomic and biological controls are the main preventivemeasures used in Guizhou Province. This paper summarizes the ‘green’preventive technologies being applied in Guizhou tea plantations, including theuse of plant defense inducers to regulate tea plant responses to pathogens,natural enemies to control pest species causing damage to shoots andTrifolium repens to control the main weed species. In addition, it summarizesthe integrated ‘green’ preventive technologies being used in Guizhou andprovides a foundation for the ecological maintenance of tea plantations.