鸢尾属植物的组织培养与栽培研究进展

鸢尾属植物花色艳丽,花型多具特色,具有较高的观赏性,是园林绿化中常见的一类花卉,也是世界著名的宿根花卉之一。鸢尾属植物在盆栽观赏、切花生产、医药食品、园林绿化等领域均占有重要地位,可以产生良好的经济效益、环境效益、生态效益和社会效益。但鸢尾属植物繁殖方式主要为分株繁殖,增殖缓慢。为解决这类问题,并对鸢尾属资源开发与保护提供理论基础,本研究对近年来国内外鸢尾属植物的组织培养与栽培的进展与成果进行了综述。本综述对鸢尾属植物育种的研究方向进行了探讨与展望,旨在为鸢尾属植物的培育方法提供一定的科学依据。     

西藏鸢尾兰属(兰科)植物5个新记录种

通过对西藏兰科鸢尾兰属植物进行的系统调查、标本采集、查阅、整理和鉴定,发现了西藏鸢尾兰属植物5个新记录种,分别为:长苞鸢尾兰(Oberonia longibracteata Lindl.)、短耳鸢尾兰(O. falconeri Hook. f.)、裂唇鸢尾兰(O. pyrulifera Lindl.)、条裂鸢尾兰(O. jenkinsiana Griff. ex Lindl.)和长裂鸢尾兰(O. anthropophora Lindl.),并附有这些新记录种的特征照片。凭证标本保存于西藏高原生态研究所标本室(XZE)。目前西藏鸢尾兰属植物共有14种,编写出西藏鸢尾兰属植物的分种检索表,以期达到对该区鸢尾兰属植物资源鉴定识别和有效保护的目的。     

中国北方鸢尾属植物叶片解剖结构特征及分类学价值研究

以中国北方生长的鸢尾属9种植物为研究对象,利用光学显微镜对叶表皮细胞形状及大小、气孔大小、气孔分布及气孔密度、气孔指数等叶表皮构造特征进行观察,并探讨了叶表皮特征在鸢尾属内各个亚属、亚组间的分类学价值,结果表明：表皮细胞的形状和大小显示了同亚属或同亚组植物之间较为明显的亲缘关系,在区分鸢尾属下不同亚属或亚组植物上也有一定的分类学价值。气孔密度和气孔指数在鸢尾属内分类学价值不大,但却能很好地反映不同鸢尾属植物与生境之间的密切关系。并从表皮构造特征上证实了野鸢尾与射干有很强的亲缘关系,且近于鸢尾属内的其他植物的结论;此外,通过对鸢尾属植物叶横切解剖结构的观察：从维管束、横切面形状、表皮细胞与角质层、乳突、气孔、气室大小、叶肉细胞的分化这7个较为明显的特征上的相关性和差异性,探讨了由于生境的不同而产生的植物形态结构的差异。     

中国北方鸢尾属植物叶片解剖结构特征及分类学价值研究

以中国北方生长的鸢尾属9种植物为研究对象,利用光学显微镜对叶表皮细胞形状及大小、气孔大小、气孔分布及气孔密度、气孔指数等叶表皮构造特征进行观察,并探讨了叶表皮特征在鸢尾属内各个亚属、亚组间的分类学价值,结果表明：表皮细胞的形状和大小显示了同亚属或同亚组植物之间较为明显的亲缘关系,在区分鸢尾属下不同亚属或亚组植物上也有一定的分类学价值。气孔密度和气孔指数在鸢尾属内分类学价值不大,但却能很好地反映不同鸢尾属植物与生境之间的密切关系。并从表皮构造特征上证实了野鸢尾与射干有很强的亲缘关系,且近于鸢尾属内的其他植物的结论;此外,通过对鸢尾属植物叶横切解剖结构的观察：从维管束、横切面形状、表皮细胞与角质层、乳突、气孔、气室大小、叶肉细胞的分化这7个较为明显的特征上的相关性和差异性,探讨了由于生境的不同而产生的植物形态结构的差异。     

鸢尾属部分种种子微形态特征与系统演化关系

用HITACHI S-520型扫描电子显微镜对鸢尾属植物10个种及1变种、1外类群的种子微形态进行观察、比较分析,探讨了鸢尾属植物部分种种子微形态特征分类学意义及系统演化关系。结果表明：鸢尾属植物种子表面微形态特征具有种的稳定性,与分布区无关;同一种的种子凹、凸面微形态差异很大,同一类群比较时应选择相同部位观察。所研究的鸢尾种都为网状（网纹或负网纹）文饰,种间差异明显,微形态特征可用于鸢尾属间、属下系的等级划分,但不适于种下等级鉴别。研究给出了鸢尾属植物种子表面纹饰的系统进化关系,证明了种子表面微形态对鸢尾属植物分类及系统演化关系具有重要意义。     

云南野生鸢尾属植物种质资源及观赏应用

对云南野生鸢尾属植物的资源情况、分布、生态习性和生物学特性等进行了调查研究。结果表明云南有野生鸢尾属植物19种。大多数分布于西北部和中部。在较湿润的土壤上生长良好。花大色艳。观赏价值较高。据此提出了鸢尾的多种观赏应用形式。     

鸢尾属植物抗重金属Cd、Pb、Cu研究进展

鸢尾属植物为鸢尾科典型的经济植物,具有花色艳丽、适应能力强等优点,且在重金属污染修复方面作用显著。文章深入阐述重金属单一胁迫和复合胁迫对于鸢尾属植物的生长、光合作用、保护酶活性等方面的影响,梳理并分析了鸢尾属植物对重金属污染修复的现状以及研究进展,以期为准确把握该属植物的研究动态、开展进一步的深入研究和开发利用提供参考。     

长白山区鸢尾属植物资源及其开发利用

对长白山鸢尾属植物的种类、分布、储量、生境、鉴别及开发利用等方面做了评细地调查研究,为开发长白山区鸢尾属植物资源提供了科学依据。     

国产鸢尾属尼泊尔鸢尾亚属的研究

研究报道了国产鸢尾属尼泊尔鸢尾亚属植物,确认国产该亚属植物为三种一变种。     

甘肃省小陇山地区鸢尾属植物资源调查及2个新记录种

本文报道了甘肃小陇山地区鸢尾科（Iridaceae）鸢尾属（Iris L.）植物2个新分布记录种：长柄鸢尾（Iris henryi Baker）和薄叶鸢尾（Iris leptophylla Lingelsh.）。通过整理重新编制了小陇山地区鸢尾属植物的分种检索表。两种植物的发现进一步丰富了鸢尾属在全国的分布格局和本属在秦岭地区的种类,并为小陇山地区的物种多样性研究提供了新的分布信息。凭证标本存放于陇南师范高等专科学校植物标本室。     

COMPARATIVE REPRODUCTIVE BIOLOGY OF HERMAPHRODITIC AND MALE-STERILE IRIS DOUGLASIANA HERB. (IRIDACEAE)

A comparative study of the reproductive biology of male-sterile and hermaphroditic plants in a gynodioecious population of Iris douglasiana Herb. (Iridaceae) was conducted at the University of California's Marine Laboratory at Bodega Bay, California, between 1976–1979. Each year of the study, there were 11.1% male-sterile plants in the population, some of which began blooming at the same time as the earliest blooming hermaphrodites. Male-sterile flowers made up between 7–21% of the flowers produced during the male-sterile flowering period. Male-sterile flowers had smaller sepals and petals than hermaphrodites, there were fewer of them per square meter, and they had fewer pollinated stigmas than did hermaphroditic flowers. In a test to determine pollinator preference, intact hermaphroditic flowers tended to have more pollinated stigmas than did hermaphrodites with their stamens removed or those flowers with shortened sepals made to resemble the smaller male-sterile flowers. Floral phenology and nectar-flow patterns were similar in both types of flowers as were the kinds of amino acids and sugar rewards in the nectar. Male-sterile flowers, however, produced much less nectar per flower. There were no significant differences in the number of ovules per flower or the number of seeds produced per capsule between the two flower types, but the loss of seeds through larval predation was much greater in capsules from hermaphroditic flowers. Early flowering and setting of seed by plants with male-sterile flowers could give them a reproductive advantage over plants with hermaphroditic flowers which experience higher levels of larval predation later in the growing season.     

Nectar Production in Louisiana Iris Hybrids

Nectar is an important attractant for pollinators, and a plant's success in sexual reproduction can be influenced by the amount and concentration of nectar produced by its flowers. We studied nectar production over flower lifetime in Iris fulva, Iris brevicaulis, and four classes of hybrids-reciprocal F1's and backcrosses-between these species. Iris fulva produced less concentrated nectar than did I. brevicaulis, whereas I. brevicaulis flowers had a shorter life span. Hybrids were not intermediate, but they had the high nectar concentration of I. brevicaulis combined with the long life span of I. fulva flowers. Nectar production and concentration declined after the first day in all classes, but flowers continued to produce nectar until they were completely wilted. Backcrosses did not show a shift in mean or increased variation for the characters that distinguished the parental species; backcrosses toward I. fulva retained the high nectar concentration of I. brevicaulis, and backcrosses toward I. brevicaulis did not have a reduced flower life span. Overall, F1 hybrid flowers produced the highest amounts of nectar and nectar sugar over their life spans. These results, together with previously obtained data on pollinator choice in mixed arrays of the same flower classes, show that F1 hybrids between these species do not suffer from reduced attractiveness to pollinators. F1 individuals produced more nectar and nectar sugar than did their parents, and thus, they are possibly even more attractive to pollinators that forage for nectar.     

How floral displays affect geitonogamy in an upward foraging bumblebee‐pollinated protandrous plant

Reducing geitonogamy (pollen transfer among flowers within the same plant) has been suggested as a major selective force for plants with multiple flowers. The occurrence of geitonogamy is generally different among flowers within inflorescences; however, no researchers have examined whether plants enlarge their display size without increasing the possibility of geitonogamy by presenting more flowers at positions where they are less likely to be geitonogamously pollinated. We observed that bumblebee pollinators foraged upward within the tower‐shaped inflorescences of protandrous Megacodon stylophorus (C. B. Clarke) Harry Sm. Because M. stylophorus did not strictly bloom bottom‐up, there were substantial frequencies of geitonogamous pollination resulting from upward and horizontal pollen transfer. Although there was a strong correlation between total numbers of flowers plants produced and numbers of flowers presented on single days, proportions of flowers possibly geitonogamously pollinated were weakly correlated with total numbers of flowers. This might have been because plants with more resources enlarged their display size by producing more flowers on lower floors where flowers had a low probability of being geitonogamously pollinated. This study shows that the tower‐shaped inflorescences of M. stylophorus enlarge their size without more cost of geitonogamous mating, suggesting that geitonogamy acts as an important selective agent in the evolution of inflorescence architectures.     

喜盐鸢尾花色形成关键基因的克隆及表达分析

喜盐鸢尾(Iris halophila Pall.)及其变种蓝花喜盐鸢尾(I.halophila Pall.var.sogdiana(Bung)Grubov)因耐盐碱及其多种花色而具有盐碱地园艺开发价值。本文根据喜盐鸢尾内轮花被转录组测序结果,利用基因特异性引物从这2种植物中分别克隆了编码查尔酮合成酶(CHS)、查尔酮异构酶(CHI)、类黄酮-3',5'-羟基化酶类(F3'5'H-like)等基因的部分片段,并对它们在内轮花被中的表达水平进行实时定量PCR分析。序列分析结果确认在喜盐鸢尾中所克隆的CHS(311 bp)、CHI(457 bp)、F3'5'H-like(496 bp)3个基因(部分)未见文献报道与NCBI等数据库记录。其中F3'5'H-like基因与经典的属于细胞色素P450CYP75A亚家族的F3'5'H不同,而与万带兰的F3'5'H-like同属于CYP76AB亚家族,为一类新的蓝花相关基因。实时定量PCR表达分析结果表明,与黄花的喜盐鸢尾相比,蓝花喜盐鸢尾中CHS与F3'5'H-like显著上调表达,可能是其花色不同于喜盐鸢尾的主要原因。     

Cryptic dioecy and insect pollination in Rosa setigera Michx. (Rosaceae), a rare plant of Carolinian Canada

Rosa setigera is unique among known roses because it is truly dioecious, yet the plants and flowers are almost impossible to sex. Subtle differences in the inflorescences have been detected, for example, there are more flowers per inflorescence on male plants than on female plants and petal expansion from the day of opening to the next day is greater in females than in males; in addition, pollen from female plants appears somewhat collapsed and does not germinate. Pollinators ( Apis mellifera , other bees (Apidae), Eristalis tenax and other Syrphidae: Diptera) visit the blossoms mostly in the morning to collect pollen (there is no nectar) and in choice experiments do not discriminate between male flowers and female flowers on landing, but do spend significantly more time on the former. They do discriminate between freshly opened flowers and day-old flowers, and show marked preference for bouquets of five flowers vs . single flowers. The female plants, with smaller inflorescences and lesser interest to pollen foraging insects, seem to encourage them to forage at more flowers than do their male counterparts. This may be biologically significant for effective pollen flow in a dioecious pollenonly plant with pollenivorous pollinators.     

Pollinators shift to nectar robbers when florivory occurs,with effects on reproductive success in Iris bulleyana (Iridaceae)

• Studies have indicated that florivory and nectar robbing may reduce reproductive success of host plants. However, whether and how these effects might interact when plants are simultaneously attacked by both florivores and nectar robbers still needs further investigation.
• We used Iris bulleyana to detect the interactions among florivory, nectar robbing and pollination, and moreover, their effects on plant reproductive success. Field investigations and hand‐pollination treatments were conducted on two experimental plots from a natural population, in which Experimental plot was protected from florivores and Control plot was not manipulated.
• The flower calyx was bitten by sawflies to consume the nectary, and three bumblebee species were pollinators. In addition, the short‐tongued pollinator, Bombus friseanus, was the only robber when there was a hole made by a sawfly. The bumblebee had significantly shortened flower handling time when robbing, as compared to legitimate visits. Pollinator visitation and seed production decreased significantly in damaged flowers. However, seed production per flower after supplementary hand‐pollination did not differ significantly between damaged and undamaged flowers. Compared to the Experimental plot, bumblebees visited fewer flowers per plant in a foraging bout in the Control plot.
• The flowers damaged by florivory allowed B. friseanus to shift to a nectar robber. Florivory and nectar robbing collectively decreased plant reproductive success by consuming nectar resources, which may reduce attractiveness to pollinators of the damaged flowers. However, the changes in pollinator behaviour might be beneficial to the plant by reducing the risk of geitonogamous mating.

     

Pollination of Oncocyclus irises (Iris: Iridaceae) by night-sheltering male bees

Irises in the section Oncocyclus (Siems.) Baker ( IRIS: Iridaceae) grow throughout the Middle East and have large and dark-coloured flowers but no nectar reward available to flower visitors. Consequently, no reward-collecting pollinators have been observed visiting the flowers during daytime. The only visitors are solitary male bees ( Eucera spp.: Apidae) that enter the flowers at dusk and stay there overnight. Here we describe the mating system of Oncocyclus irises, and the role of night-sheltering male bees in their pollination system. Pollen viability in I. haynei on Mt. Gilboa was very high (>90%) throughout all floral life stages. Stigmas were receptive in buds and in open flowers, but not in older ones. Self-pollination yielded no fruits in three species, confirming complete self-incompatibility in Oncocyclus irises. On average, 1.9 flowers were visited by each male bee before it settled for the night in the last one. Moreover, Iris pollen was present on the dorsal side of 38.8% of males caught sheltering in flower models mounted near an I. atrofusca population, indicating that pollen is transferred between flowers by night-sheltering solitary male bees. We have surveyed 13 flowering populations of six Oncocyclus species for the presence of night-sheltering male bees as well as for fruit set. We found a positive correlation, indicating that sexual reproduction in Oncocyclus irises is dependent on night-sheltering solitary male bees. Based on their complete self-incompatibility, the absence of nectar-collecting visitors during the day, and the transfer of pollen grains by the night-sheltering solitary male bees, we conclude that fertilization of Oncocyclus irises is totally dependent on pollination by night-sheltering solitary male bees.     

Use of selected flowering plants in greenhouses to enhance aphidophagous hoverfly populations (Diptera: Syrphidae)

The addition of floral resources in a crop is the most commonly used conservation biological control strategy. The influence of additional floral resources on the abundance of aphidophagous syrphids has been studied in Mediterranean sweet-pepper greenhouses, in southeast Spain. Sweet alyssum and coriander were the plant species used as flowering plants, distributed in the greenhouse in several monospecific patches. In our first experiment the influence on syrphid pre-imaginal stages (larvae and pupae) was studied and adult stages were studied in a second experiment. A higher number of pre-imaginal syrphids was recorded in two replicated greenhouses where flowers were introduced, compared with two control greenhouses (without additional floral resources). To evaluate the effect on adults, 4 greenhouses were divided into 2 plots in each greenhouse and flowers were introduced in one plot per greenhouse. More hoverfly adults were observed in the plots where flowers had been introduced than in the control. The three most abundant syrphid species found were Eupeodes corollae, Episyrphus balteatus and Sphaerophoria rueppellii. Specimens from these species were dissected, and their pollen content was analysed to assess the food potential of the introduced flowers. The three syrphid species fed on pollen from both the flowering plants, as well as on sweet-pepper pollen. This conservation biological control strategy is an effective method to enhance native syrphid populations in Mediterranean sweet-pepper greenhouses.     

Review. The genic view of plant speciation: recent progress and emerging questions

The genic view of the process of speciation is based on the notion that species isolation may be achieved by a modest number of genes. Although great strides have been made to characterize 'speciation genes' in some groups of animals, little is known about the nature of genic barriers to gene flow in plants. We review recent progress in the characterization of genic species barriers in plants with a focus on five 'model' genera: Mimulus (monkey flowers); Iris (irises); Helianthus (sunflowers); Silene (campions); and Populus (poplars, aspens, cottonwoods). The study species in all five genera are diploid in terms of meiotic behaviour, and chromosomal rearrangements are assumed to play a minor role in species isolation, with the exception of Helianthus for which data on the relative roles of chromosomal and genic isolation factors are available. Our review identifies the following key topics as being of special interest for future research: the role of intraspecific variation in speciation; the detection of balancing versus directional selection in speciation genetic studies; the timing of fixation of alleles of major versus minor effects during plant speciation; the likelihood of adaptive trait introgression; and the identification and characterization of speciation genes and speciation gene networks.     

Influence of rol genes in floriculture

Traditionally, new traits have been introduced into ornamental plants through classical breeding. However, genetic engineering now enables specific alterations of single traits in already successful varieties. New or improved varieties of floricultural crops can be obtained by acting on floral traits, such as color, shape or fragrance, on vase life in cut-flower species, and on rooting potential or overall plant morphology. Overexpression of the rol genes of the Ri plasmid of Agrobacterium rhizogenes in plants alters several of the plant's developmental processes and affects their architecture. Both A. rhizogenes- and rol-transgenic plants display the "hairy-root phenotype", although specific differences are found between species and between transgenic lines. In general, these plants show a dwarfed phenotype, reduced apical dominance, smaller, wrinkled leaves, increased rooting, altered flowering and reduced fertility. Among the rol genes, termed rolA, B, C and D, rolC has been the most widely studied because its effects are the most advantageous in terms of improving ornamental and horticultural traits. In addition to the dwarfness and the increase in lateral shoots that lead to a bushy phenotype, rolC-plants display more, smaller flowers, and advanced flowering; surprisingly, these plants may have better rooting capacity and they show almost no undesirable traits. rolD, the least studied among the rol genes, offers promising applications due to its promotion of flowering. Although the biochemical functions of rol genes remain poorly understood, they are useful tools for improving ornamental flowers, as their expression in transgenic plants yields many beneficial traits.