Floral Tissues Research Articles

Impact of managed stingless bee and western honey bee colonies on native pollinators and yield of watermelon: A comparative study

Watermelon (Citrullus lanatus) is an important crop cultivated in India and other warmer regions of the world. The crop is dependent on insect pollinators for its fruit set. However, information about pollination ecology in Indian states remains undetermined. We used a replicated field-scale experiment to identify the native pollinators and their foraging behaviour, including abundance, visitation rate, duration of visit, and pollination efficiency. We compared treatments with open-pollinated, hand-pollinated and the addition of two managed pollinator species to estimate the yield enhancement potential of managed stingless bees and western honey bees and their impact on native pollinator species. We found that ants, bees, butterflies, beetles, and wasps visited the flowers either for nectar, pollen, and/or floral tissue. Regarding the ‘pollinator importance’ value of the visitors, Halictus acrocephalus and Lasioglossum funebre were the most effective native pollinators. Despite their contribution, the plants showed a significant pollination deficit in the open-pollinated system which can be overcome by supplementary pollination services through the management of western honey bees (Apis mellifera) and/or stingless bees (Tetragonula iridipennis). However, the application of A. mellifera colonies greatly reduces the abundance, visitation rate and foraging time (amount of time spent per visit on a flower) of native pollinators. Hence, the utilization of managed stingless bee colonies for pollination services is more suitable and has a lesser impact on native pollinator species, which may lead to sustainable agricultural practices.

Fine mapping and candidate gene analysis of the orange petal colour gene Bnpc2 in spring rapeseed (Brassica napus)

AbstractPetal colour is considered as an important trait and major visual signal for insect‐pollinated plants and landscaping. In previous study, we isolated and identified two genes (BnPC1 and BnPC2) that control the orange petal colour (OPC) in rapeseed. To identify the molecular markers linked to the orange petal colour, we constructed a B. napus linkage map with four newly developed simple sequence repeat (SSR) markers and nine insertion–deletion (InDel) markers using BC5II, a near isogenic line population segregated at the BnPC2 locus. The BnPC2 gene was flanked by Indel‐3 and Indel‐20 and was found to represent a 27‐kb (3.721–3.748 Mb) region on A09 of B. napus. High‐pressure liquid chromatography analysis revealed that, compared to yellow petals, orange petals exhibit significantly increased zeaxanthin, β‐carotene and lutein contents and a relatively decreased violaxanthin content. Expression profiling confirmed that BnaA09.ZEP (zeaxanthin epoxidase) is an important candidate gene for BnPC2 and is predominantly expressed in floral tissues. Overall, our results provide a basis for understanding the molecular mechanisms underlying the orange petal colour trait in B. napus.

Gene expression underlying floral epidermal specialization in Aristolochia fimbriata (Aristolochiaceae).

The epidermis constitutes the outermost tissue of the plant body. Although it plays major structural, physiological and ecological roles in embryophytes, the molecular mechanisms controlling epidermal cell fate, differentiation and trichome development have been scarcely studied across angiosperms, and remain almost unexplored in floral organs. In this study, we assess the spatio-temporal expression patterns of GL2, GL3, TTG1, TRY, MYB5, MYB6, HDG2, MYB106-like, WIN1 and RAV1-like homologues in the magnoliid Aristolochia fimbriata (Aristolochiaceae) by using comparative RNA-sequencing and in situ hybridization assays. Genes involved in Aristolochia fimbriata trichome development vary depending on the organ where they are formed. Stem, leaf and pedicel trichomes recruit most of the transcription factors (TFs) described above. Conversely, floral trichomes only use a small subset of genes including AfimGL2, AfimRAV1-like, AfimWIN1, AfimMYB106-like and AfimHDG2. The remaining TFs, AfimTTG1, AfimGL3, AfimTRY, AfimMYB5 and AfimMYB6, are restricted to the abaxial (outer) and the adaxial (inner) pavement epidermal cells. We re-evaluate the core genetic network shaping trichome fate in flowers of an early-divergent angiosperm lineage and show a morphologically diverse output with a simpler genetic mechanism in place when compared to the models Arabidopsis thaliana and Cucumis sativus. In turn, our results strongly suggest that the canonical trichome gene expression appears to be more conserved in vegetative than in floral tissues across angiosperms.

Floral infrared emissivity estimates using simple tools

BackgroundFloral temperature has important consequences for plant biology, and accurate temperature measurements are therefore important to plant research. Thermography, also referred to as thermal imaging, is beginning to be used more frequently to measure and visualize floral temperature. Accurate thermographic measurements require information about the object’s emissivity (its capacity to emit thermal radiation with temperature), to obtain accurate temperature readings. However, there are currently no published estimates of floral emissivity available. This is most likely to be due to flowers being unsuitable for the most common protocols for emissivity estimation. Instead, researchers have used emissivity estimates collected on vegetative plant tissue when conducting floral thermography, assuming these tissues to have the same emissivity. As floral tissue differs from vegetative tissue, it is unclear how appropriate and accurate these vegetative tissue emissivity estimates are when they are applied to floral tissue.ResultsWe collect floral emissivity estimates using two protocols, using a thermocouple and a water bath, providing a guide for making estimates of floral emissivity that can be carried out without needing specialist equipment (apart from the thermal camera). Both protocols involve measuring the thermal infrared radiation from flowers of a known temperature, providing the required information for emissivity estimation. Floral temperature is known within these protocols using either a thermocouple, or by heating the flowers within a water bath. Emissivity estimates indicate floral emissivity is high, near 1, at least across petals. While the two protocols generally indicated the same trends, the water bath protocol gave more realistic and less variable estimates. While some variation with flower species and location on the flower is observed in emissivity estimates, these are generally small or can be explained as resulting from artefacts of these protocols, relating to thermocouple or water surface contact quality.ConclusionsFloral emissivity appears to be high, and seems quite consistent across most flowers and between species, at least across petals. A value near 1, for example 0.98, is recommended for accurate thermographic measurements of floral temperature. This suggests that the similarly high values based on vegetation emissivity estimates used by previous researchers were appropriate.

Florivory by the occupants of phytotelmata in flower parts can decrease host plant fecundity.

Some types of plant accumulate liquid in their inflorescences creating phytotelmata. These environments protect the flowers against florivory, although they may be colonized by aquatic or semi-aquatic florivorous insect larvae, whose effects on the fitness of the plants remain unclear. We tested the hypothesis of floral antagonism by the occupants of phytotelmata, which predicts that florivory by the occupants of the phytotelmata represents a cost to the female fitness of the plant, reducing its fecundity. We manipulated experimentally the infestation by 3 florivores larvae species occupants of phytotelmata in inflorescences of Heliconia spathocircinata (Heliconiaceae) to test for negative direct trophic effects on the fecundity of the flowering and fruiting bracts. We found that the foraging of the hoverfly (Syrphidae) and moth (Lepidoptera) larvae in the inflorescences contributed to a decline in the fecundity of the plant. While the lepidopteran impacted fecundity when foraging in both flowering and fruiting bracts, the syrphid only affected the fruiting bracts, which indicates that the nectar and floral tissue are the principal resource exploited by the hoverfly. By contrast, soldier fly (Stratiomyidae) had a neutral effect on fecundity, while foraging in flowering or fruiting bracts. These findings corroborate our hypothesis, that herbivory by the larval occupants represents cost to the host plant having phytotelmata. The negative influence of this foraging on plant fecundity will nevertheless depend on the consequences of the exploitation of resources, which vary considerably in ephemeral habitats such as the phytotalmanta of flower parts.

Nectar robbing and plant reproduction: an interplay of positive and negative effects

Nectar robbers are animals that extract nectar through holes made in floral tissues. This behaviour has a wide spectrum of consequences for the plant that range from negative, to neutral, to positive according to life history traits of the interacting organisms and the ecological mechanisms involved. Lonicera etrusca has long tubular flowers producing large quantities of nectar and undergoing high levels of nectar robbing. Despite this, robbing seems to have neutral effects on the reproduction of the species. The aim of this work is to understand why this pollinator‐dependent plant is not affected by an interaction that is commonly detrimental for plants. To achieve this goal we try to answer two questions: 1) do nectar robbers deposit suitable pollen for plant reproduction after a visit? And, 2) is the visitation rate of legitimate visitors affected by nectar robbing? We experimentally studied the details of the reproductive compatibility system of the plant and compared pollen tube growth after single visits of the main nectar robbers. We made observations on plants of three populations to study the effect of robbers on the visitation rates of legitimate foragers. The results revealed that nectar robbers effectively perform cross‐pollination. Visitation rates of legitimate visitors are reduced by nectar robbing. The net neutral effect observed for L. etrusca is the result of two processes: on one side the direct positive effect of nectar robbers acting as pollinators, and on the other, a negative indirect effect caused by the decrease in visitation rates of legitimate visitors. Since the number of ovules in this species is low, both legitimate visitors and robbers contribute to an efficient cross‐pollination. This example illustrates how neutral effects for the plant can arise as the final result of a complex interaction between plants, legitimate visitors and robbers.

Quantitative analysis of auxin metabolites in lychee flowers.

To investigate the modulation of endogenous indole-3-acetic acid (IAA) level by biosynthesis and inactivation during floral development, IAA and its metabolites were analyzed by LC-ESI/MS/MS in Lychee (Litchi chinensis Sonn.) flowers. In the bloomed flowers, the level of free IAA was higher in males than in females. In contrast, the total sum level of IAA metabolites was higher in females than in males, suggesting a higher biosynthetic activity of IAA in the females before the bloom. A detailed time-course analysis from the bud stage to the developing flower stage showed higher levels of IAA in females than males. The major metabolites were oxidized IAA in both sexes. The results suggest that IAA is involved in the maturation of female floral tissues in lychee, and oxidative metabolism plays an essential role in controlling the free IAA levels therein.

In Silico Identification of the Complex Interplay between Regulatory SNPs, Transcription Factors, and Their Related Genes in Brassica napus L. Using Multi-Omics Data.

Regulatory SNPs (rSNPs) are a special class of SNPs which have a high potential to affect the phenotype due to their impact on DNA-binding of transcription factors (TFs). Thus, the knowledge about such rSNPs and TFs could provide essential information regarding different genetic programs, such as tissue development or environmental stress responses. In this study, we use a multi-omics approach by combining genomics, transcriptomics, and proteomics data of two different Brassica napus L. cultivars, namely Zhongshuang11 (ZS11) and Zhongyou821 (ZY821), with high and low oil content, respectively, to monitor the regulatory interplay between rSNPs, TFs and their corresponding genes in the tissues flower, leaf, stem, and root. By predicting the effect of rSNPs on TF-binding and by measuring their association with the cultivars, we identified a total of 41,117 rSNPs, of which 1141 are significantly associated with oil content. We revealed several enriched members of the TF families DOF, MYB, NAC, or TCP, which are important for directing transcriptional programs regulating differential expression of genes within the tissues. In this work, we provide the first genome-wide collection of rSNPs for B. napus and their impact on the regulation of gene expression in vegetative and floral tissues, which will be highly valuable for future studies on rSNPs and gene regulation.

Efficient mini-prep RNA extraction from Dendrobium floral tissues rich in polysaccharides for validation of reference genes during flower development

Efficient mini-prep RNA extraction from Dendrobium floral tissues rich in polysaccharides for validation of reference genes during flower development

Breeding System and Pollination of Thermopsis divaricarpa (Fabaceae: Papilionoideae) in the Southern Rocky Mountains

Thermopsis divaricarpa (Fabaceae) is a common wildflower in the montane zone of the Colorado Rocky Mountains, but its reproductive ecology is still largely unknown. Montane meadows are recognized for their relatively high species richness and important ecosystem services. Thus, knowledge of the reproductive ecology of T. divaricarpa is useful when assessing community-level responses to climate change in the montane zone of the Rockies. We investigated the phenology, breeding system, and pollination of this species in the southern Rocky Mountains of Colorado. Our results suggest that T. divaricarpa flowers from early June to mid-July, exhibits a facultative xenogamous breeding system, and may be pollinated by bumble bees. Pollen grains of T. divaricarpa are singular, ellipsoidal, and tricolpate. Beetles consume floral tissue, but their role as pollinators is questionable.

Regulatory mechanisms underlying florigenesis in Vanilla planifolia Andrews: A study of MADS-box gene family

ABSTRACT Orchid flowers have unique floral organisation which make them indispensable to the floral industry. The MADS-box gene family encodes for transcription factors that are involved mainly in floral organisation. This study was conducted on Vanilla planifolia, which is an important orchid that is commercially exploited by the food industry for a highly valued flavour, vanillin. V. planifolia transcriptome was analysed and 33 MADS-box transcripts that encode putative MADS-box proteins, were identified. Phylogenetic analysis of the VpMADS proteins with other closely related plant species showed clear clustering into type I and type II. Protein characterisation, duplication events, and their evolutionary analysis were performed. The spatio-temporal expression profile for VpMADS genes at different plant developmental stages showed high expression of these genes in specific floral tissues. Secondary and tertiary structural analyses was also done for 13 MADS-box proteins representing each sub-class and their 3D structures were deduced. This study provides a basic understanding of the functioning of MADS-box gene family in V. planifolia and paves the path for functional characterisation of selected VpMADS genes in planta and in a heterologous system for managing the commercially important traits in this orchid.

SVP-like gene PavSVP potentially suppressing flowering with PavSEP, PavAP1, and PavJONITLESS in sweet cherries (Prunus avium L.)

The MADS-box transcription factor SHORT VEGETATIVE PHASE (SVP) gene have important functions in flowering and dormancy regulation. However, the molecular mechanism of PavSVP regulating flowering and dormancy in sweet cherry remains unknown. We identified a MADS-box gene SVP-like named PavSVP from sweet cherry, which was closely to PmSVP and PpSVP from Prunus mume and Prunus persica by using phylogenetic tree analysis, suggesting a conserved function with these evolutionarily closer SVP homologs. Subcellular localization analysis indicated that, PavSVP was localized in the nucleus and cytomembrane. PavSVP expression in sweet cherries were observed in vegetative and floral tissues, but much higher level in flower buds. The seasonal expression level of PavSVP was higher during the stage of summer growth in flower buds, and declined gradually toward dormancy and flower initiation. Ectopic expression of PavSVP induced a delayed flowering and the occurrence of abnormal flowers, including curly sepals and plicated siliques in Arabidopsis. Furthermore, protein interaction analysis showed that PavSVP interacted with PavSEP, PavAP1 and PavJONITLESS. Unlike PavSVP, over-expression of PavSEP in Arabidopsis caused early flowering phenotype. In addition, the expression of PavSEP in flower buds was low in summer. These results will help reveal the molecular mechanisms of PavSVP in maintaining the suppression phase of flowering in sweet cherry during summer and winter.

Thermogenesis in four species of Schismatoglottis Calyptrata Clade (Schismatoglottideae: Araceae)

Spadix temperature was measured in Schismatoglottis ahmadii, S. lowiae, S. sp. nov., and S. wallichii. The anthesis of S. lowiae, S. sp. nov., and S. wallichii started just after dawn but in S. ahmadii, it began two hours later. Spadix temperatures of the four species increased at the beginning of each of the two successive flowering mornings, corresponding respectively to the pistillate and staminate phases of anthesis. The appendices of S. ahmadii, S. lowiae, and S. sp. nov. underwent the highest temperature increases (average 9.5°C above ambient air) compared to the staminate zone (6.5°C above ambient air); almost no thermogenic activity was recorded in the pistillate zone (0.4°C above ambient air). In inflorescences of S. wallichii, in which the spadix lacks an appendix, the pistillate zone also heated up (2.3°C above ambient air), together with the sterile (2.6°C above ambient air) and the staminate zones (5.2°C above ambient air). Thermogenic patterns varied across species owing to differences in timing of anthesis or spadix structures. The absence of an appendix (sterile floral tissue) in S. wallichii, is not only partially compensated by heat production from the (intermediate) sterile zone but also heat production from the pistillate zone, recorded here for the first time in Tribe Schismatoglottideae.

Advancing frost dates have reduced frost risk among most North American angiosperms since 1980.

In recent decades, the final frost dates of winter have advanced throughout North America, and many angiosperm taxa have simultaneously advanced their flowering times as the climate has warmed. Phenological advancement may reduce plant fitness, as flowering prior to the final frost date of the winter/spring transition may damage flower buds or open flowers, limiting fruit and seed production. The risk of floral exposure to frost in the recent past and in the future, however, also depends on whether the last day of winter frost is advancing more rapidly, or less rapidly, than the date of onset of flowering in response to climate warming. This study presents the first continental-scale assessment of recent changes in frost risk to floral tissues, using digital records of 475,694 herbarium specimens representing 1,653 angiosperm species collected across North America from 1920 to 2015. For most species, among sites from which they have been collected, dates of last frost have advanced much more rapidly than flowering dates. As a result, frost risk has declined in 66% of sampled species. Moreover, exotic species consistently exhibit lower frost risk than native species, primarily because the former occupy warmer habitats where the annual frost-free period begins earlier. While reducing the probability of exposure to frost has clear benefits for the survival of flower buds and flowers, such phenological advancement may disrupt other ecological processes across North America, including pollination, herbivory, and disease transmission.

Micromorphological, histochemical and ultrastructural analysis of flower secretory structures in two species pollinated by flies (Diptera) of Asclepiadoideae Burnett

This micromorphological, chemical and ultrastructural study is a continuation of research conducted on fly-pollinated species. The aim of proposed project is to examine the features of floral secretory tissue of stapeliads (Eudicots, Apocynaceae, Asclepiadoideae) and compare them with previously published Bulbophyllum species (Monocots, Orchidaceae, Epidendroideae). The Echidnopsis cereiformis and Stapelia scitula flowers comprised features that characterize a fly-pollinated syndrome. Secretory activity was observed on the adaxial (upper) surface of flowers of both species, however, the chemical composition of secretion differs between species. In S. scitula it is lipid-rich material, whereas in E. cereiformis it is protein-rich. The ultrastructural studies revealed dense cytoplasm in the epidermis and subepidermal tissue with large nuclei and numerous mitochondria, the profiles of SER and RER, and dictyosomes. Large amounts of secreted material were present on the cuticle surface, similar to the unusual prominent periplasmic space with flocculent secretory material. The most remarkable feature was the presence of a prominent periplasmic space in the epidermal cells of S. scitula. Interestingly, subcuticular spaces have been noted only in a few other species, including three orchids from the section Lepidorhiza. Since Asclepiadaceae and Orchidaceae share other features which developed independently, such as pollen mass coherent in pollinia, presence of a periplasmic space could have also developed as a consequence of pollinators pressure and could be a feature important taxonomically.

Gene silencing of BnaA09.ZEP and BnaC09.ZEP confers orange color in Brassica napus flowers.

Brassica napus is currently cultivated as an important ornamental crop in China. Flower color has attracted much attention in rapeseed genetics and breeding. Here, we characterize an orange-flowered mutant of B. napus that exhibits an altered carotenoid profile in its petals. As revealed by map-based cloning, the change in color from yellow to orange is attributed to the loss of BnaC09.ZEP (zeaxanthin epoxidase) and a 1695-bp deletion in BnaA09.ZEP. HPLC analysis, genetic complementation and CRISPR/Cas9 experiments demonstrated that BnaA09.ZEP and BnaC09.ZEP have similar functions, and the abolishment of both genes led to a substantial increase in lutein content and a sharp decline in violaxanthin content in petals but not leaves. BnaA09.ZEP and BnaC09.ZEP are predominantly expressed in floral tissues, whereas their homologs, BnaA07.ZEP and BnaC07.ZEP, mainly function in leaves, indicating redundancy and tissue-specific diversification of BnaZEP function. Transcriptome analysis in petals revealed differences in the expression of carotenoid and flavonoid biosynthesis-related genes between the mutant and its complementary lines. Flavonoid profiles in the petals of complementary lines were greatly altered compared to the mutant, indicating potential cross-talk between the regulatory networks underlying the carotenoid and flavonoid pathways. Additionally, our results indicate that there is functional compensation by BnaA07.ZEP and BnaC07.ZEP in the absence of BnaA09.ZEP and BnaC09.ZEP. Cloning and characterization of BnaZEPs provide insights into the molecular mechanisms underlying flower pigmentation in B. napus and would facilitate breeding of B. napus varieties with higher ornamental value.

Overexpression of the Raphanus sativus RsMYB1 using the flower-specific promoter (InMYB1) enhances anthocyanin accumulation in flowers of transgenic Petunia and their hybrids

The generation of transgenic floricultural crops for flower color modification requires a transgene that enhances anthocyanin accumulation and a flower-specific promoter with stable expression throughout flowering stage. Here, the anthocyanin regulatory R2R3-MYB transcription factor (TF) RsMYB1 was placed under the control of the stable flower-specific promoter (InMYB1) to enhance anthocyanin accumulation in Petunia hybrida cv. Mirage Rose. RsMYB1 overexpression with the flower-specific promoter enhanced anthocyanin accumulation only in floral tissues via the upregulation of key anthocyanin biosynthetic genes. The target gene introgression to another Petunia hybrida cv. White Hawaiian lacking anthocyanins also changed the flower color from white to intense pink in the F1 hybrids by upregulating the biosynthetic genes. Target gene inheritance in the F2 hybrids also produced diverse flower colors, redder than those of non-inheritance F2 hybrids. RsMYB1 overexpression using the flower-specific promoter (InMYB1) enhanced anthocyanin levels in the petals of transgenic Petunia and its related hybrids. Thus, this system can be used as a promising tool for intensifying the flower color of other commercially important floricultural crops. In addition, the obtained F2MW11 and F2MW12 lines are potential commercial cultivars for the floriculture and landscape industries due to its attractive flower color pattern.

Recovery of Crocins From Floral Tissue of Gardenia jasminoides Ellis.

In this research, a novel source of phytopigment crocins from fully open mature flowers of cape jasmine (Gardenia jasminoides) is introduced. Methanol and deionized water were appropriate solvents for pigment recovery with maximum yields of at least 17% from the floral tissue. Pigment separation by thin layer chromatography also confirmed the presence of the carotenoids, which dissolved well in these high-strength polar solvents, in fruit, flower, and leaf materials. The spectral patterns of the extracts from ultraviolet and nuclear magnetic resonance showed maximum absorption at ~420 nm and the chemical shift values were similar to those of crocetin aglycones (crocins) in the methanol extracts of a commercial source of yellow gardenia (fructus or fruit of Gardenia florida). Chemical compositions were then evaluated using aqueous-phase capillary electrophoresis of the methanol extracts. The methanolic extracts of the flowers and fruit had 11 principal ingredients in common. Among these, crocetin and crocin 2 belong to the crocin group and are known to be the major components of commercial yellow Gardenia. This research not only demonstrates a sustainable means of raw material utilization for natural product recovery, but also encourages a movement toward an edible landscape for the community.

Biomechanical properties of a buzz-pollinated flower.

Approximately half of all bee species use vibrations to remove pollen from plants with diverse floral morphologies. In many buzz-pollinated flowers, these mechanical vibrations generated by bees are transmitted through floral tissues, principally pollen-containing anthers, causing pollen to be ejected from small openings (pores or slits) at the tip of the stamen. Despite the importance of substrate-borne vibrations for both bees and plants, few studies to date have characterized the transmission properties of floral vibrations. In this study, we use contactless laser vibrometry to evaluate the transmission of vibrations in the corolla and anthers of buzz-pollinated flowers of Solanum rostratum, and measure vibrations in three spatial axes. We found that floral vibrations conserve their dominant frequency (300 Hz) as they are transmitted throughout the flower. We also found that vibration amplitude at anthers and petals can be up to greater than 400% higher than input amplitude applied at the receptacle at the base of the flower, and that anthers vibrate with a higher amplitude velocity than petals. Together, these results suggest that vibrations travel differently through floral structures and across different spatial axes. As pollen release is a function of vibration amplitude, we conjecture that bees might benefit from applying vibrations in the axes associated with higher vibration amplification.

Evolutionary trade-offs in the chemical defense of floral and fruit tissues across genus Cornus.

Defense investment in plant reproductive structures is relatively understudied compared to the defense of vegetative organs. Here the evolution of chemical defenses in reproductive structures is examined in light of the optimal defense, apparency, and resource availability hypotheses within the genus Cornus using a phylogenetic comparative approach in relation to phenology and native habitat environmental data. Individuals representing 25 Cornus species were tracked for reproductive phenology over a full growing season at the Arnold Arboretum of Harvard University. Floral, fruit, and leaf tissue was sampled to quantify defensive chemistry as well as fruit nutritional traits relevant to bird dispersal. Native habitat environmental characteristics were estimated using locality data from digitized herbarium records coupled with global soil and climate data sets. The evolution of later flowering was correlated with increased floral tannins, and the evolution of later fruiting was correlated with increased total phenolics. Leaves were found to contain the highest tannin activity, while inflorescences contained the highest total flavonoids. Multiple aspects of fruit defensive chemistry were correlated with fruit nutritional traits. Floral and fruit defensive chemistry were evolutionarily correlated with aspects of native habitat temperature, precipitation, and soil characteristics. Results provide tentative support for the apparency hypothesis with respect to both flower and fruit phenology, while relative concentrations of secondary metabolites across organs provide mixed support for the optimal defense hypothesis. The evolution of reproductive defense with native habitat provides, at best, mixed support for the resource availability hypothesis.