Palm Inflorescences Research Articles

Methyl acetate, a highly volatile floral semiochemical mediating specialized plant-beetle interactions.

Olfactory signaling is key to the reproductive biology of entomophilous palms. Both pollinating and specialized herbivorous insects are attracted to fragrance-emitting palm inflorescences that function as reliable food sources, as well as mating and oviposition sites. In the present study, we characterized the floral scent chemistry of the acuri palm (Attalea phalerata), assessing its role in the attraction of flower-visiting insects associated with this species over its natural distribution range. We sampled insects from staminate inflorescences of A. phalerata (n = 6) at four different sites in the Brazilian Atlantic Forest and Cerrado, and Colombian Amazon basin. Dynamic headspace scent samples of both pistillate and staminate inflorescences of A. phalerata (n = 3♀, 3♂) were collected and analyzed by gas chromatography-mass spectrometry. Methyl acetate, a rare floral scent compound, was identified as the almost exclusive constituent (> 99.8% relative percentage) in all the samples. Flight-interception traps baited with methyl acetate, installed in one of the sites in the Brazilian Cerrado, were attractive to beetles associated with inflorescences of A. phalerata across all four sampling sites (9 spp. in total), including the putative main pollinators (Mystrops spp., Nitidulidae; Andranthobius spp., Curculionidae) and various palm borers (Paratenthras martinsi, Cerambycidae; Parisoschoenus sp.1 and Belopoeus sp.1; Curculionidae). Methyl acetate is highly volatile and we hypothesize its efficacy relies on profuse emission by the inflorescences of A. phalerata, as specialized pollinating insects respond to high concentrations of the attractant, perhaps before odor plumes rapidly disperse. Such a strategy could prove particularly effective in dense populations of A. phalerata.

Antifungal Potential of Phytochemicals against Mauginiella scaettae, the Plant Pathogen Causing Inflorescence Rot of Date Palm.

Date palm (Phoenix dactylifera L.) inflorescence rot caused by Mauginiella scaettae poses a serious threat to date palm in Morocco. The present study aims to determine the antifungal activity of five plant extracts against M. scaettae, including Acacia cyanophylla, Cupressus atlantica, Eucalyptus torquata, Nerium oleander, and Schinus molle and link this effect to their content in phenolics and flavonoids, as well as their antioxidant properties. Plant extracts exhibited significant discrepancies regarding their antifungal activity (p < 0.05). The extracts of E. torquata and C. atlantica had the strongest and dose-dependent manner inhibitory effect against mycelial growth and spore germination. E. torquata and S. molle caused the greatest sporulation reductions of about 88.05% and 36.11%, respectively. In addition, there were significant differences among the examined plant extracts with respect to their total polyphenols (14.52–76.68 mg GAE/g DW), flavonoids (8.75–57.78 g RE/100 g DW), and antioxidant properties as measured by TEAC (74.77–391.23 mmol TE/g DW) and FRAP assays (87.18–474.04 mmol TE/g DW). Strong correlations were found between phenolic compounds and antioxidant activity suggesting that polyphenols play a key role in the observed antioxidant and antifungal activities.

Thidiazuron-induced direct organogenesis from immature inflorescence of three date palm cultivars

BackgroundInflorescence explants of date palm proved to be a promising tool for micropropagation of elite cultivars or rare males and females as organogenesis and somatic embryogenesis could be achieved. These plant materials are abundantly available every year and can be used as cheap and potent explants. Nevertheless, many difficulties could be faced in this protocol according to selection of the spathe size and age, media components, growth regulators, etc. The aim of this study was to determine the influence of various cytokinins on direct organs induction of three date palm cultivars (Selmi, Barhee, and Medjool) from immature inflorescence. An additional objective of this study was to investigate the effect of cytokinins and auxins on growth and development of Medjool cultivar. ResultsVarious combinations of cytokinins were investigated on three date palm inflorescences as N6-(2-isopentenyl) adenine (2iP), kinetin, benzyleadenine (BA), and thidiazuron (N-phenyl-N′-1,2,3-thidiazol-5-yl urea) (TDZ). TDZ alone or in combination with BA proved to be superior for direct organogenesis in all three cultivars so that another combination of TDZ with BA was conducted. Results showed that moderate concentration of BA, with TDZ, gave superior response. Medjool cultivar response surpassed other two cultivars that made the possibility to conduct some growth regulators treatments on its multiplication and regeneration. TDZ at 0.5 + BA at 1.0 mg/l without activated charcoal seemed to enhance multiplication rate. Medium containing 0.5 mg/l of both naphthaleneacetic acid and indole butyric acid in addition to 1.0 mg/l indole acetic acid appeared to be more suitable for rooting stage of Medjool shootlets. ConclusionIn this study, we created an innovation sequence of growth regulators included in nutrient media for date palm direct organogenesis from inflorescence. Organogenesis has been accelerated from immature inflorescence explants and developed to healthy plantlets which acclimatized in greenhouse.

Life cycle and larval growth of Dynamis borassi (Coleoptera: Dryophthoridae), an emerging pest to the peach palm

Dynamis borassi Fabricius (Coleoptera: Dryophthoridae) is widely distributed in South America and is an economic pest in commercially important palms (Arecaceae). In Colombia, peach palm production is of socio-economic importance in the Pacific region but has decreased dramatically due to a weevil complex that attacks the top of the palm. Dynamis borassi is the principal cause of this damage. Despite its importance, the biology of this species is unknown. A rigorous study of life cycle duration, as well as each stage of development, is key to future ecological and behavioural studies and essential in the design of comprehensive pest management plans. We report details of the life history of this pest in a laboratory colony. Life cycle and the larval growth were studied under controlled laboratory conditions (27 ± 1 °C and 75 ± 5% RH) using two artificial diets: Diet 1 without peach palm inflorescences and Diet 2 with 100 g of inflorescences. The egg stage lasted 3.5 ± 0.1 days, the larval stage 165.5 ± 4.7 days for Diet 1 and 153.8 ± 3.9 days for Diet 2, and the pupal stage 37 ± 1.7 days for Diet 1 and 39.7 ± 1.2 days for Diet 2. Twelve instars were observed. The instar when pupation took place varied from instar VII to XII. The weight gain curve had four growth phases with both diets. Each diet produced a different life cycle duration and growth rate. No significant differences were found in the life cycle between the diets.

In Vitro Induction of Callus and Flowers in Immature Oil Palm Inflorescences

This work aimed to investigate the effects of different combinations of auxin (0, 225 and 450 µM Picloram) and Murashige and Skoog salts (50% and 100% MS salt concentrations, respectively named as ½ MS and MS) in mediate the induction of callus and flowers from immature inflorescences (developmental stages I-9, I-12 and I-15) of the oil palm BRS – Manicoré hybrid. In I-9 inflorescence explants, the rate of callus induction was 17% higher in ½ MS than in MS; while in both I-12 and I-15 inflorescence explants, callus induction was over than 95% regardless of the MS salt concentration. The higher rate of callus induction in I-9 inflorescences was mediated by 450 µM Picloram, while the callus induction rates for either I-12 or I-15 inflorescences were higher than 92% regardless of Picloram concentration. Floral induction was lower in I-9 inflorescence explants (45% floral induction rate) than in both I-12 and I-15 inflorescence explants (floral induction rate higher than 90%). Our results suggest that Picloram (450 µM) and MS salts concentrations (½ MS) led to the highest rates of calluses and flowers induction in younger inflorescence explants (I-9); however, the medium composition is indifferent on callus and flower induction in I-12 and I-15 inflorescences.

Palms and pollen beetles: two new anthophilous beetle species of Meligethinus from Mozambique (Coleoptera: Nitidulidae: Meligethinae).

The genus Meligethinus Grouvelle, 1906 represents a small group of pollen beetles, including some twenty species distributed from southern Palaearctic areas to northern Oriental and Afrotropical regions. All constituent species appear to be strictly associated as larvae and adults to male inflorescences of palms (Monocots: Arecaceae). Two new species of this genus (Meligethinus mondlanei sp. nov. and M. hamerlae sp. nov.) were recently discovered in southern Mozambique, and are described herein. Both are associated as larvae with male inflorescences of the widespread eastern African palm Phoenix reclinata Jacq. The two new species are compared with related taxa from central Africa. Additionally, the presence of additional species of the same genus in southern Mozambique is reported, and the local associations of several Meligethinus species are discussed.

In vitro response of date palm (Phoenix dactylifera L.) inflorescence explants to high 2iP and 2,4-D concentrations

One of the major problems related to the implementation of date palm crops in Brazil is propagation. Therefore, the aim of this study was to evaluate the possibility of using tissue culture technique for the in vitro propagation of this species. Hence, the effect of 2iP and 2,4-D on the in vitro response of date palm inflorescence tissues, related to floral bud swelling, callusing, and rhizogenesis, was evaluated. The absence of 2,4-D was more detrimental to the in vitro response of inflorescence bud explants than absence of 2iP. In treatments without addition of 2,4-D to the culture medium, explants did not have swelling, callus or root formation. The treatment containing 150 mg/L 2,4-D in the presence of 1.5 mg/L 2iP initiated explant swelling, and treatments with either 100 mg/L or 150 mg/L 2,4-D, combined with 3.0 mg/L 2iP, were also efficient in stimulating in vitro swelling of inflorescence buds. Rhizogenesis was induced at the highest concentrations of 2,4-D (100 and 150 mg/L), combined with 4.5 mg/L 2iP, and was visually more evident in the treatment containing 150 mg/L 2,4-D + 4.5 mg/L 2iP. These results suggest that even higher concentrations of these two reagents might be efficient in the micropropagation of new existing date palm genotypes in the Submedium São Francisco River Valley.

Maastrichtian Palynoflora from Deccan Volcanic Associated Sediments of Mahurzari, Nagpur District, Maharashtra: Age and Paleoenvironment with Comments on Megaflora

Palynological study of intertrappean sediments of Mahurzari in Nagpur district, Maharashtra, a known megaflora rich locality, has indicated presence of diverse pollen and spore assemblage. The palynoassemblage includes six genera and six species of pteridophytes dominated by Cyathidites and Lygodiumsporites and four genera and four species of angiosperms. The presence of palynomorphs such as Azolla cretacea, Gabonisporis vigourouxii, Aquilapollenites bengalensis and Farabeipollis suggests a Maastrichtian age. Megafloral remains such as flowers and fruits of Sahnipushpam, fruits of Viracarpon, Indovitis, Baccatocarpon, a coconut like fruit and Palmocarpon, the palm inflorescence Mahurzaristrobus and many fossils wood of dicot and monocot plants are also known from this locality. The recorded flora suggests prevalence of tropical evergreen floristic conditions at the time of deposition of the intertrappean paleolake sediments having volcano-clastic inputs.

DATE PALM AND DATE PALM INFLORESCENCES IN THE LATE URUK PERIOD (C. 3300 B.C.): BOTANY AND ARCHAIC SCRIPT

The earliest evidence suggesting the human utilisation of wild date palm fruits in the Near East is dated to the sixth and fifth millennia B.C. Despite the lack of archaeological data, it is commonly believed that at the end of the Late Uruk period (c. 3300–3100 B.C.) the Sumerians established the first date palm plantations. Nevertheless, this belief has never been well-proven by any scientific data, which makes this issue open to debate. This article points to the images of the date palm known from the pictographic script from Uruk as an important source of botanical data—a concept which has never been discussed in the literature—and elaborates on the phenotypic traits of the Phoenix dactylifera L. discernible there. It aims to establish the level and condition of horticultural knowledge of the cultivators of the date palm tree in the late fourth millennium B.C.Many of the botanical traits found on the date palm pictographs are noteworthy, especially where the morphology of the crown, trunk, and root zone are concerned. Most importantly, the identification of pictographs representing date palm inflorescences prompts us to the conclusion that the Sumerians discovered the dioecious nature of the Phoenix dactylifera L., selecting the staminate inflorescences to pollinate female trees by at least c. 3300 B.C. The discovery of this method of artificial fertilization was a turning point in Mesopotamian agriculture since it enabled farmers to obtain a better crop while economizing on space and labour, constituting the beginning of the date palm plantations that are still such a feature of present-day Iraq.

Chemical ecology of Cyclocephala forsteri (Melolonthidae), a threat to macauba oil palm cultivars (Acrocomia aculeata, Arecaceae)

AbstractThe environmental unsustainability of African oil palm crops is a growing worldwide concern, and the macauba palm in tropical Southern America surges as the most viable substitute for the production of first‐generation biodiesel as a renewable fuel. Large‐scale cultivation of the macauba palm, however, is bound to suffer a major setback due to the fast emergence of a florivorous pest threat, Cyclocephala forsteri, a scarab beetle species that can severely reduce fruit yield. Like other congenerics, female and male C. forsteri are night‐foraging and driven in large numbers to macauba palm inflorescences by specific volatile organic compounds. In the present study, we assessed the kairomonal cues involved in this plant–florivore interaction and their potential application in selective pest management strategies. Headspace samples of the floral fragrance of macauba palms at our study site in Central Brazil were largely dominated by 4‐methylanisole (&gt;97% relative amount), which along with the minor constituents 2‐isopropyl‐3‐methoxypyrazine and 2‐sec‐butyl‐3‐methoxypyrazine triggered electroantennographic responses from both female and male C. forsteri. Field behavioural assays evidenced that beetles of this species were exclusively attracted to scented traps baited with 4‐methylanisole. Increased total scent discharge attained with an ultrasonic piezoelectric diffuser has positively influenced attractiveness efficiency of the trapping setup. 4‐Methylanisole is hereby identified as yet another volatile kairomone involved in highly selective attraction of potential pest florivorous cyclocephaline scarabs associated with economically exploitable palms and should be viewed as a key element in short‐term integrated management plans for the cultivation of the macauba palm in South America.

Ancognatha vulgaris (Melolonthidae, Cyclocephalini): a specialized pollen-feeding scarab associated with wax palms (Ceroxylon spp., Arecaceae) in Andean cloud forests of Colombia

With 22 species, Ancognatha is the fourth most species-rich genus of Neotropical cyclocephaline scarabs (Melolonthidae, Cyclocephalini), an important group of anthophilous insects associated with palms (Arecaceae). Unlike other members of the tribe, which predominantly inhabit low-altitude ecosystems, Ancognatha spp. are most common in montane areas, at elevations of 1500 to over 4000 m a.s.l. In the cloud forests of the Andes of Colombia, we investigated the association between Ancognatha vulgaris and seven species of wax palms (Ceroxylon spp.) from 2009 to 2013. Male and female A. vulgaris can be characterized as specialized florivores recovered in abundances of up to 40 individuals at both male and female inflorescences of all studied species of wax palms, which they also used for shelter and as aggregation sites for mating. The night-active beetles preferably fed on the pollen released in high quantities by staminate flowers of male inflorescences, but were also observed gnawing on the pistillate flowers of female inflorescences. We hypothesize that wax palm inflorescences are a key resource for the maintenance of populations of A. vulgaris under the extreme environmental conditions of Andean montane ecosystems, an assumption supported by their overlapping biogeographical distributions.

Probiotic Properties of Lactic Acid Bacteria Isolated From Neera: A Naturally Fermenting Coconut Palm Nectar.

Probiotic bacteria were isolated from different traditional fermented foods as there are several such foods that are not well explored for their probiotic activities. Hence, the present study was conducted to find the potential of lactic acid bacteria (LAB) as probiotics that were isolated from the sap extract of the coconut palm inflorescence – Neera, which is a naturally fermented drink consumed in various regions of India. A total of 75 isolates were selected from the Neera samples collected aseptically in the early morning (before sunrise). These isolates were initially screened for cultural, microscopic, and biochemical characteristics. The initial screening yielded 40 Gram-positive, catalase-negative isolates that were further subjected to acid – bile tolerance with resistance to phenol. Among 40 isolates, 16 survived screening using analysis of cell surface hydrophobicity, auto aggregation with adhesion to epithelial cells, and gastric–pancreatic digestion for gastrointestinal colonization. The isolates were also assessed for antimicrobial, antibiotic sensitivity, and anti-oxidative potential. The safety of these isolates was evaluated by their hemolytic and deoxyribonuclease (DNase) activities. Based on these results, seven isolates with the best probiotic attributes were selected and presented in this study. These LAB isolates, with 51.91–70.34% survival at low pH, proved their resistance to gastric conditions. The cell surface hydrophobicity of 50.32–77.8% and auto aggregation of 51.02–78.95% represented the adhesion properties of these isolates. All the seven isolates exhibited good antibacterial and antifungal activity, showing hydroxyl-scavenging activity of 32.86–77.87%. The results proved that LAB isolated from Neera exhibited promising probiotic properties and seem favorable for use in functional fermented foods as preservatives.

Association of Pollinators of Different Species of Oil Palm with the Metabolic Profiling of Volatile Organic Compounds.

The development of studies on emissions of volatile organic compounds (VOCs) by inflorescence of oil palms deserves a special attention regarding the importance to reproduction success and for increase of production. This study aimed to evaluate metabolic profiling of VOCs expelled by male and female inflorescences of different oil palm species (African oil palm, Amazonian Caiaué and the interspecific hybrid BRS-Manicoré), associating the composition variability with main pollinators to improve the comprehension of the plant-insect relationship. The phenylpropanoids, terpenoids and the aliphatic hydrocarbons were predominant classes detected in inflorescences of oil palms and the major compound was estragole. This result may be correlated with attraction of Elaidobius pollinators, since these insects were not attracted by Caiaué, which emitted estragole only in trace amounts. However, Caiaué and the hybrid species were visited by other native species whose frequencies were low and their success as pollinators could not be expected.

Effect of processing aid on the chemical composition and metagenomics of fermented African oil bean seed (Pentaclethra macrophylla, Benth)

Oil palm inflorescence ash (FMA) has been used in post-harvest processing and preservation of food crops. In this study effect of oil palm inflorescence ash as a processing aid on the chemical composition and metagenomics of fermented African oil bean seed (Pentaclethra macrophylla, Benth) was investigated. The result showed that the African oil bean seeds sample fermented with FMA had higher total amino acid (TAA) content (88.48 g/100 g crude protein (cp)) and better protein quality compared to the sample fermented without the ash (NFM) (81.04 g/100 g cp) and the unfermented (UFM) sample (8.07 g/100 g cp). The FMA had lower residual anti-nutritional factors and total saturated fatty acid (4.07%) hence has better dietary value than the NFM and UFM samples. New aromatic volatile compounds were also produced in the FMA which further improved its sensory quality compared to the NFM and UFM samples. The metagenomic study revealed that FMA had fewer spoilage bacteria but higher fermentative yeasts than the NFM. Thus the findings of the current study provide evidence that African oil bean seeds fermented with oil palm inflorescence ash have better chemical and microbial composition than the one processed without the oil palm ash.

Transcriptome analysis of oil palm inflorescences revealed candidate genes for an auxin signaling pathway involved in parthenocarpy.

Oil palm parthenocarpic fruits, which are produced without fertilization, can be targeted to increase oil content because the majority of the fruit is occupied by mesocarp, the part in which palm oil is stored. Consequently, gaining an understanding of the parthenocarpic mechanism would be instrumental for producing parthenocarpic oil palm. This study aims to determine effects of auxin treatment and analyze differentially expressed genes in oil palm pistils at the pollination/anthesis stage, using an RNA sequencing (RNA seq) approach. The auxin treatment caused 100% parthenocarpy when auxin was sprayed before stigmas opened. The parthenocarpy decreased to 55%, 8% and 5% when the auxin was sprayed 1, 2 and 3 days after the opening of stigmas, respectively. Oil palm plants used for RNA seq were plants untreated with auxin as controls and auxin-treated plants on the day before pollination and 1 day after pollination. The number of raw reads ranged from 8,425,859 to 11,811,166 reads, with an average size ranging from 99 to 137 base pairs (bp). When compared with the oil palm transcriptome, the mapped reads ranged from 8,179,948 to 11,320,799 reads, representing 95.85–98.01% of the oil palm matching. Based on five comparisons between RNA seq of treatments and controls, and confirmation using reverse transcription polymerase chain reaction and quantitative real-time RT-PCR expression, five candidate genes, including probable indole-3-acetic acid (IAA)-amido synthetase GH3.8 (EgGH3.8), IAA-amido synthetase GH3.1 (EgGH3.1), IAA induced ARG7 like (EgARG7), tryptophan amino transferase-related protein 3-like (EgTAA3) and flavin-containing monooxygenase 1 (EgFMO1), were differentially expressed between auxin-treated and untreated samples. This evidence suggests a pathway of parthenocarpic fruit development at the beginning of fruit development. However, more research is needed to identify which genes are definitely involved in parthenocarpy.

Populasi Elaeidobius kamerunicus Faust (Coleoptera: Curculionidae) pada beberapa umur tanaman kelapa sawit

Kumbang Elaeidobius kamerunicus Faust merupakan serangga polinator kelapa sawit yang hidup pada bunga jantan dan mengunjungi bunga betina untuk melakukan penyerbukan karena ketertarikan terhadap senyawa volatil yang dikeluarkan. Kuantitas fruit set kelapa sawit yang dihasilkan berhubungan dengan populasi E. kamerunicus pada suatu lahan. Penelitian ini bertujuan untuk mempelajari pengaruh umur tanaman kelapa sawit terhadap populasi kumbang E. kamerunicus. Penelitian dilakukan di perkebunan kelapa sawit yang terletak di Pangkalan Lada, Kotawaringin Barat, Kalimantan Tengah. Metode penelitian yang digunakan adalah berupa penghitungan populasi E. kamerunicus pada bunga jantan dan pemasangan sticky trap pada bunga betina. Plot pengamatan berukuran 7000 m2 (100 pohon) dengan variasi umur tanaman kelapa sawit, yaitu 6, 10, dan 16 tahun. Setiap plot dihitung jumlah bunga jantan dan betina yang mekar dan ditentukan beberapa bunga untuk pengukuran populasi E. kamerunicus yang dilakukan setiap bulan selama tiga bulan pengamatan. Hasil penelitian menunjukkan bahwa umur tanaman kelapa sawit berpengaruh terhadap populasi E. kamerunicus pada bunga jantan tapi tidak pada bunga betina. Semakin tua umur kelapa sawit, populasi E. kamerunicus pada bunga jantan semakin meningkat. Rasio jenis kelamin E. kamerunicus yang ditemukan pada bunga jantan dan betina kelapa sawit cenderung bias betina. Berdasarkan perbandingan populasi E. kamerunicus pada bunga jantan dan betina pada setiap plot diperoleh bahwa nilai kunjungan E. kamerunicus paling tinggi ditemukan pada umur kelapa sawit muda. Sebagai kesimpulan, pertambahan umur kelapa sawit mempengaruhi peningkatan populasi E. kamerunicus pada bunga jantan tapi persentase kunjungan ke bunga betina menjadi semakin menurun.

Isolation and characterisation of oil palm LEAFY transcripts

ABSTRACTLEAFY (LFY) is an important regulator of plant's reproductive system, regulating the transition from vegetative growth to flowering, and also acts as an upstream regulator of floral homeotic MADS-box genes in Arabidopsis. Owing to its importance in flower development, oil palm LFY transcripts were isolated and the expression pattern was characterised to elucidate the role of LFY in oil palm. In addition, the gene expression pattern was analysed to determine a possible correlation of LFY to a type of floral abnormality in clonal palms termed mantling. In this study, three LFY transcripts were isolated from oil palm inflorescence tissue. The isolated cDNAs, OpLFY1, OpLFY2 and its splice variant, OpLFY2v were predicted to encode proteins each consisting of 430, 451 and 181 amino acids, respectively. OpLFY1 and OpLFY2 share 90% and 94% amino acid sequence identity to two different LFYs from Phoenix dactylifera, respectively. OpLFY1 was localised in all floral organ primordia. Quantitative polymerase chain reaction (qPCR) analysis revealed that OpLFY genes are expressed in shoot apical meristem and inflorescence tissues with the highest expression level. The expression of the OpLFY1 gene was significantly lower in stage 1 of inflorescence development in mantled palms compared with that of normal inflorescences, suggesting possible association of the gene with this somaclonal variation.

Metarhizium anisopliae against Prosoestus Spp., Pests of Female Oil Palm Inflorescences: Preliminary Laboratory Tests

Metarhizium anisopliae against Prosoestus Spp., Pests of Female Oil Palm Inflorescences: Preliminary Laboratory Tests

2-Alkyl-3-methoxypyrazines are potent attractants of florivorous scarabs (Melolonthidae, Cyclocephalini) associated with economically exploitable Neotropical palms (Arecaceae).

2-Alkyl-3-methoxypyrazines (MPs) are naturally occurring aromatic compounds involved in insect chemical communication as both pheromones and allelochemicals. Although rarely characterized in floral scents, they have been identified as major constituents in headspace samples from palm inflorescences and evidence pointed towards their function as attractive cues for scent-oriented pollinators, as well as florivores. In this study, we investigated the occurrence of MPs in economically exploitable palms belonging to Acrocomia and Attalea through headspace floral scent analysis and assessed their role in the selective attraction of flower-feeding cyclocephaline scarabs (Melolonthidae, Cyclocephalini) in field bioassays conducted in Brazil and Colombia. Three different MPs were identified among floral headspace samples of Acrocomia aculeata, Acr. intumescens, Attalea butyracea and Att. insignis: 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP) and 2-(sec-butyl)-3-methoxypyrazine (SBMP). Their combined estimated total scent emissions per inflorescence ranged from 246 μg h-1 to 6.2 mg h-1 . Scented traps, individually baited with either IPMP or SBMP, resulted in species-selective and high yield captures of Cyclocephala amazona and C. distincta, known florivores associated with over 20 different species of Neotropical palms. The identification of MPs as potent kairomones could prove instrumental in integrated pest management plans for these insects in emerging oil-yielding crops in South America, including those of the wine palm (Att. butyracea) and macaw palms (Acrocomia spp.). © 2018 Society of Chemical Industry.

First reported case of spontaneous hermaphrodism in female date palm (Phoenix dactylifera L.), cv ‘Alligue’

ABSTRACTThe date palm (Phoenix dactylifera L.) is dioecious with male flowers deficient in functional gynoecium and female flowers deficient in functional androecium borne on separate palms. The presence of male and female flowers on the same plant, a phenomenon known as monoecy, is unusual in male date palms.This study reports for the first time on hermaphrodite (bisexual) flowers borne by two female date palms, ‘Alligue’, that were found growing in an open field in Degache, southern Tunisia. The observations on these two female palms were compared with hermaphrodite male date palms growing in the same location. Hermaphrodite female date palm inflorescence branches bear female flowers predominantly near their base, in contrast to the hermaphrodite flowers that are found primarily toward their upper part. The position of the hermaphrodite flowers in hermaphrodite male date palms is reversed: inflorescence branches bear male flowers toward the upper part while the hermaphrodite flowers are found at the base. Histological examination of female hermaphrodite flowers revealed that they had three carpels and 1–6 stamens. Hermaphrodite flowers on male plants were usually also composed of three carpels of variable size, and six stamens. Hermaphrodite flowers on both female and male palm trees turn generally into parthenocarpic fruits. The present data support the theory that dioecious plants are derived from a common hermaphrodite ancestor. Floral hermaphroditism in date palm should be investigated in relation to the in planta self-fertilization process to identify sex markers and genes that control sex organ development.