Evaluation of morphological traits of flowers and crossing possibility of haskap (Lonicera L) cultivars depending on their origin

BACKGROUND: Haskap (Lonicera L.) is as a new perspective berry species for growing in temperate region climate. According to nowadays knowledge haskap is absolutely self-sterile species hence the studies on pollination mode are required. OBJECTIVE: The aim was to evaluate new haskap cultivars of Canadian and Russian origin in terms of their matching for cross-pollination. METHODS: The overlapping of flowering time of cultivars for mutual cross pollination was selected. The effectiveness of pollination was assessed: in terms of pollen tube overgrowth through the pistil tissue and the quality of set fruit. RESULTS: The Russian cultivars bloomed much earlier than the Canadian cultivars. The stigma is most receptive in the freshly open flower stage and directly after the anther burst. The minimum qualitatively acceptable weight of a berry is 1 g, which corresponds to the formation of about 6 seeds in the fruit. The most compatible pairs of cultivars were: ‘Aurora’בJugana’, ‘Aurora’בSinij Utes’ and ‘Aurora’בVostorg’. CONCLUSION: The Russian cultivars bloomed much earlier than the Canadian cultivars, the stigma is most receptive in the freshly open flower, minimum qualitatively acceptable weight of berry is 1 g (what represents 6 seeds in fruit), best mutual pollinating cultivars are the cultivars within the same breeding group (Russian x Russian and Canadian x Canadian)

Temperature-responded biological fitness of carbendazim-resistance Fusarium graminearum mutants conferring the F167Y, E198K and E198L substitutions

Understanding the effects of temperature on Fusarium graminearum infection can provide the theoretical guidance for chemical control of Fusarium head blight (FHB)．Here, we evaluated the effects of various temperatures on biological fitness development of wild-type sensitive strain 2021 and carbendazim-resistance mutants conferring β2-tubulin substitutions F167Y, E198K and E198L. The results showed that mycelial growth and conidiation of four strains increased with the increase of the temperature between 10°C and 25°C. Conidia of F167Y displayed strong adaptability to low temperature. The virulence of the four strains was largely similar at the same temperature, showing an upward trend between 10°C and 25°C. At 10°C, the hyphal growth of all strains was significantly inhibited, and metabolism slowed down and the accumulation of secondary metabolites decreased. Subsequently, the production of deoxynivalenol (DON) and its intermediate, pyruvate and aurofusarin decreased at low temperature, and the expression of DON biosynthesis-related genes Tri5, FgPK and AUR decreased accordingly. At the same temperature, the aurofusarin production of the strains F167Y and E198K was higher than that of strains 2021 and E198L. The contents of DON and pyruvic acid in carbendazim-resistance mutants were higher than that of the wild-type strain 2021. The sensitivity of four strains to different fungicides changed at various temperatures. The sensitivity to most fungicides increased with the temperature decreasing. The carbendazim-resistance mutants appeared positive cross-resistance with other benzimidazoles. But there was no cross-resistance to pyraclostrobin and azoles. These results would direct us to use fungicide preventing the infection of F. graminearum with changeable atmospheric temperature at wheat flower stage.

Micromorphology and anatomy of the flower of Zephyranthes candida (Amaryllidaceae)

The use of morphological features of flowers in the taxonomy of plants is becoming increasingly important. The structure of the Zephyranthes candida (Lindl.) Herb. flowers on permanent cross-sectional and longitudinal sections was studied using a light microscope. The genus Zephyranthes belongs to the subtribe Hippeastrinae Walp. tribe Hippeastreae Sweet., family Amaryllidaceae s.l. Microscopic studies of the flower are considered as a tool to identify hitherto unknown structural adaptations of plants to specialized pollination methods and to elucidate the first stages of fruit morphogenesis, as many features of the fruit appear at the flower stage. The morphometric parameters, morphology, anatomy, and vascular anatomy of the ovary were described by using the flower’s transverse sections. Ten flowers of Z. candida were sectioned using standard methods of Paraplast embedding and serial sectioning at 20 μm thickness. Sections were stained with Safranin and Astra Blau and mounted in Eukitt. It was found that in the studied species the tepals have multi-bundle traces of 10–12 leading bundles. We consider the gynoecium of the studied species to be eusincarpous. The vascular system of the inferior ovary consists of three dorsal and three septal bundles, paired ventral bundles of carpels, which form ovule traces. For the first time, the presence of the following gynoecium zones was detected: a synascidiate structural zone with a height of about 360 μm and a fertile symplicate structural zone with a height of about 1560 μm and a hemisymplicate zone of 480 μm. Septal nectaries appear in the hemisymplicate zone and open with nectary split at the base of the style, the total height of the septal nectary is 760 μm. The ovary roof is 280 μm. Bifurcated dorsal and septal bundles of carpels have been identified, which can be considered as adaptations of the early stages of fruit morphogenesis to opening. Anatomical features of the ovary of Z. candida are numerous vascular bundles in the pericarpium, non-lignified endocarp at the flower stage, we consider as adaptations to the formation of juicy fruit. New data on the anatomical structure of the flower are a significant addition to the information on antecological and post-anthetic features of the studied species. Also, these data can be used in the construction of parsimony branches of the family Amaryllidaceae.

Quantitative analysis of auxin metabolites in lychee flowers

ABSTRACT 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.

Young capitulum as important explant in in vitro mass propagation of gerbera (Gerbera jamesonii)

A new route of in vitro propagation of gerbera selected clones was successfully established using young capitula in tight buds and buds that were started to unfold stage as explant source. The one-fourth pieces of young capitula of tight flower stage and half-strength MS medium containing 0.25 mg/l BAP was the suitable for initiation and produced higher number of shoots per explant up to 3.8 shoots. The results were improved by culturing the one-fourth piece of 01.092 capitulums on MS medium fortified by 0.2 mg/l BAP and 0.02 mg/l NAA producing the highest shoot formation up to 8.5 shoots per explant with 28.7 leaves per explant and 2.1 cm leaf length. High multiple shoots were determined in third to fourth subculture periods and reduced thereafter with high multiplication rate noted on 01.092 clone. Shoots were easily rooted on half-strength MS medium supplemented with 2 g/l activated charcoal. Plantlets were transferred to ex vitro condition with 96.4% survivability of 03.045 clone using Cycas rumphii bulk and cocopeat (1:1, v/v) under spraying 1 g/l Growmore (32N:10P:10K) solution once week periodically. The route has high potential applied in qualified plantlet production for other Gerbera’s due to high shoots produced up to 35 shoots per whole young capitulum used.

Identification and Molecular Characterization of Geranyl Diphosphate Synthase (GPPS) Genes in Wintersweet Flower

Geranyl diphosphate synthase (GPPS) is a plastid localized enzyme that catalyzes the biosynthesis of Geranyl diphosphate (GPP), which is a universal precursor of monoterpenes. Wintersweet (Chimonanthus praecox L.), a famous deciduous flowering shrub with a strong floral scent character, could have GPPS-like homologs that are involved in monoterpenes biosynthesis, but it remains unclear. In the present study, five full-length GPPS and geranylgeranyl diphosphate synthases (GGPPS) genes were identified in the wintersweet transcriptome database. The isolated cDNAs showed high protein sequence similarity with the other plants GPPS and GGPPS. The phylogenetic analysis further classified these cDNAs into four distinct clades, representing heterodimeric GPPS small subunits (SSU1 and SSU2), homodimeric GPPS, and GGPPS. Analysis of temporal expression revealed that all genes have the highest transcript level at the full-open flower stage. From tissue-specific expression analysis, CpGPPS.SSU1 and CpGGPPS1 were predominantly expressed in petal and flower, whereas CpGPPS.SSU2, GPPS, and GGPPS2 showed a constitutive expression. Additionally, the subcellular localization assay identified the chloroplast localization of SSUs and GGPPSs proteins, and the yeast two-hybrid assay showed that both CpGPPS.SSU1 and CpGPPS.SSU2 can interact with the GGPPS proteins. Taken together, these preliminary results suggest that the heterodimeric GPPS can regulate floral scent biosynthesis in wintersweet flower.

Hormonal Regulation of Early Fruit Development in European Pear (Pyrus communis cv. ‘Conference’)

European pear requires inter-cultivar cross-pollination by insects to develop fertilized fruits. However, some European pear cultivars such as ‘Conference’ naturally produce parthenocarpic seedless fruits. To better understand the hormonal regulation of fruit set and early fruit development in this European pear cultivar, the phytohormone and polyamine profiles in ‘Conference’ flowers and fruits resulting from both fertilization and parthenocarpic processes were analyzed. The expression of genes involved in phytohormone metabolism and signaling were also investigated. Phytohormone profiles differed more at flower stage 3 days after treatment than in 15 day- and 30-day-old fruits in response to fertilization and parthenocarpy. An increase in auxins, abscisic acid, ethylene precursor, and spermine, and a decrease in putrescine were recorded in the fertilized flowers as compared to the parthenocarpic flowers. Fertilization also upregulated genes involved in gibberellin synthesis and down-regulated genes involved in gibberellin catabolism although the total gibberellin content was not modified. Moreover, exogenous gibberellin (GA3, GA4/7) and cytokinin (6BA) applications did not increase parthenocarpic induction in ‘Conference’ as observed in other European and Asian pear cultivars. We hypothesize that the intrinsic parthenocarpy of ‘Conference’ could be related to a high gibberellin level in the flowers explaining why exogenous gibberellin application did not increase parthenocarpy as observed in other pear cultivars and species.

Managing cabbage seedpod weevils (Coleoptera: Curculionidae) in canola (Brassicaceae) – are Lygus (Hemiptera: Miridae) affected?

Cabbage seedpod weevil (Ceutorhynchus obstrictus Marsham; Coleoptera: Curculionidae) and Lygus Hahn (Hemiptera: Miridae) species are part of the late season insect pest complex of canola (Brassica Linnaeus; Brassicacea) in the southern prairies of Canada. From 2010 to 2013, large strips in 73 commercial fields were studied in southern Alberta to validate action thresholds for cabbage seedpod weevil and assess the impact of insecticide spraying at the early flower stage for cabbage seedpod weevils on abundance of Lygus at the pod stage. Only fields planted in April accumulated the damaging populations of cabbage seedpod weevils, such that the application of an insecticide resulted in significant yield protection. The economic injury level for the cabbage seedpod weevil was calculated at 20 cabbage seedpod weevils per 10 sweeps, but an action threshold of 25–40 is recommended because sampling mainly occurs along the edge where cabbage seedpod weevils are initially concentrated. At the pod stage, Lygus were lower in strips sprayed with insecticides at the early flower stage than in those not sprayed, but the differences were not statistically significant. Furthermore, Lygus were generally below economically damaging levels in early seeded fields. Therefore, there is no benefit of spraying early seeded fields to attempt to prevent Lygus outbreaks when cabbage seedpod weevils are below thresholds because Lygus may pose a risk only in fields planted later in the season.

Floral Scent Emission from Nectaries in the Adaxial Side of the Innermost and Middle Petals in Chimonanthus praecox

Wintersweet (Chimonanthus praecox) is a well-known traditional fragrant plant and a winter-flowering deciduous shrub that originated in China. The five different developmental stages of wintersweet, namely, flower-bud period (FB), displayed petal stage (DP), open flower stage (OF), later blooming period (LB), and wilting period (WP) were studied using a scanning electron microscope (SEM) to determine the distribution characteristics of aroma-emitting nectaries. Results showed that the floral scent was probably emitted from nectaries distributed on the adaxial side of the innermost and middle petals, but almost none on the abaxial side. The nectaries in different developmental periods on the petals differ in numbers, sizes, and characteristics. Although the distribution of nectaries on different rounds of petals showed a diverse pattern at the same developmental periods, that of the nectaries on the same round of petals showed some of regularity. The nectary is concentrated on the adaxial side of the petals, especially in the region near the axis of the lower part of the petals. Based on transcriptional sequence and phylogenetic analysis, we report one nectary development related gene CpCRC (CRABS CLAW), and the other four YABBY family genes, CpFIL (FILAMENTOUS FLOWER), CpYABBY2, CpYABBY5-1, and CpYABBY5-2 in C. praecox (accession no. MH718960-MH718964). Quantitative RT-PCR (qRT-PCR) results showed that the expression characteristics of these YABBY family genes were similar to those of 11 floral scent genes, namely, CpSAMT, CpDMAPP, CpIPP, CpGPPS1, CpGPPS2, CpGPP, CpLIS, CpMYR1, CpFPPS, CpTER3, and CpTER5. The expression levels of these genes were generally higher in the lower part of the petals than in the upper halves in different rounds of petals, the highest being in the innermost petals, but the lowest in the outer petals. Relative expression level of CpFIL, CpCRC, CpYABBY5-1, and CpLIS in the innermost and middle petals in OF stages is significant higher than that of in outer petals, respectively. SEM and qRT-PCR results in C. praecox showed that floral scent emission is related to the distribution of nectaries.