Multi-Target Recognition of Bananas and Automatic Positioning for the Inflorescence Axis Cutting Point

Multi-target recognition and positioning using robots in orchards is a challenging task in modern precision agriculture owing to the presence of complex noise disturbance, including wind disturbance, changing illumination, and branch and leaf shading. To obtain the target information for a bud-cutting robotic operation, we employed a modified deep learning algorithm for the fast and precise recognition of banana fruits, inflorescence axes, and flower buds. Thus, the cutting point on the inflorescence axis was identified using an edge detection algorithm and geometric calculation. We proposed a modified YOLOv3 model based on clustering optimization and clarified the influence of front-lighting and backlighting on the model. Image segmentation and denoising were performed to obtain the edge images of the flower buds and inflorescence axes. The spatial geometry model was constructed on this basis. The center of symmetry and centroid were calculated for the edges of the flower buds. The equation for the position of the inflorescence axis was established, and the cutting point was determined. Experimental results showed that the modified YOLOv3 model based on clustering optimization showed excellent performance with good balance between speed and precision both under front-lighting and backlighting conditions. The total pixel positioning error between the calculated and manually determined optimal cutting point in the flower bud was 4 and 5 pixels under the front-lighting and backlighting conditions, respectively. The percentage of images that met the positioning requirements was 93 and 90%, respectively. The results indicate that the new method can satisfy the real-time operating requirements for the banana bud-cutting robot.

Hohenbergia densa (Bromeliaceae), a new species from Rio Grande do Norte, Brazil

We describe a new species from Rio Grande do Norte (Brazil), Hohenbergia densa, that inhabits the dry vegetation of the state. This new species can be recognized by its short and robust habit, differing from other Caatinga-endemic species of the region, that commonly present a broader rosette with a long inflorescence axis. Additionally, we provide illustrations, habit, phenology, a map of occurrence, and a table of morphological comparisons with similar taxa.

Structural diversity of fruits: conceptual reflexions and taxonomic implications / Diversidade estrutural de frutos: reflexões conceituais e implicações taxonômicas

Fruit either originates solely from the ovary or ovary and other floral parts and inflorescence. Besides the ovary itself, the pedicle, bracteoles, receptacle, hypanthium, sepals, petals and inflorescence axis are included in the fruit development. Analysis was made in embedded historesin/paraffin material and sectioned in microtome. In the fruit ontogeny the pericarp either may be non-multiplicative or multiplicative. In the first case, the ovary wall differentiates in pericarp without the installation of meristem. Adaxial, middle or abaxial meristems can be installed in the multiplicative pericarp fruits from the periclinal cell divisions that occur in both the epidermis and the ovary mesophyll. Separation tissue takes place in the carpel margins and midrib in dehiscent fruits or it can remain as residual tissue in indehiscent fruits. Fruit classification is complex, and it may show divergence in nomenclature among fruit specialists. Structural fruit ontogeny can be a useful tool for its classification. Fruit structure has been used as diagnostic character of species, genera and tribes of angiosperms. Hypothesis about fruit evolution indicates that apocarpic fruit with follicles can be a basic evolutionary condition, at least among the sensu lato dicots. The Araucaria angustifolia pine seed is considered here as a fruit with protocarps/spermatocarps.

Verbena officinalis Verbenaceae (Lamiales): a new plant model system for phyllotaxis research

Phyllotactic diversity and developmental transitions between phyllotactic patterns are not fully understood. The plants studied so far, such as Magnolia, Torreya or Abies, are not suitable for experimental work, and the most popular model plant, Arabidopsis thaliana, does not show sufficient phyllotactic variability. It has been found that in common verbena (Verbena officinalis L.), a perennial, cosmopolitan plant, phyllotaxis differs not only between growth phases in primary transitions but also along the indeterminate inflorescence axis in a series of multiple secondary transitions. The latter are no longer associated with the change in lateral organ identity, and the sequence of phyllotactic patterns is puzzling from a theoretical point of view. Data from the experiments in silico, confronted with empirical observations, suggest that secondary transitions might be triggered by the cumulative effect of fluctuations in the continuously decreasing bract primordia size. The most important finding is that the changes in the primary vascular system, associated with phyllotactic transitions, precede those taking place at the apical meristem. This raises the question of the role of the vascular system in determining primordia initiation sites, and possibly challenges the autonomy of the apex. The results of this study highlight the complex relationships between various systems that have to coordinate their growth and differentiation in the developing plant shoot. Common verbena emerges from this research as a plant that may become a new model suitable for further studies on the causes of phyllotactic transitions.

Habenaria diphylla (Nimmo) Dalzell (Orchidaceae), new record for the flora of Vietnam

Habenaria diphylla (Nimmo) Dalzell is reported for the first time as a new discovery for the flora of Vietnam based on the specimens collected in Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province. The present study provided the detailed characteristics of the species including detailed photographs of the morphological characteristics, the cross section of the leaf, inflorescence axis and root. Furthermore, the information about the species, including distribution, habitat, ecology and conservation status were also provided.

Spatial orientation of gynoecium in legumes and beyond: Commentary to the paper of Wang et al. (2021)

The third largest angiosperm family, Leguminosae, exhibits a relatively wide range of variation in morphology of gynoecium. Some of gynoecial patterns found in this taxon are of special interest, as they resemble ones previously described in the earliest angiosperms. The different orientations of carpels in legumes appear easily switchable through changes in flower symmetry and floral meristem sizes. Regardless of orientation of a single carpel with respect to the inflorescence axis, the placenta-bearing suture invariably remains adaxial as related to the floral axis. This conclusion relaxes the existing controversies between the supposed megasporophyll- derived nature of the carpel and observed diversity of placentation in known Mesozoic angiosperms.

Comparative Transcriptome Analysis of a Fan-shaped Inflorescence in Pineapple Using RNA-seq

Background: Pineapple plant usually has a capitulum. However, a fan-shaped inflorescence was evolved in an exceptional material, having multiple crown buds. In order to reveal the molecular mechanisms of the formation of the fan-shaped inflorescence, fruit traits and the transcriptional differences between a fan-shaped inflorescence (FI) and a capitulum inflorescence (CI) pineapples were analyzed in the three tissues, i.e., the flower stem apex (FIs and CIs), the base of the inflorescence (FIb and CIb), and the inflorescence axis (FIa and CIa).Results: Except for a clear differentiation of inflorescence morphology, no significant differences in the structure of inflorescence organs and the main nutritional components (soluble solids, soluble sugar, titratable acid, and VC) in fruits were found between the two pineapples. Between the fan- and capitulum-shaped inflorescences, a total of 5370 differentially expressed genes (DEGs) were identified across the three tissues; and 3142, 2526 and 2255 DEGs were found in the flower stem apex, the base of the inflorescence, and the inflorescence axis, respectively. Of these genes, there were 489 overlapping DEGs in all three tissue comparisons. In addition, 5769 DEGs were identified between different tissues within each pineapple. Functional analysis indicated between the two pineapples that 444 transcription factors (TFs) and 206 inflorescence development related genes (IDGs) were differentially expressed in at least one tissue comparison, while 45 TFs and 21 IDGs were overlapped across the 3 tissues. Among the 489 overlapping DEGs in the 3 tissue comparisons between the two pineapples, excluding the IDGs and TFs, 80 of them revealed a higher percentage of involvement in the biological processes relating to response to auxin, and reproductive processes. RNA-seq value and real-time quantitative PCR analysis exhibited the same gene expression patterns in the three tissues. Conclusions: Our result provided novel cues for understanding the molecular mechanisms of the formation of fan-shaped inflorescence in pineapple, making a valuable resource for the study of plant breeding and the speciation of the pineapples.

Phylogeny and taxonomy of Habenaria leprieurii, H. alpestris and H. sect. Microdactylae (Orchidaceae), with descriptions of two new taxa

Habenaria leprieurii and H. alpestris both have histories of misleading and conflicting taxonomic identifications. We investigated the taxonomy, phylogenetic relationships, and sectional classification of those and related species. Examinations of type specimens and large numbers of additional live and herborized samples revealed that H. schwackei, H. amazonica, and H. platydactyla are conspecific with H. leprieurii and are characterized by having a white corolla and a long pedicel. The species previously treated as H. leprieurii, is H. cruegerii, of which H. culmiformis is a synonym and are characterized by the green flowers, short pedicel and the straight ovary, parallel to the inflorescence axis, curved only in the apex. A species from central-western Brazil, previously treated as H. alpestris, corresponds to a new species, described here as H. omissa, while H. alpestris is conspecific with H. melanopoda. We propose a new circumscription for H. sect. microdactylae, including H. leprieurii, H. heptadactyla, H. cruegerii, and the newly described H. omissa and H. cruegeri var. flaviflora—which now form a morphologically homogeneous section. An identification key, plus descriptions, notes, illustrations, and lists of specimens for each species are presented.

Rubus prissanicus (Rosaceae), a new bramble species from North West Poland

Rubus prissanicus, a new regional apomictic species, is described from north-western Poland. It is similar to R. lindleianus and R. langei, however it differs from the former species by broader leaflets and less numerous prickles on the inflorescence axis, and from the latter by unequally serrate leaflet margin, and from both these species by different types of trichomes on abaxial leaflet surface. Unlike other Polish species of R. ser. Rhamnifolii, in which the indumentum of abaxial leaf surface consists mainly of branched hairs, simple trichomes are the main component of indumentum of R. prissanicus leaves. The new species has been observed mainly on fertile soils, in broadleaf forest habitats, usually in fairly sunny places, along forest margins, by forest roads, in clearings, and in wayside thickets.