Darkfield and Fluorescence Macrovision of a Series of Large Images to Assess Anatomical and Chemical Tissue Variability in Whole Cross-Sections of Maize Stems

The proportion and composition of plant tissues in maize stems vary with genotype and agroclimatic factors and may impact the final biomass use. In this manuscript, we propose a quantitative histology approach without any section labelling to estimate the proportion of different tissues in maize stem sections as well as their chemical characteristics. Macroscopic imaging was chosen to observe the entire section of a stem. Darkfield illumination was retained to visualise the whole stem cellular structure. Multispectral autofluorescence images were acquired to detect cell wall phenolic compounds after UV and visible excitations. Image analysis was implemented to extract morphological features and autofluorescence pseudospectra. By assimilating the internode to a cylinder, the relative proportions of tissues in the internode were estimated from their relative areas in the sections. The approach was applied to study a series of 14 maize inbred lines. Considerable variability was revealed among the 14 inbred lines for both anatomical and chemical traits. The most discriminant morphological descriptors were the relative amount of rind and parenchyma tissues together with the density and size of the individual bundles, the area of stem and the parenchyma cell diameter. The rind, as the most lignified tissue, showed strong visible-induced fluorescence which was line-dependant. The relative amount of para-coumaric acid was associated with the UV-induced fluorescence intensity in the rind and in the parenchyma near the rind, while ferulic acid amount was significantly correlated mainly with the parenchyma near the rind. The correlation between lignin and the tissue pseudospectra showed that a global higher amount of lignin resulted in a higher level of lignin fluorescence whatever the tissues. We demonstrated here the potential of darkfield and autofluorescence imaging coupled with image analysis to quantify histology of maize stem and highlight variability between different lines.

Cut foliage: potentiality of native Argentine ferns as new ornamental crops

The cut foliage constitutes an important part of the floricultural production since it represents a fundamental element in flower arrangements, and ferns are the complementary elements most used by florists. In Argentina, there is native material that has not been yet domesticated and could have suitable characteristics for foliage use. The objective of the work was to determine the potential use of 15 native ferns as cut foliage through quality parameters and vase life, generating a scoring system that allows a classification list. Morphological descriptors such as petiole length, length and width of the blade, planes in which the fronds are arranged, brightness, consistency, abundance of spores and presence of pests were taken into account. Also, the production of fronds of six selected species with good scores was recorded. The results showed that it is feasible to consider the commercial production of Pityrogramma calomelanos, Niphidium crassifolium, Campyloneurum nitidum, Blechnum austrobrasilianum and Pteris denticulata by the quantity of fronds obtained and their quality, represented by their size. Campyloneurum nitidum excelled for its vase life of more than 26 days and frond production of 273.61 fronds m-2 at second year cultivation. Pteris denticulata produces 179.44 fronds m-2 but vase life was only 7 days.

Analysis of leaf phenotypic diversity of some Hevea Accessions/clones conserved at the Institute of Agricultural Research for Development (IRAD) Ekona, Cameroon

This study was carried out to estimate leaf morphological diversity of some accessions/clones from IRRDB 1981 Hevea germplasm collection conserved at IRAD Ekona, to determine the importance of leaf morphological descriptors in differentiating accessions/clones. A total of 36 clones/ accessions were characterized using 6 leaf morphological descriptors. Analysis of variance showed that there were significant differences in the leaf morphological parameters for the studied clones. The Principal Component Analysis (PCA) showed that all leaf descriptors were informative and contributed significantly to the variation. The first 2 Principal Component scores (PCs) accounted for 88% of the total variation. The cluster analysis based on significant PCs grouped all accessions and clones in to 6 main clusters at the distance of 1.5. This study permits the characterization of Hevea accessions and clones in to diverse groups using leaf morphological descriptors; hence this will be advantageous for production of diverse genotypes during breeding programs to broaden the Hevea gene pool.

Morphological characterization of Moringa oleifera seeds from different crops of Mexico

Objective: to characterize the seeds of Moringa oleifera present in various crops in Mexico morphologically. Design / Methodology / Approach: An analysis of variance, principal components, and conglomerates of qualitative morphological descriptors (shape, color, presence of wings and wing color) and quantitative (length, width, and weight) were carried out. Results: Significant statistical differences (P˂0.05) were found in the seeds' length, width, weight, and almonds. The principal component analysis indicated that components 1 (70.58%) and 2 (25.59%) contributed 96.17% of the variation, and the cluster analysis identified four groups. The evaluated populations showed qualitative variation (shape, color, presence of wings, and color of wings) and quantitative (length, width, and weight). Study limitations/implications: the germination percentage could not be evaluated because no information was obtained on the age of the seed and the storage conditions. Result/Finding:Conclusion: This information enriches the knowledge of Moringa oleifera in Mexico and serves as a basis for selecting materials of most significant interest.

Development of Morphological Descriptors For Characterization of Teak (Tectona Grandis L. f.) Seed Sources In India

Teak (Tectona grandis L.f.) plantations in India has been intensified in the recent past yet, morphological descriptors for teak is still lacking. Hence, this study aimed to develop descriptors using morphological traits. Among 30 seed sources collected from different states of India, 24 morphological descriptors viz., leaf length, leaf width, presence of petiole, petiole length, leaf shape, shape of leaf apex, shape of leaf base, leaf texture, phyllotaxy, leaf attitude, leaf margin, leaf margin undulation, leaf brightness, leaf venation, leaf main vein, leaf veins, leaf vein colour, leaf colour, leaf pubescence, young leaf colour, number of internodes, internodal length, trunk spots and trunk colour were developed based on leaf and stem characteristics. Subsequently, genetic similarity among the sources were estimated by Jaccard similarity index and cluster analysis was performed by Unweighted Pair Group Method with Arithmetic mean (UPGMA) method.

Morphological and Ecogeographic Study of the Diversity of Cassava (Manihot esculenta Crantz) in Ecuador

Cassava (Manihot esculenta Crantz) is a crop of nutritional and economic importance worldwide, cultivated in more than 100 tropical and subtropical countries including Ecuador, where it is traditionally cultivated in the three continental regions: Amazonia, the Coast and in the valleys of the Sierra. The purpose of this study is to characterize 195 accessions from INIAP’s Ecuadorian cassava collection through (1) morphological characterization with qualitative and quantitative descriptors; and (2) ecogeographic characterization to know the climatic, geophysical, and edaphic conditions in which cassava grows and which environments are frequent or marginal for its cultivation. For the morphological characterization, 27 morphological descriptors were used (18 qualitative and nine quantitative), and for the ecogeographic characterization, 55 variables (41 climatic, two geophysical and 12 edaphic). Four morphological groups and three ecogeographic groups were identified. Morphological variability was evidenced mainly in descriptors related to the leaves, stems, and inflorescences. In addition, it was possible to identify accessions that appear capable of growing under extreme conditions of drought and poor soils. These accessions could be used for improvement.