Ultrastructure and energy dispersive spectroscopy-based elemental analysis of the fruit exocarps of Musa sinensis L. (Banana) and Musa paradisiaca L. (Plantain) (Musaceae)

Ultrastructural investigation and analysis of the elemental spectra composition of Musa sinensis L. and Musa paradisiaca L. exocarp (peels) was carried out using the Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) respectively. Microstructures such as interlocked, polyhedral epidermal cells, ellipsoid-shaped stomata, guard cells, intercellular space, anticlinal-patterned walls and subsidiary cells were observed, with direct and indirect implications in the deposition of important primary and secondary metabolites, thus connoting some medicinal significance. Furthermore, the energy dispersive x-ray spectra revealed the presence of some important elements such as potassium (K), iron (Fe), carbon (C), oxygen (O), silicon (Si) and gold (Au), with high to relatively high carbon and oxygen peaks consistently observed in Musa sinensis and Musa paradisiaca. In the same vein, the relative similarity observed in the constituents of quite a number of the elemental spectra (carbon, oxygen, silicon, gold) in M. sinensis and M. paradisiaca peels, also reflects species relatedness between M. sinensis and M. paradisiaca.

Haploid induction in tropical supersweet corn and ploidy determination at the seedling stage

The objective of this work was to determine the possibility of haploid induction in tropical supersweet corn (Zea mays L. var. saccharata) using a maternal inducer, as well as to identify alternative methods for haploid selection. A single-cross hybrid of field corn and 11 tropical supersweet corn populations were crossed with the haploid inducer. The haploids were pre-selected using the R1-navajo marker and were differentiated into haploids or false positives at the V2-V3 stage, based on the color of the first leaf sheath and on the length of stomata guard cells. The obtained results are indicative of the possibility of inducing maternal haploids in populations of tropical supersweet corn. However, a large number of false-positive haploids were incorrectly selected by the R1-navajo marker. The color of the first leaf sheath was efficient for haploid identification in supersweet corn populations, and the method based on stomata morphometry can be used when there is no color distinction on the first leaf sheath.

Leaf fossils of Proteaceae tribe Persoonieae from the Late Oligocene - Early Miocene of New Zealand

Fossils from the Newvale lignite mine, Southland, are the first substantiated foliar records of Proteaceae subfamily Persoonioideae. The fossils possess very large stomata, a probable synapomorphy for Persoonioideae, and within Proteaceae the combination of this feature and more or less parallel-aligned, brachyparacytic stomatal complexes and undulate anticlinal epidermal cell walls is uniquely found in this subfamily. The new genus Persoonieaephyllum is described to recognise affinity of the fossil leaves and cuticles with tribe Persoonieae of Persoonioideae and their distinction from its only other extant representative, Placospermum. Two new species are described. P. ornatum is represented by linear leaves less than 20 mm wide and possessing more or less parallel-aligned major veins. These leaves closely match those of extant hypostomatic, broad-leaved species of tribe Persoonieae and are distinct from Placospermum in venation and several cuticular details. P. villosum has so far been recovered only as cuticular material in disaggregated lignite. It is distinct from P. ornatum in having abundant trichome bases, an absence of surface tubercules, and even larger stomata (guard cells often >70 μm long). The fossils extend the known record of Persoonioideae in the New Zealand–New Caledonia region by ~20 million years.