Iron Supplement-Enhanced Growth and Development of Hydrangea macrophylla In Vitro under Normal and High pH.

Hydrangea macrophylla is a popular perennial ornamental shrub commercially grown as potted plants, landscape plants, and cut flowers. In the process of reproduction and production of ornamental plants, the absorption of nutrients directly determines the value of the ornamental plants. Hydrangea macrophylla is very sensitive to the content and absorption of the micronutrient iron (Fe) that affects growth of its shoots. However, the physiological activity of Fe as affected by deficiency or supplementation is unknown. This work aimed at preliminary exploring the relationship between Fe and photosynthesis, and also to find the most favorable iron source and level of pH for the growth of H. macrophylla. Two Fe sources, non-chelated iron sulfate (FeSO4) and iron ethylenediaminetetraacetic acid (Fe-EDTA), were supplemented to the multipurpose medium with a final Fe concentration of 2.78 mg·L-1. The medium without any Fe supplementation was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70, before autoclaving. The experiment was conducted in a culture room for 60 days with 25/18 °C day and night temperatures, and a 16-hour photoperiod provided at a light intensity of 50 mmol·m-2·s-1 photosynthetic photon flux density (PPFD) from white light-emitting diodes. Supplementary Fe increased the tissue Fe content, and leaves were greener with the medium pH of 4.70, regardless of the Fe source. Compared to the control, the number of leaves for plantlets treated with FeSO4 and Fe-EDTA were 2.0 and 1.5 times greater, respectively. The chlorophyll, macronutrient, and micronutrient contents were the greatest with Fe-EDTA at pH 4.70. Furthermore, the Fe in the leaf affected the photosynthesis by regulating stomata development, pigment content, and antioxidant system, and also by adjusting the expression of genes related to Fe absorption, transport, and redistribution. Supplementation of Fe in a form chelated with EDTA along with a medium pH of 4.70 was found to be the best for the growth and development of H. macrophylla plantlets cultured in vitro.

Towards Low-Cost Hyperspectral Single-Pixel Imaging for Plant Phenotyping.

Hyperspectral imaging techniques have been expanding considerably in recent years. The cost of current solutions is decreasing, but these high-end technologies are not yet available for moderate to low-cost outdoor and indoor applications. We have used some of the latest compressive sensing methods with a single-pixel imaging setup. Projected patterns were generated on Fourier basis, which is well-known for its properties and reduction of acquisition and calculation times. A low-cost, moderate-flow prototype was developed and studied in the laboratory, which has made it possible to obtain metrologically validated reflectance measurements using a minimal computational workload. From these measurements, it was possible to discriminate plant species from the rest of a scene and to identify biologically contrasted areas within a leaf. This prototype gives access to easy-to-use phenotyping and teaching tools at very low-cost.

Multilocus coalescent species delimitation to evaluate traditionally defined morphotypes in Hydrangea sect. Asperae (Hydrangeaceae).

The number of species recognized in section Asperae of the flowering plant genus Hydrangea differs widely between subsequent revisions. This variation is largely centered around the H. aspera species complex, with numbers of recognized species varying from one to nearly a dozen. Despite indications of molecular variation in this complex, no sequence-based species delimitation methods have been employed to evaluate the primarily morphology-based species boundaries. In the present study, a multi-locus coalescent-based approach to species delimitation is employed in order to identify separate evolutionary lines within H. sect. Asperae, using four chloroplast and four nuclear molecular markers. Eight lineages were recovered within the focal group, of which five correspond with named morphotypes. The other three lineages illustrate types of conflict between molecular species delimitation and traditional morphology-based taxonomy. One molecular lineage comprises two named morphotypes, which possibly diverged recently enough to not have developed sufficient molecular divergence. A second conflict is found in H. strigosa. This morphotype is recovered as a separate lineage when occurring in geographic isolation, but when occurring in sympatry with two other morphotypes (H. aspera and H. robusta), the coalescent species delimitation lumps these taxa into a single putative species.

Detection of Nicotiana tabacum Leaf Contamination in Pharmaceutical Products.

Nicotiana tabacum (Solanaceae) is the only species whose leaves can be legally marketed as tobacco according to the Japanese Tobacco Business Act. Nicotine, a major alkaloid produced by N. tabacum leaves, is regulated in pharmaceuticals by the Japanese Pharmaceutical Affairs Law. However, the use of N. tabacum stems as an excipient in pharmaceuticals is permitted, because these contained only a small amount of nicotine. Recently, several reports showed that a substantial amount of nicotine was detected in an OTC pharmaceutical product, in which N. tabacum stems were used as an excipient. Therefore, products containing N. tabacum stems could be contaminated with the leaf material. In the present study, we established a method to detect contamination of N. tabacum stem materials with its leaves, using microscopy to obtain standard reference microphotographs for identification. Cultivated N. tabacum stems and leaves, commercial cigarette leaves, and N. tabacum tissue imported as excipient material were used for preparing the microphotographs. The characteristic N. tabacum leaf structures found in the powdered fragments included: epidermal cells with sinuous anticlinal cell walls, hairs, mesophyll parenchyma with crystalized calcium oxalate (calciphytoliths), and branching vascular bundles derived from reticulate net-veins. A comparison of the microscopic characteristics of an OTC powder with those from the standard reference microphotographs was an effective method for N. tabacum stem and leaf identification. Thus, we evaluated the powdered pharmaceutical product containing N. tabacum stem tissue and Hydrangea serrata (Hydrangeaceae) leaf tissue as excipients, and confirmed the presence of N. tabacum leaf material.

Bouldering: an alternative strategy to long-vertical climbing in root-climbing hortensias.

In the Neotropics, the genus Hydrangea of the popular ornamental hortensia family is represented by climbing species that strongly cling to their support surface by means of adhesive roots closely positioned along specialized anchoring stems. These root-climbing hortensia species belong to the nearly exclusive American Hydrangea section Cornidia and generally are long lianescent climbers that mostly flower and fructify high in the host tree canopy. The Mexican species Hydrangea seemannii, however, encompasses not only long lianescent climbers of large vertical rock walls and coniferous trees, but also short 'shrub-like' climbers on small rounded boulders. To investigate growth form plasticity in root-climbing hortensia species, we tested the hypothesis that support variability (e.g. differences in size and shape) promotes plastic responses observable at the mechanical, structural and anatomical level. Stem bending properties, architectural axis categorization, tissue organization and wood density were compared between boulder and long-vertical tree-climbers of H. seemannii. For comparison, the mechanical patterns of a closely related, strictly long-vertical tree-climbing species were investigated. Hydrangea seemannii has fine-tuned morphological, mechanical and anatomical responses to support variability suggesting the presence of two alternative root-climbing strategies that are optimized for their particular environmental conditions. Our results suggest that variation of some stem anatomical traits provides a buffering effect that regulates the mechanical and hydraulic demands of two distinct plant architectures. The adaptive value of observed plastic responses and the importance of considering growth form plasticity in evolutionary and conservation studies are discussed.

Role of aluminum in red-to-blue color changes in Hydrangea macrophylla sepals.

Red, purple, and blue sepals on selected cultivars of Hydrangea macrophylla were analyzed for their aluminum content. This content was determined to be a function of the sepal color with red sepals possessing 0-10 µg Al/g fresh sepal, purple sepals having 10-40 µg Al/g fresh sepal, and blue sepals containing greater than 40 µg Al/g fresh sepal. Accordingly, the threshold aluminum content needed to change H. macrophylla sepals from red to blue was about 40 µg Al/g fresh sepal. Higher aluminum concentrations were incorporated into the sepals, but this additional aluminum did not affect the intensity or hue of the blue color. These observations agreed with a chemical model proposing that the concentration of the blue Al(3+)-anthocyanin complex reached a maximum when a sufficient excess of aluminum was present. In addition, the visible absorbance spectra of harvested red, purple, and blue sepals were duplicated by Al(3+) and anthocyanin (delphinidin-3-glucoside) mixtures in this model chemical system.

Chemical studies on different color development in blue- and red-colored sepal cells of Hydrangea macrophylla.

To clarify the cause of the difference in blue and red color development of hydrangea sepals, Hydrangea macrophylla, we analyzed the organic and inorganic components in the colored cells. To obtain colored protoplasts, each blue and red sepal tissue was treated with a combination of cellulase and pectinase, and then from the suspension of the olored and colorless protoplast mixture colored cells of the same hue were collected with a micro-pipette. The content of organic components (delphinidin 3-glucoside, chlorogenic acid, neochlorogenic acid and 5-O-p-coumaroylquinic acid) and Al(3+) in each colored cell was quantified respectively by semimicro-HPLC and graphite furnace atomic absorption spectroscopy (GFAAS). In the blue cells 13 eq. of 5-O-acylquinic acids and 1.2 eq. of Al(3+) to anthocyanin were contained. Contrary to this result, in the red cells, only 3.6 eq. of 5-O-acylquinic acids and 0.03 eq. of Al(3+) were detected. A reproduction experiment of each blue and red sepal color by mixing those components concluded that, for blue coloration, both 5-O-acylquinic acids and Al(3+) were essential.