Palyno-anatomical studies of monocot taxa and its taxonomic implications using light and scanning electron microscopy.

Palyno-anatomical study of monocots taxa using Light and Scanning Electron Microscopy (SEM) was first time conducted with a view to evaluating their taxonomic significance. Studied plants were collected from different eco-climatic zones of Pakistan ranges from tropical, sub-tropical, and moist habitats. The aim of this study is to use palyno-anatomical features for the correct identification, systematic comparison, and investigation to elucidate the taxonomic significance of these features, which are useful to taxonomists for identifying monocot taxa. A signification variation was observed in quantitative and qualitative characters by using the standard protocol of light microscopy (LM) and SEM. Epidermal cell length varied from maximum in Allium griffthianum (480 ± 35.9) µm at the adaxial surface to minimum in Canna indica (33.6 ± 8.53) µm on abaxial surface. Maximum exine thickness was observed in Canna indica (4.46) µm and minimum in Allium grifthianum (0.8) µm. Variation was observed in shape and exine ornamentation of the pollen, shape of the epidermal cell, number, size, and type of stomata, guard cell shape, and anticlinal wall pattern. Based on these palyno-anatomical features a taxonomic key was developed, which help in the discrimination of studied taxa. In conclusion, LM and SEM pollen and epidermal morphology is explanatory, significant, and can be of special interest for the plant taxonomist in the correct identification of monocots taxa.

Optimization of extraction process and antioxidant activity of polysaccharides from leaves of Paris polyphylla.

Based on a single-factor test, a central composite design was used to optimize the extraction conditions of polysaccharides from leaves of Paris polyphylla Smith var. yunnanensis (Franch.) Hand.-Mazz. Three independent variables, including extraction temperature (°C), ratio of water to raw material, and extraction time (h), which significantly affected the yield of polysaccharides, were investigated. The experimental data were fitted to a quadratic polynomial equation using multiple regression analysis and also examined using appropriate statistical methods. The optimum conditions were as follows: extraction temperature, 90.8°C; ratio of water to raw material, 21.3:1; and extraction time 4.8h. Under these conditions, the experimental yield was 54.18%, which matched the predicted value well. Furthermore, the purified polysaccharide exerted strong antioxidant effects on DPPH, hydroxyl, and superoxide radicals in vitro.

Acetylcholinesterase-inhibiting alkaloids from Zephyranthes concolor.

The bulbs and aerial parts of Zephyranthes concolor (Lindl.) Benth. & Hook. f. (Amaryllidaceae), an endemic species to Mexico, were found to contain the alkaloids chlidanthine, galanthamine, galanthamine N-oxide, lycorine, galwesine, and epinorgalanthamine. Since currently only partial and low resolution (1)H-NMR data for chlidanthine acetate are available, and none for chlidanthine, its 1D and 2D high resolution (1)H- and (13)C-NMR spectra were recorded. Unambiguous assignations were achieved with HMBC, and HSQC experiments, and its structure was corroborated by X-ray diffraction. Minimum energy conformation for structures of chlidanthine, and its positional isomer galanthamine, were calculated by molecular modelling. Galanthamine is a well known acetylcholinesterase inhibitor; therefore, the isolated alkaloids were tested for this activity. Chlidanthine and galanthamine N-oxide inhibited electric eel acetylcholinesterase (2.4 and 2.6 × 10(-5) M, respectively), indicating they are about five times less potent than galanthamine, while galwesine was inactive at 10(-3) M. Inhibitory activity of HIV-1 replication, and cytotoxicity of the isolated alkaloids were evaluated in human MT-4 cells; however, the alkaloids showed poor activity as compared with standard anti-HIV drugs, but most of them were not cytotoxic.

Cadmium induces hypodermal periderm formation in the roots of the monocotyledonous medicinal plant Merwilla plumbea.

BACKGROUND AND AIMS: Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminated with metals from mining activities, the danger of human intoxication exists. An experiment with plants exposed to cadmium (Cd) was performed to investigate the response of M. plumbea to this heavy metal, its uptake and translocation to plant organs and reaction of root tissues. METHODS: Plants grown from seeds were cultivated in controlled conditions. Hydroponic cultivation is not suitable for this species as roots do not tolerate aquatic conditions, and additional stress by Cd treatment results in total root growth inhibition and death. After cultivation in perlite the plants exposed to 1 and 5 mg Cd L(-1) in half-strength Hoagland's solution were compared with control plants. Growth parameters were evaluated, Cd content was determined by inductively coupled plasma mass spectroscopy (ICP-MS) and root structure was investigated using various staining procedures, including the fluorescent stain Fluorol yellow 088 to detect suberin deposition in cell walls. KEY RESULTS: The plants exposed to Cd were significantly reduced in growth. Most of the Cd taken up by plants after 4 weeks cultivation was retained in roots, and only a small amount was translocated to bulbs and leaves. In reaction to higher Cd concentrations, roots developed a hypodermal periderm close to the root tip. Cells produced by cork cambium impregnate their cell walls by suberin. CONCLUSIONS: It is suggested that the hypodermal periderm is developed in young root parts in reaction to Cd toxicity to protect the root from radial uptake of Cd ions. Secondary meristems are usually not present in monocotyledonous species. Another interpretation explaining formation of protective suberized layers as a result of periclinal divisions of the hypodermis is discussed. This process may represent an as yet unknown defence reaction of roots when exposed to elemental stress.

Pectin dynamic and distribution of exchangeable Ca2+ in Haemanthus albiflos hollow style during pollen-pistil interactions.

In this report, the localization and spatial distribution of two categories of pectin, high and low methylesterified, on the background of dynamic in loosely bound calcium (Ca(2+)) in Haemanthus hollow style were studied before and after pollination. In the style transmitting tract of unpollinated pistil, mainly high-methylesterified pectins were present, both in the transmitting tract epidermis and in the style canal. After pollination, an increase in the level of two investigated categories of pectin was observed, but the amount of high-methylesterified one in each period of time analyzed was permanently higher. Locally, in the regions of the style canal penetrated by pollen tubes, process of pectin de-esterification was initiated. However, pollination caused an increase of loosely bound Ca(2+) level in the style transmitting tract, this process appears to be not linked with pectin de-esterification and possible Ca(2+) release after the lysis of Ca(2+) cross-linked de-esterified pectin. Instead, it seems to be based on Ca(2+) exocytosis from the transmitting tract epidermis cells providing a source of Ca(2+) for pollen tubes growing in Haemanthus hollow style.

[Morphological variations of Paris polyphylla var. yunnansensis in different population].

OBJECTIVE: To study the morphological variations of Paris polyphylla var. yunnansensis in different population for genetic diversity and breeding. METHOD: The characters of roots, stalks, leave and flowers were observed. The results were analyzed by DPS software. RESULT AND CONCLUSION: P. polyphylla var. yunnansensis showed plenty genetic diversity, there existed obvious differences in morphological characters of different population. Principal components analysis showed that the number of calyces, petal, carpels, stamens is main factor,which causes the morphological variations in different population. Cluster analysis shows that 26 populations are incorporates in two types as 45.08 Euclidean distance. Leaf area index is distinct different in this two types.

[A model atlas of the crude drug Radix Ophiopogonis in tri-dimensional computer reconstraction from their serial transections].

In this paper, the tri-dimensional computer reconstruction and animated display from the serial transections of the crude drugs Radix Ophiopogonis and Radix Liriopes have been achieved. Accordingly, some tri-dimensional image techniques and information for the computer aided teaching and identification of pharmacognosy have been offered.

[Microscopic identification of beimu grown in Yunnan province].

This paper deals with the microscopic identification of the bulbs of 5 Fritillaria species from Yunnan Province, namely: F. cirrhosa, F. cirrhosa var. purpurea, F. cirrhosa var. viridiflava, F. delavayi and F. crassicaulis. Based on the shape, size, hilum and striation of the starch grain and the cuticular veins of the upper epidermis cell of the scales, these species could be distinguished obviously.