Interplant communication: airborne methyl jasmonate is essentially converted into JA and JA-Ile activating jasmonate signaling pathway and VOCs emission.

Methyl jasmonate (MeJA) was identified as an airborne signal involved in mediating interplant defense response communications over a decade ago. However, how MeJA activates plant defense systems and what becomes of the compound after it has done so has, thus far, remained unknown. To investigate this, Achyranthes bidentata plants were exposed to deuterated methyl jasmonate (d(2)MeJA) followed by absolute quantification of metabolic products of d(2)MeJA, and emissions of volatile organic compound (VOC) as defensive markers. We found that d(2)MeJA was metabolized mainly into deuterated jasmonic acid (d(2)JA) and jasmonoyl isoleucine (d(2)JA-Ile), and to a much lesser extent, deuterated jasmonoyl leucine (d(2)JA-Leu). Increases in d(2)JA-Ile/Leu and also endogenous JA-Ile/Leu were tightly co-related with, and significantly influenced the pattern and amount of, VOC emissions. The amount of accumulated d(2)JA-IIe was 13.1-fold higher than d(2)JA-Leu, whereas the amounts of JA-IIe and JA-Leu accumulated were almost identical. This study demonstrates that exogenous MeJA activates defensive systems (such as VOC emissions) in receiver plants by essentially converting itself into JA and JA-IIe and initiating a signal transduction leading to VOC emissions and induction of endogenous JA-IIe and JA-Leu, which in turn cause further amplification of VOC emissions.

[Comparative research on vitality and characteristics of seeds of Achyranthes bidentata in different producing area].

OBJECTIVE: To study the germination property of the seeds of Achyranthes bidentata from different producing area, providing foundation for choosing the better seed resources. METHOD: The germination rate, germination energy, germination index, vigor and the characteristics of the seeds of A. bidentata from different producing area were compared, and the relative electric conductivity was measured. The characteristics of the seed were recorded through the Anymicro DSS YT-5M microscope digital camera, and the differences were analyzed. RESULT: Seed from Henan Boai and Hebei Anguo showed the better germination rate, germination energy, germination index and vigor. CONCLUSION: The seeds from both Henan Boai and Hebei Anguo showed the better quality.

In vitro callus induction and plantlet regeneration of Achyranthes aspera L., a high value medicinal plant.

OBJECTIVE: To study callus induction from different explants (internode, leaf, root) and in vitro plantlets propagation from medicinally important plant Achyranthes aspera L. METHODS: Sterilized explants were prepared by using 0.1% HgCl2 and 0.5% Bavistin and callus was obtained when cultured onto Murashige Skoog's (MS) medium by using different concentrations and combination of 2,4-D, NAA, BAP, IAA, IBA with 3% sucrose and 0.8% agar. Induced callus was immediately transferred to MS medium containing at different concentrations of phytohormones for shootlets and rootlets induction respectively. RESULTS: Sterilization treatment of 0.1% HgCl2 for 2-3 min and Bavistin 0.5% for 10-12 min showed the highest percentage of asepsis and survival rate. Maximum induction of callus was obtained from a combination of 2.0 mg/L 2,4-D and 0.5 mg/L NAA from leaf. Highest shootlets number (4.83±0.17) and length (3.8±0.16) cm were observed on full strength MS medium when fortified with BAP 4.0 mg/L and KIN 0.5 mg/L. Concerted efforts of BAP 2.0 mg/L and NAA 0.5 mg/L on full strength MS medium showed highest leaf number (6.77±0.94). In vitro raised shoots were allowed to root on different strengths of MS medium fortified with IAA and IBA at different concentrations. Experimentally, 3.0 mg/L IBA was enabled to induce maximum rootlets number (10.0±9.82) on full strength MS medium. Afterwards, regenerated shoots with well developed roots were successfully subjected to hardening process and were acclimatized. The survived plantlets showed 66.67% survival frequency without any morphological abnormality. CONCLUSIONS: The results demonstrated that different explants were good source of callus induction, morphology analysis as well as indirect plantlets regeneration.

[Structural development of root and their relationship to accumulation of triterpenoid saponins in Achyranthes bidentata Bl].

A study concerning the relationship of dynamic accumulation of triterpenoid saponins and anatomical characteristics of Achyranthes bidentata Bl roots was undertaken by anatomical, histochemical and phytochemical method respectively. Results revealed that the primary and secondary structures of the root resembled those of usual dicots. The continual thickening growth of root principally resulted from the differentiation and development of the tertiary structure. The first ring of supernumerary cambium originated from the parenchyma and vascular ray cells of secondary phloem and each of the followed rings initiated in the outmost foundamental parenchyma cells which were derived from the immediate preceding ring. In the supernumerary cambiums, there had not distinction between the fusiform initial and the ray initial. Its cells present stratifide arranged from a longitudinal section through root. Regular and concentric rings of tertiary vascular bundles who differentiate centrifugally were enclosed by the connective parenchyma. The number of the rings continually increase with the development of the root itself. Triterpenoid saponins accumulated mainly in pericycle, primary phloem and parenchyma between primary phloem and xylem in the primary structure of root but came into existence in cells of secondary phloem and phelloderm with secondary structure development of root, and as well as in supernumerary cambium and phloem of tertiary vascular bundle after the tertiary structure maturated gradually in the roots. The investigation provides indications that the tertiary structure were not only main parts in the roots of Achyranthes bidentata Bl, but also important storage region of triterpenoid saponins in its growth and development. In addition, the analysis of using the HPLC showed that dynamic increasing trend oleanolic acid was as "S" curve during the roots growth and development and up to the highest content of triterpenoid saponins after plants grew 120 days. Meanwhile, the number of the rings of tertiary vascular bundles, length and diameter of the roots were the same as the triterpenoid saponins increasing trend. It should be optimal season for harvest.