Research on Leaf Anatomical Structure of Psammosilene tunicoides Populations under Water-limited Conditions

[Objective] This study aimed to investigate the leaf anatomical structures of P. tunicoides populations under water-limited conditions. [Method] 2-year-old seedlings of herbaceous perennial P. tunicoides that was introduced into the experi- mental field were selected as the research objects. Under the well-watered and wa- ter-limited conditions, we conducted the comparative observation of leaf anatomical structure and stomatal characteristics of two populations by using paraffin slice method and imprinting method. [Result] The result showed that the upper cuticle of P. tunicoides leaves were thickened, the palisade tissue/spongy tissue ratio, vascular bundle diameter and number of xylem vessels in main vein had increased, the stomatal opening became smaller and the stomatal density had increased in winter- spring drought period under water-limited conditions. The plasticity of above traits could be regarded as the important indicators for detecting the responses of P. tunicoides populations to water-limited conditions. Meanwhile, variation amplitudes of these indicators were different among populations. Leaf anatomical structure and stomatal characteristics in Lijiang Axi population under water-limited conditions varied significantly, which might cause the stronger adaptability of this population to drought conditions. [Conclusion] This research provided a reference for the selection of drought-resistant P. tunicoides germplasm and exploration of the adaptive differentia- tion of P. tunicoides populations under natural drought conditions.

Two New Cyclic Peptides from Psammosilene tunicoides

From Psammosilene tunicoides W. C. Wu et C. Y Wu, two cyclic octapeptides (namedpsammosilenins A and B) were isolated. Their structures were determined as cyclo(-Pro1-phe1-Pro2-Phe2-Phe3-Ala-Pro3-Leu-) and cyclo(-Pro1-Gly-Phe1-Val-Pro2-Phe2-Thr-Ile) by spectroscopicmethods.

Root morphology and biomass accumulation in hairy root culture of Psammosilene tunicoides by exogenous auxin treatments

Root morphology,growth rate and biomass accumulation in hairy root culture could be impacted by auxins.In this study,we investigated the responses of the morphology and growth of Psammosilene tunicoides hairy roots to different treatments of auxins at several concentrations in solid or liquid media.Results show that Naphthylacetic acid(NAA)principally accelerates the P.tunicoides primary or lateral hairy root elongation,while indolebutyric acid(IBA)mainly increases lateral hairy root density.The biomass of hairy roots was generally promoted by NAA,IBA or NAA/IBA combination.The optimal concentrations of NAA,IBA and NAA/IBA for root biomass enhancements are 0.5,0.1,0.5/0.2 mg/L for solid media,and 0.1,0.1,0.05/0.2 mg/L for liquid media,respectively.This study positively suggests that the root morphology of P.tunicoides hairy root can be improved by optimizing the ratio of NAA/IBA in the culture media,leading to an improving biomass in hairy root culture.