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Running bamboos are a group of clonal plants exhibiting rapid and widespread expansion. They possess two root subsystems, arising from different shoot parts, culm roots and rhizome roots. To date, it remains unclear what the functional differences are between the two root subsystems and what their relation is to the remarkably competitive ability of running bamboos.A typical running bamboo, Phyllostachys glauca, which dominates in a highly heterogeneous habitat of limestone hills, was sampled to compare the morphology, architecture, anatomy, chemical composition, mechanics and nutrient acquisition of the two root subsystems to explore their differences in functional traits.Compared with rhizome roots, culm roots possessed greater tensile strength, modulus of elasticity, stele diameter to root diameter ratio, root tissue density, root length density, rooting depth, basal diameter of shoot‐borne roots and more lignified cells. Culm roots also had a higher phosphorus (P) concentration (>0.4 mg g−1), which was nearly twice that of rhizome roots. By contrast, rhizome roots exhibited a greater specific root area, specific root length, cortex thickness to root radius ratio, total branch order and greater P‐uptake capacity than culm roots.Our findings revealed distinct differences in functional traits between culm roots and rhizome roots in P. glauca. Culm roots are considered to primarily provide anchorage, but also function in resource acquisition and nutrient storage, while rhizome roots mainly play a role in resource acquisition. Except for the anchorage and resource acquisition of culm roots, the extra resource acquisition by rhizome roots and the high concentration of a limiting nutrient (P) in culm roots enhance the performance in a highly heterogeneous habitat which offers a physiological explanation for P. glauca dominating on limestone hills.The functional differentiation between culm roots and rhizome roots provides insight into the mechanism underpinning the remarkable expansion of running bamboos and offers a new perspective to explain the strong competitive ability of clonal plants with dimorphic roots. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Our and other studies have reported that homocysteine thiolactone ( HTL) could induce endothelial dysfunction. However, the precise mechanism was largely unknown. In this study, we tested the most possible factor-endoplasmic reticulum ( ER) stress, which was demonstrated to be involved in endothelial dysfunction in cardiovascular disease. Acetylcholine (Ach)-induced endothelium-dependent relaxation ( EDR) and biochemical parameters were measured in rat isolated aorta. The level of reactive oxygen species ( ROS) and NO was designed by specific fluorescent probe DCFH- DA and DAF- FM DA separately. The nuclear translocation of the NF-κB was studied by immune-fluorescence. The mRNA expression and protein expression of GRP78-a key indicator for the induction of ER stress-were assessed by real-time PCR and Western blot. Two ER stress inhibitors-4- PBA (5 m m) and Tudca (500 μg/mL)-significantly prevented HTL-impaired EDR and increased NO release, endothelial nitric oxide synthase ( eNOS) and SOD activity, decreased ROS production, NADPH activity, NOX-4 mRNA and MDA level. We also found that 4- PBA and Tudca blocked HTL-induced NF-κB activation thus inhibiting the downstream target gene production including TNF-α and ICAM-1. Simultaneously, HTL increased the mRNA and protein level of GRP78. HTL could induce ER stress leading to a downstream enhancement of oxidative stress and inflammation, which finally caused vascular endothelial dysfunction. [ABSTRACT FROM AUTHOR]

Through the use of the so-called variational Lyapunov method, which is developed by combining the method of variation of parameters and the Lyapunov second method, stability and instability properties in terms of two measures for impulsive differential equations with variable moments of impulsive effects are discussed. Some stability and instability criteria are established. These theorems, together with an example, show that perturbation and impulsive effects may make a stable system uniformly asymptotically stable or unstable. These results significantly generalize the known ones. [ABSTRACT FROM PUBLISHER]