Comparisons of stomatal parameters between normal and abnormal leaf of Bougainvillea spectabilis Willd

In this study, stomatal density (SD), stomatal index (SI), epidermal cell density (ED), guard cell length (GCL) and guard cell width (GCW) of normal and abnormal leaf of Bougainvillea spectabilis Willd were studied. This can be useful for further research of physical mechanism of abnormal leaf. Epidermal cells were polygonal with straight anticlinal walls in the adaxial epidermis of normal leaf; while in the abaxial epidermis of normal leaf, the epidermal cells were irregular with repand anticlinal walls. The stomata were anomocytic on normal leaf. No stomata were found in the adaxial epidermis of abnormal leaf. In abaxial epidermis of abnormal leaf, the epidermal cells were repand or sinuous. The stomata were anomocytic on abnormal leaf. The guard cells were kidney-shaped on normal and abnormal leaf. SD and SI of normal leaf were significantly higher than that of abnormal leaf. ED and GCL of abnormal leaf were higher than that of normal leaf in relative leaves length 37.5 and 50%. At other four stages, ED and GCL of abnormal leaf were smaller than that of normal leaf. SD, SI and ED had a negative correlation with relative leaf length; a significant positive correlation was observed between GCL and relative leaf length.Key words: Bougainvillea spectabilis Willd, normal leaf, abnormal leaf, stomatal density, epidermal cell density, stomatal index

Lead-induced changes in plant morphology, cell ultrastructure, growth and yields of tomato

A pot experiment in plastic greenhouse was conducted to investigate the effect of Pb toxicity on development and ultrastructure of tomato (Lycopersicon esculentum Mill. cv. ZZ203) by four levels of Pb addition [0, 150, 450, and 900 mg/kg Pb in soil as Pb(NO3)]. The results showed that excess lead resulted in dwarf plants, wilting and misshapened leaves accompanied by less number, less numbers of the calyx, and longer-smaller fruits. At the same time, the condensed cytoplasm accompanied by the department of plasma from cell wall, swollen mitochondrial and chloroplast including thylakoid, fewer cristae in mitochondrial, loosely combined thylakoid to form askew grana, disruption plasma membrane and also followed with dilation organelles were all the typical toxic symptoms of Pb stress. Otherwise, plant biomass and fruit yields decreased as Pb increased: treatment or addition of Pb (150 mg/kg) decreased the aforestated parameters, but these differences did not approach significance at 5% level of probability; however, Pb (450 or 900 mg/kg) treatment, significantly decreased the aforementioned parameters. Excess lead (900 mg/kg) inhibited biomass and fruit yields by 71 and 51% as compared to the zero Pb control treatment respectively. Concentration of Pb in plant tissues decreased in the following order: fruits, leaves, stems and roots.Key words: Lead, tomato, plant morphology, ultrastructure, growth, yield

Stiffness Optimized Multi-Robot Behavior Planning using Reduced Hessian Method

Stiffness is a critical weakness in robot-driven manufacturing. Following the idea of enhancing stiffness by physically coupling multiple robots, the cooperative behavior should be optimized. We present a reduced Hessian method to generate stiffness optimized placement and motion for coupled robots with given manufacturing processes. To improve efficiency the search space dimension of the optimization problem is reduced while the high-dimensional path and coupling constraints are satisfied in each iteration. By integrating a stiffness model in the optimization, cooperative behavior with stiffness enhancement is generated. The results are validated by experiments for both 7-axis and 6-axis robots with physical coupling

Changing characteristics of the water consumption structure in Nanjing city, Southern China

Understanding the changes in water consumption structure in order to take measures for demand control is very important for sustainable water resources management. In this study, using the Southern China area of Nanjing as an example, we employed the information entropy method to analyze the water consumption structure, as well as the grey incidence analysis to analyze synthetic incidence degree of the factors associated with agricultural, industrial, domestic, and ecological water consumption. The results show that the degree of balance among water consumption sectors has increased from 0.755 to 0.825 between 1993 and 2014. Gradual decrease of the relative proportion of a single water user structure in a water consumption system has made the utilization of water resources in Nanjing rational and diversified. The study identifies three stages of transformation of water structure in Nanjing, namely, a growth period from 1993 to 2002, an adjustment period from 2003 to 2010, and another growth period from 2011 to 2014. The synthetic incidence degree analysis indicates that adjustments of the agricultural and industrial water consumption as well as water saving measures are the main factors that affected water consumption structure in Nanjing. It is expected that the results obtained from this study will provide references to optimize the utilization of urban water resources