The designed lens central thickness measuring optical system is a kind of new system based on chromatic confocal principle, which can fast and automatically measure center thickness of lens without contact of lens surfaces. In order to expand measuring range of device, multiple configuration modes are established to eliminate monochromatic aberrations within each configuration, and enlarge the D-value of image distance to increase the longitudinal chromatic aberration. In this way, the longitudinal chromatic aberration of the system can reach about 30 mm in the wavelength range from 400 nm to 1000 nm. The maximum measurable lens thickness can be more than 30 mm by using this optical system. Measurement of three different lenses whose central thicknesses are 6, 15 and 30 mm is done. The results show that the measuring accuracies for the three lenses are ±2.5, ±3.5 and ±5.0 μm.

Endophytes are commonly defined as fungi that live asymptomatically within healthy plant tissue, such as leaves, stems or roots, for a part or all of their life cycle. The largest plant family hosting these endophytes is Poaceae. Studies on the grass鄄endophyte symbiosis indicate that endophytes can not only protect the host grass from abiotic stresses but also enhance its resistance to biotic disturbance, including herbivores, nematodes, bacteria and pathogens. However, the response of grass鄄endophyte symbiosis to fungal pathogens is less studied. Most previous reports on resistance of endophytes to pathogens have focused on inhibition of fungal pathogens by endophytes in vitro or by inoculation of fungal pathogens on detached leaves of the symbiont, and these studies have demonstrated that endophytes can inhibit growth of certain species of fungal pathogens to some degree. Up to now, only a few studies have centered on influence of endophyte infection on disease resistance of live plants. In this paper we used the endophyte Epichlo觕 bromicola, which was isolated from Leymus chinensis. L. chinensis is a natural grass, widely distributed in the Inner Mongolian steppe. Three species of fungal pathogens were chosen, i.e. Curvularia lunata, Bipolaris sorokiniana and Cladosporium sp.. The experiment comprised three parts, i. e. fungal pathogens inhibition experiment by endophyte, infected detached leaves and infected intact plants experiments. The questions were: (1) whether E. bromicola could inhibit the growth of the three fungal pathogens in vitro, and (2) whether endophyte鄄infected (E+) and endophyte鄄free (E-) plants differed in resistance to the pathogenic fungi in detached leaves and live plants of L. chinensis. The results suggested that E. bromicola significantly inhibited the growth of C. lunata, B. sorokiniana and C. sp. in vitro, but anti鄄fungal activities of the endophyte to different pathogenic fungi were different.

No abstract

No abstract

No abstract