Regeneration of horseradish hairy roots incited by Agrobacterium rhizogenes infection

Surface-sterilized leaf disks of horse-radish (Armoracia lapathifolia) were immersed in a suspension of Agrobacterium rhizogenes harboring the root-inducing plasmid (pRi) and cultured on a solid medium. Within about 10 days after inoculation, adventitious roots (hairy roots) emerged from the leaf disks. No roots emerged from the uninoculated leaf disks. The excised hairy roots grew vigorously in the dark and exhibited extensive lateral branches in the absence of phytohormones. When the hairy roots were moved into the light, numerous adventitious buds thrust out of the roots within about 10 days, and they developed into complete plants (R0 generation). R0 plants revealed leaf wrinkle. Root masses of cultured R0 plants were of two types. One had fibrous roots only and the other had both fibrous and tuberous roots Leaf disks of the R0 plants proliferated adventitious roots (R1 generation) on a solid medium after 1–2 weeks of culture. Phenotypical characters of the R1 roots were the same as those observed with the initial hairy roots. The T-DNA sequences of pRi were detected within DNA isolated from the hairy roots and their regenerants.     

Grid map analysis and its application for detecting vegetation changes in Japan

Abstract. Grid maps are used as a basic vegetation data base in Japan; they are simplified from vector-based vegetation maps. We estimated the frequency error or lack of information corresponding to reduced resolution and examined the reliable limits of this data base. We produced 10 grid maps on five different scales from 50 m to 1000 m using two different methods using both the whole cell (W-method) and only the central circle (C-method) from a vegetation map at scale 1: 25 000. We found that patches larger than the area of a cell on a vector-based map could be kept almost certainly on any map, but many patches of less than the cell size were lost. The number of missing patches with the C-method is fewer at every scale than those with the W-method. Though the value of Morisita's Cλ (p) index showed that the similarity with the original map was high - from the 50-m to the 200-m resolution - it was increasingly lower on the 400-m and 1000-m grid maps. The values of the Shannon index on the original map, 50-m and 100-m grid maps were not different, but they decreased from the 200-m to 1000-m grid maps. Because the vegetation data base of the Japanese Environment Agency used a 1000-m C-method grid map, we found that much information on patches less than 100 ha had disappeared. Information about dominant vegetation or large patches is almost accurate in this data base.     

Microsatellite analysis of pollen flow in Rhododendron metternichii var. hondoense

Microsatellite analysis was used to characterize the patterns of pollen flow in a 150 m × 70 m quadrat containing 18 flowering trees of Rhododendron metternichii Sieb. et Zucc. var. hondoense Nakai. Using six microsatellite genetic markers and exclusion analysis, we determined the paternal trees of 216 seedlings germinated from five fruits produced by four adults. Each fruit was pollinated by a small number of largely adjacent trees, but 20–30% of pollen came from outside the quadrat. Adult trees that produced many flowers had a high self-pollination rate. A directional flow of pollen from late-blooming trees to early ones was observed.