The occurrence of transgenic herbicide-resistant oilseed rape (Brassica napus) in ruderal (non-crop disturbed) areas has not been investigated previously in Canada. The primary objective of this study was to document their occurrence in two main ruderal areas (along railways and roads) in the province of Saskatchewan, where half of all oilseed rape is grown, and at the port of Vancouver, British Columbia on the west coast of Canada, where most oilseed rape destined for export is transported by rail. During the 2005 growing season, leaf samples of oilseed rape plants were collected at randomly-selected sites along railways and roads across Saskatchewan ecoregions and at Vancouver; infestation area, density, and plant height of oilseed rape were measured at each site. The presence of the glyphosate and glufosinate resistance traits was determined using test strips. The infestation area of oilseed rape, averaged across 155 sampled sites in the Saskatchewan survey, was markedly smaller in populations along railways than roads; in contrast, infestation area averaged across 54 sites in the Vancouver survey was greater for populations along railways than roads. In both surveys, mean plant density was greater for populations found along railways than roads. Two-thirds of oilseed rape plants sampled across Saskatchewan ecoregions and at Vancouver were transgenic, although the relative proportion of plants with the glyphosate or glufosinate resistance trait varied between surveys. Frequency of occurrence of transgenic plants in ruderal areas was similar to the proportion of the oilseed rape area planted with transgenic cultivars in the recent preceding years. A single transgenic B. rapa x B. napus hybrid was found along a road in Vancouver, confirming the relatively high probability of hybridization between these two Brassica species. With current control measures, transgenic oilseed rape populations may persist and spread in these ruderal areas.

1. The behaviour of nectar-collecting Bombus hypocritu sapporensis Cockerell queens was observed on a population of a spring ephemeral plant Corydulis umbiguu Cham. et Schlecht.2. Daily patterns of activity and behaviour changed with the progress of flowering. Activity peaked shortly before sunset early in the flowering season but approximately at noon towards the end of flowering. In the peak flowering period the queens tended to visit nearby plants and to change direction often, whereas early or late in the flowering period they flew further between visits and were less likely to change direction.3. Each plant was visited 0 to 24 times (mean 9.4 +SD 5.2) by the queens during the whole flowering season.4. The queens collected nectar, rarely through the front of the flowers but mostly through the spurs perforated by themselves or predecessors. At the beginning of the flowering season the illegitimate foragers often visited the front of the flowers before moving to the spurs; later, most queens quickly learned to land directly on the spurs. 5. Even the 59.7% of plants that were visited only by illegitimate foragers set seeds. Close observation confirmed that the illegitimate foragers opened the inner petals enclosing anthers and stigma frequently when visiting the front of the flowers before robbing, or occasionally when walking about on the flowers or collecting nectar through the perforated spurs.

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The process and mechanisms of spatio‐temporal changes in growth, population structure, as well as various yield and reproductive components of a population of an amphicarpic annual, Polygonum thunbergii (Polygonaceae), with two reproductive systems (aerial chasmogamous flowers and subterranean cleistogamous flowers) along an environmental gradient (light, moisture and soil nitrogen levels) were investigated in the field. The results clearly demonstrate that growth and allocation patterns, population structure, and reproductive output of individuals changed sharply along the environmental gradient in response to seasonal and spatial changes in resource availability. Models predicted that light conditions bring about one‐sided competition, whereas nutrient conditions in the soil engender two‐sided competition. As expected, the degree of one‐sided competition was prominent in the case of a planophile, Polygonum thunbergii. Allocation patterns, seed outputs, individual seed size as well as relative energy costs of chasmogamous and cleistogamous seed as affected by light and nutrient levels were also critically analyzed. The most noteworthy finding was that the size of chasmogamous seeds sharply decreased in response to a decrease in the light regime, while cleistogamous seed size remained constant along the gradient. However, relative cost of both chasmogamous and cleistogamous seeds sharply increased with decrease in the light level, reflecting different degrees of environmental stress, biotic interference, or both.

Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006–2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment.

Canopy shade reduces light quantity and quality, and hence affects plant growth and development. In order to investigate the respective effects of varying light quantity and quality on a clonal plant Cyperus esculentus, a controlled-environment study was conducted in growth chambers, in which four light environments were created using either green filters or neutral shade cloth. The experiment was harvested five times at approximately 2-week intervals after transplanting. Results revealed that numbers of ramets and tubers, total leaf area, and the branching index of rhizomes were affected only by light quantity, while leaf and sheath lengths, leaf area ratio, leaf blade weight fraction, sheath weight fraction, stalk weight fraction, internode length of rhizomes, number of rhizomes, node number of rhizomes, total dry weight, percentage of flowering ramets, and flower weight fraction were affected by both light quality and quantity. Light quantity or quality had little influence on rhizome length, biomass allocation to rhizomes and tubers, and the ratio of tuber number to rhizome number. It is concluded that light quality and quantity had significant effects on growth, sexual reproduction (i.e. the percentage of flowering ramets and sexual reproductive allocation) and associated traits, but did not affect relative vegetative reproduction or storage (i.e. the tuber weight fractions and the fraction of rhizomes differentiated into tubers) in C. esculentus. Therefore, light quantity and quality have differential effects on the growth and morphology of C. esculentus.

The safety and impact on the environment of transgenic crops are important issues, and studies have shown that pollen from transgenic Bt (Bacillus thuringiensis) corn (Zea mays L.) may kill nontarget insects. To develop an algorithm for assessing the environmental effect of transgenic crops, we arranged a field experiment in Tsukuba, Japan. Pollen dispersal and deposition were measured inside and outside a cornfield throughout the flowering period. Weather conditions such as wind speed and direction were measured at the same time. Pollen dispersal peaked 1 week after the start of flowering and continued for 12 days thereafter. The variation in daily pollen dispersal was similar at all observation points. Both pollen dispersal and deposition decreased exponentially with distance from the cornfield on all days. We estimated potential pollen deposition with a quasimechanistic model that incorporates the effects of wind direction, wind speed, and flowering intensity. The daily potential deposition was summed over the flowering period, and then the relationship between distance from the cornfield and the integrated potential deposition was estimated. It was possible to show the effective area of the environmental risk zone posed by genetically modified pollen by combining the distance/deposition relationship with the dose/response relationship derived from a laboratory assay. The algorithm described here can be applied to various wind-pollinated plants to estimate both potential and integrated pollen deposition.

Concern has been raised about the importation and transportation of GM B. napus, because feral herbicide-tolerant GM B. napus plants have been found growing around some major seaports in Japan. We should monitor the persistence of these feral B. napus populations including the herbicide-tolerant GM cultivars to prevent the negative impact of GM B. napus on native plant communities. In this study, we examined the plant numbers and the persistence of the B. napus at 19 sites around the Kashima seaport in Japan once a month from July 2004 to December 2005. In the results, the plant numbers ranged from 0 to 202 depending on the sites and/or the seasons. Out of 19 sites, we observed the seed dispersals of B. napus plants at only four sites. Of these four sites, we finally confirmed the self-sustainment of B. napus populations at two sites. Many plants growing at most of the sites disappeared before flower budding due to frequent human disturbances.