Preliminary observations of tag shedding, tag reporting, tag wounds, and tag biofouling for raggedtooth sharks (Carcharias taurus) tagged off the east coast of South Africa
- Authors: Dicken, Matthew Laurence , Booth, Anthony J , Smale, Malcolm John
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125774 , vital:35816 , https://doi.10.1016/j.icesjms.2006.06.009
- Description: Mark-recapture models do not distinguish how ‘‘deaths’’ accrue to marked animals in the population. If animals lose their tags, then recaptures will be fewer than expected and estimates of survival will be underestimated (Arnason and Mills, 1981; McDonald et al., 2003). Similarly, if the non-reporting rate is unknown and assumed to be negligible, as is the case in some tagging studies (e.g. Cliff et al., 1996, for white sharks Carcharodon carcharias), the probability of capture can be underestimated. The effects of both these problems, inherent in cooperative tagging programmes, lead to too few tagged fish being recovered, with a positive bias on the estimation of population size. These effects are most pronounced when capture probability is low and fewer tags are available for recapture (McDonald et al., 2003).
- Full Text:
- Date Issued: 2006
Comparison of maximal aerobic capacity during running and lifting activities : research article
- Authors: Christie, Candice J , Scott, Patricia A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6745 , http://hdl.handle.net/10962/d1009314
- Description: Acknowledging the specificity of assessing maximal output, the purpose of this paper was to compare the physiological and perceptual responses during a traditional running activity and the common industrial task of lifting; both were taken to maximal effort. The responses of eight male participants were measured during both physical activities separated by at least five days: i) a progressive speed protocol (PSP) involved running on a treadmill at increasing speeds, starting at 10 km.h[superscript -1] and increasing by 1 km.h[superscript -1] every minute until exhaustion; ii) a progressive frequency protocol (PFP) required participants to lift a load of 20% body mass at increasing lifting frequencies, starting at one lift every 10s and reducing the time between lifts by 1s every minute until exhaustion. Physiological responses were measured using a portable on-line system, the K4b[superscript 2] (Cosmed(r)). "Central" perceptual measures were obtained every minute using the rating of perceived exertion (RPE) scale. Results: Responses increased progressively with augmented exercise intensity in both protocols; however, oxygen consumption and peak oxygen values were both lower during the lifting protocol compared to the running protocol. In contrast to the oxygen uptake responses, peak RER values were significantly higher during lifting (mean of 1.32) than running (mean of 1.18), while maximal heart rate and perceptual responses revealed no significant difference between the two protocols. These findings caution against using the 'traditional' treadmill protocol to assess the aerobic capacity of manual labourers involved in lifting, as it is evident that the traditional lower body protocol will indicate a higher capacity than the maximum capacity of an upper body activity, which could lead to manual labourers being taxed beyond acceptable limits.
- Full Text:
- Date Issued: 2005
Evaluating parts-of-speech taggers for use in a text-to-scene conversion system
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Language: English
- Type: Conference paper
- Identifier: vital:6603 , http://hdl.handle.net/10962/d1009323
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
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- Date Issued: 2005
Geography of African development : an alternative curriculum
- Authors: Fox, Roddy C
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6679 , http://hdl.handle.net/10962/d1006666
- Description: The Geography of African Development module is part of a year-long Third Year level geography course on Africa that has been offered at Rhodes University since 2002. The course is an exception to the dominant trend, both locally and internationally, which has witnessed a major decline in the teaching of regional geography and area studies. This paper examines how adopting a constructivist approach to the module's curriculum enabled learners to develop geographical skills at the same time as Africanising the curriculum.
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- Date Issued: 2005
100 years of chemistry at Rhodes University
- Authors: Brown, Michael E , Eve, Desmond John , Kaye, Perry T , Rivett, Douglas E A , Watkins, Gareth M
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6564 , http://hdl.handle.net/10962/d1004123
- Description: The history of Grahamstown is well documented and two books deal with the history of Rhodes University.1,2 Although the Chemistry Department was one of the founding departments, coverage in the official histories is minimal and sometimes inaccurate or misleading. The Rhodes University Centenary is an appropriate time to look back on some of the achievements of the department and some of its graduates over the past 100 years.
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- Date Issued: 2004
Induced ovulation, spawning, egg incubation, and hatching of the cyprinid fish Labeo victorianus in captivity
- Authors: Rutaisire, Justus , Booth, Anthony J
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124789 , vital:35697 , https://doi.10.1111/j.1749-7345.2004.tb00102.x
- Description: Ningu Lubeo victorianus is the only labeine fish within Lake Victoria and its catchment (Greenwood 1966; Reid 1985). This species, once widely distributed in the Lake Victoria basin and supporting a commercial fishery until the late 195Os, has declined due to overfishing (Cadwalladr 1965; Ogutu-Ohwayo 1990; Seehausen 1996). The L. victorianus fishery has not only collapsed but the species has also disappeared from some of its former habitats. Recent surveys in Uganda have only found two distant populations-one in the Sio River on the Uganda-Kenya border (0” I3’53”N, 34”00’30’E), and the second in the Kagera River on the Uganda-Tanzania border (0°56’28.1”S, 3 1’46’ 18”E) (Rutaisire 2003) (Fig. 1). Currently, there is growing interest to breed the fish for wild stock enhancement and culture as a food fish.
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- Date Issued: 2004
Market profiles and trade in medicinal plants in the Lowveld, South Africa
- Authors: Botha, Jenny , Witkowski, Ed T F , Shackleton, Charlie M
- Date: 2004
- Subjects: Kruger National Park
- Language: English
- Type: Article
- Identifier: vital:6625 , http://hdl.handle.net/10962/d1006817
- Description: Rising demand for medicinal plants has led to increased pressure on wild plant populations. This, combined with shrinking habitats, means that many species in South Africa are now facing local extinction. In 1997, a study was initiated to determine the extent of trade in medicinal plants in the South African Lowveld (the low lying plains to the east of the Drakensberg escarpment), and to investigate socio-economic factors influencing trade and resource management. Trade was not as extensive in the Lowveld as in major urban markets such as Durban or the Witwatersrand (Johannesburg and surrounding towns), either in terms of the quantity, number or range of species sold, or the numbers of people relying on the trade for an income. In markets assessed in Mpumalanga Province, 176 species were identified (71% of the vernacular names encountered in the market place), representing 69 plant families. In Limpopo, 70 different species were identified (84% of the vernacular names encountered in the market place), representing 40 families. Imports were significant in Mpumalanga (33% of the plants on offer), mainly from Mozambique. A detrended correspondence analysis showed substantial differences between species traded in Mpumalanga and those sold in Limpopo. There was little variation in the species stocked by vendors in Mpumalanga, regardless of the season, the attributes of the seller, or whether business was carried out in urban or rural areas. In contrast, there was considerable variation in the stock inventories of the Limpopo traders. Despite the lower levels of local trade, increased harvesting pressure is being experienced regionally, to meet demand in metropolitan centres such as the Witwatersrand. This study showed considerable local variation and complexities in the harvesting and marketing of medicinal plants, with both a national and an international dimension. This dual spatial scale presents both opportunities and challenges in the management of these plants, which need to be addressed simultaneously, particularly with respect to research requirements and development of predictive models and capacity. Cooperation in conservation strategies and policies is required at regional, national and international levels, while ensuring that management initiatives take into account local market conditions and the socio-economic realities facing both consumers and those who depend on the trade for their livelihoods.
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- Date Issued: 2004
On becoming an African-Asian English academic at Rhodes University
- Authors: Naidu, Samantha
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:21926 , http://hdl.handle.net/10962/14392 , https://0-www.jstor.org.wam.seals.ac.za/stable/24487641
- Description: preprint , I arrived at Rhodes University English Department with not much more than a passion for literature. During the last fourteen years I have been able to observe the discipline in operation. My perspective has broadened and deepened, taking in the trajectory from Stanley Kidd and the colonial Cambridge practices, and from what might be termed the 'humanist enterprise of English studies', 1 to the white liberalism of Guy Butler in the middle of the twentieth century, then to the present post-apartheid era of humanities cutbacks and increasing commodification of knowledge.
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- Date Issued: 2004
Disturbances of attitudes and behaviours related to eating in black and white females at high school and university in South Africa
- Authors: Edwards, David J A , d'Agrela, A , Geach, M , Welman, Mark
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6246 , http://hdl.handle.net/10962/d1007864
- Description: This paper reports two studies, which contribute to the increasing evidence that the attitudes and behaviours associated with eating disorders, are encountered among both black and white females in South Africa. In Study One, the Eating Disorders Inventory EDI was administered to black (n=39) and white (n=41) female students in Natal. There were no significant differences between black and white on the sub-scales which measure disturbed eating behaviour directly (Drive for Thinness, Bulimia, Body Dissatisfaction). However black respondents scrored higher on Perfectionism, Interpersonal Distrust and Maturity Fears, variables believed to predispose individuals to eating disorders. In Study Two, the Bulimia Test (BULIT) was administered to black and white females at three educational levels. There was no significant effect of Ethnicity, but there was a significant effect of Age: Standard 6 respondents had significantly higher scores than University students. In both studies, Body mass index (BMI) was significantly higher among blacks than whites. In Study One there was no significant correlation between BMI and Drive for Thinness in either blacks or whites. However in Study Two, the correlation between BMI and BULIT full scale was significant in the case of both blacks (r = 0,39; p <,01) and whites (r = 0,38; p<,05). These findings are consistent with those of other recent studies, which find disturbances in eating-related attitudes and behaviour in all ethnic groups in South Africa.
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- Date Issued: 2003
Geography : the state of the discipline in South Africa (2000 - 2001)
- Authors: Fairhurst, U J , Davies, R J , Fox, Roddy C , Goldschagg, P , Ramutsindela, M , Bob, U , Khosa, M M
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6678 , http://hdl.handle.net/10962/d1006659
- Description: The research team presents the findings of a comprehensive investigation into the status and role of Geography as an academic discipline in South Africa. The paper begins by placing the discipline in historical and epistemological context. Extensive and intensive interviews were conducted with geographers at all South African universities and, on a smaller scale, in the workplace. Information was also gleaned from an array of documents. Comments on the characteristics of university departments, general school education, the geography research environment the geographer in the workplace are given. Emerging trends, many of which relate to recent socio-political change, show that contemporary emphasis is on applied geography, specific fields of specialisation, the accommodation of Environmental Science and Environmental Management, skills training and on curriculum development with a marked vocational orientation. As geographers continue addressing national and international environmental and social issues in their professional endeavours, they are alerted to critical concerns voiced with conviction by practising geographers. In the final analysis a positive conclusion is reached and the academic merit and status of the discipline is confirmed.
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- Date Issued: 2003
Pollination success in a deceptive orchid is enhanced by co-occurring rewarding magnet plants
- Authors: Johnson, Steven D , Peter, Craig I , Nilsson, L Anders , Agren, Jon
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6520 , http://hdl.handle.net/10962/d1005949 , http://www.jstor.org/stable/3449962
- Description: It has been debated whether pollination success in nonrewarding plants that flower in association with nectar-producing plants will be diminished by competition for pollinator visits or, alternatively, enhanced through increased local abundance of pollinators (the magnet species effect). We experimentally evaluated these effects using the nonrewarding bumblebee-pollinated orchid Anacamptis morio and associated nectar-producing plants at a site in Sweden. Pollination success (estimated as pollen receipt and pollen removal) in A. morio was significantly greater for individuals translocated to patches of nectar-producing plants (Geum rivale and Allium schoenoprasum) than for individuals placed outside (similar to20 m away) such patches. These results provide support for the existence of a facilitative magnet species effect in the interaction between certain nectar plants and A. morio. To determine the spatial scale of these interactions, we correlated the visitation rate to flowers of A. morio with the density of sympatric nectar plants in 1-m(2) and 100-m(2) plots centered around groups of translocated plants, and at the level of whole meadows (similar to0.5-2 ha). Visitation rate to flowers of A. morio was not correlated with the 1-m(2) patch density of G. rivale and A. schoenoprasum, but showed a significant positive relationship with density of these nectar plants in 100-m(2) plots. In addition, visitation to flowers of A. morio was strongly and positively related to the density of A. schoenoprasum at the level of the meadow. Choice experiments showed that bees foraging on the purple flowers of A. schoenoprasum (a particularly effective magnet species) visit the purple flowers of A. morio more readily (47.6% of choices) than bees foraging on the yellow flowers of Lotus corniculatus (17% of choices). Overall similarity in flower color and shape may increase the probability that a pollinator will temporarily shift from a nectar-producing "magnet" plant to a nonrewarding plant. We discuss the possibility of a mimicry continuum between those orchids that exploit instinctive food-seeking behavior of pollinators and those that show an adaptive resemblance to nectar-producing plants.
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- Date Issued: 2003
Seasonal phenology of the diamondback moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae), and its parasitoids on canola, Brassica napus (L.), in Gauteng province, South Africa
- Authors: Mosiane, S M , Kfir, R , Villet, Martin H
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6856 , http://hdl.handle.net/10962/d1011139
- Description: Canola, Brassica napus L. (Brassicaceae), is a relativelynewcrop in SouthAfrica. Several insect pests, including diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), that attack cruciferous vegetables, also attack canola. The aims of this study were to determine the seasonal phenology of P. xylostella populations on canola, and the composition, relative abundance and seasonal phenology of parasitoids attacking P. xylostella on this crop. Diamondback moth adults were monitored with synthetic sex-pheromone traps. Larval and pupal populations of P. xylostella were monitored weekly for three years at Bapsfontein and Rietondale in Gauteng province. Samples of diamondback moth larvae, pupae and parasitoid cocoons were collected and transported to the laboratory. Parasitoids that emerged were identified and their incidence recorded. Berlese funnel catches were used as an indicator of the accuracy of the visual counts. The infestation level of P. xylostella larvae was high from May to August at Rietondale, while at Bapsfontein it was high from September to December. There was a high correlation (r=0.79, P<0.001) between pheromone trap catches and subsequent larval infestations at Bapsfontein. The pheromone traps indicated that diamondback moth adults were present throughout the year. Berlese funnel catches indicated that a large number of larvae, especially first instars, were overlooked during visual plant scouting. Parasitism rates were often very high, reaching 90–100 %. The following parasitoids were recorded from field-collected P. xylostella: the larval parasitoids Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) and Apanteles halfordi Ullyett (Hymenoptera: Braconidae), the larval/pupal parasitoids Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae), the pupal parasitoid Diadromus collaris (Gravenhorst) (Hymenoptera: Ichneumonidae), and the hyperparasitoids Mesochorus sp. (Hymenoptera: Ichneumonidae) and Pteromalus sp. (Hymenoptera: Pteromalidae). Cotesia plutellae was the most abundant parasitoid throughout the study.
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- Date Issued: 2003
The union movement and South Africa's transition, 1994 - 2003
- Authors: NALEDI
- Date: 2003
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/154168 , vital:39617
- Description: The new government faced enormous challenges when it came into office in 1994. For starters, the outgoing Apartheid leaders had thoroughly plundered the state coffers, awarding themselves and white civil servants massive pensions and 'golden handshakes'. The budget deficit was almost 9% of GDP The country/ had barely three weeks foreign exchange reserves, with a balance of payments crisis looming. The majority of inherited civil servants were generally hostile to the new government. The 'deep structures' of the State — by which I mean the ingrained habits and behaviour — were also generally hostile to the objectives of the democratic State. In addition, poverty levels were very high, and income inequality was among the worst in the world. And, of course, South Africa had the most institutionalised forms of racism in the world, which permeated through every law' and practice.
- Full Text:
- Date Issued: 2003
Metabolic responses to various combinations of gradient, load and marching speed
- Authors: Todd, Andrew I , Scott, Patricia A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6751 , http://hdl.handle.net/10962/d1009331
- Description: This study examined the metabolic cost of South African soldiers carrying loads under various conditions of gradient and marching speed. Thirty-two male soldiers participated in the study. Three speed and load combinations, 4, 5 and 6 km.h[superscript (-1)] carrying of 50, 35 and 20 kg respectively, were imposed, on each of three gradients: -10%, 0% and +10%; a total of nine experimental conditions. Subjects wore standardized military uniforms and breathed into a portable ergospirometer (Metamax) for the duration of each condition. Subjects were required to march for six minutes under each condition, and metabolic responses were monitored during the third and sixth minute of each condition. The metabolic responses to the three level marching conditions showed no significant differences. Marching uphill resulted in a significant increase in metabolic demands under all three speed and load onditions. Downhill marching elicited significant decreases only under the two lighter load conditions. Downhill marching with heavy loads appears to show no reduction in metabolic demands placed on soldiers.
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- Date Issued: 2002
The trade in medicinal plants in the Eastern Cape Province, South Africa
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6512 , http://hdl.handle.net/10962/d1005940
- Description: A study of the trade in medicinal plants in the Eastern Cape Province of South Africa undertook to document the species traded, to determine the quantities harvested annually, and to assess the economic value of the trade. All the participants involved at the different levels of the trade were included in the survey, that is, informal street hawkers, owners of amayeza esiXhosa stores, traditional healers, and consumers of traditional medicines. In total, 282 questionnaires were administered in six urban centres. It was found that poorly educated black middle-aged women of low economic standing dominate the trade. A minimum of 166 medicinal plant species were traded at the study sites alone, providing 525 tonnes of plant material valued at approximately R27 million annually. Plants were harvested from a diverse range of vegetation types including Valley Thicket, Afromontane Forest, Coastal Forest and Moist Upland Grassland, the most frequently sold species differing significantly from those documented in similar studies in other regions. The Forest Biome was the vegetation type found to be most threatened by over-harvesting. Of the species documented, 93% were being harvested unsustainably and 34 species have been prioritised for conservation management.
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- Date Issued: 2002
Design and positioning of controls : the old and the new industrial approaches
- Authors: Dirkse van Schalkwyk, C J
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6750 , http://hdl.handle.net/10962/d1009330
- Description: While copious amounts of research exist with regard to positioning of controls, very little research covers the design shape of the controls. This paper demonstrates the importance of control positioning and design within industrial settings. Furthermore it aims to highlight the changes in industries with regard to control design and positioning. This paper is a review paper and thus much is based on findings by other authors. However, the changes in the industrial practices referred to by the author are from knowledge gained while visiting numerous industries in South Africa.
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- Date Issued: 2001
Preliminary observations on the effects of hydrocortisone and sodium methohexital on development of Sarcophaga (Curranea) tibialis Macquart (Diptera: Sarcophagidae), and implications for estimating post mortem interval
- Authors: Musvasva, E , Williams, K A , Muller, W J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:7075 , http://hdl.handle.net/10962/d1009532
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
- Full Text:
- Date Issued: 2001
Preliminary observations on the effects of hydrocortisone and sodium methohexital on development of Sarcophaga (Curranea) tibialis Macquart (Diptera: Sarcophagidae), and implications for estimating post mortem interval
- Authors: Musvasva, E , Williams, K A , Muller, Wilhelmine J , Villet, Martin H
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6920 , http://hdl.handle.net/10962/d1011898
- Description: Larvae of Sarcophaga (Curranea) tibialis (S. tibialis) were reared at constant temperature on chicken liver treated with a steroid or a barbiturate at concentrations that would be lethal, half-lethal and twice-lethal doses for humans. Trends to greater mortality at higher drug concentrations were not statistically significant. Larvae exposed to either drug took significantly longer to reach pupation compared to those in the control, while larvae exposed to sodium methohexital passed through pupation significantly faster than those in the control. No systematic relationship was found between drug concentration and development time of larvae or pupae. The total developmental period from hatching to eclosion did not differ between treatments, implying that estimates of post mortem intervals- (PMI) based on the emergence of adult flies will not be affected by the involvement of these drugs in a case. On the other hand, anomalous pupation spans may indicate the presence of barbiturates. These findings are compared with patterns found in another fly fed other contaminants.
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- Date Issued: 2001
Re-examining local and market-orientated use of wild species for the conservation of biodiversity
- Authors: Shackleton, Charlie M
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6655 , http://hdl.handle.net/10962/d1007071
- Description: The hypothesis of attaching and realising market values as one means of conserving biodiversity has gained ground over the last decade. This has been challenged recently after examination of a number of case studies, largely from tropical Amazonia, on high value logging, marketing of non-timber forest products, and bioprospecting. The conclusion was that market-orientated conservation has seldom generated the financial returns envisaged, and as such cannot be used as an incentive to prevent land transformation. This paper reviews the basis of the challenge to market-orientated conservation on a number of grounds, drawing on examples largely from southern Africa. It concludes that generalizations from tropical Amazonia regarding the failure of market-orientated conservation are probably premature, and that it should remain an option, amongst a number of options, for conservation of biodiversity. Additionally, the prerequisite criteria identified as necessary to create an enabling framework for the success of market-orientated conservation are insufficient. Case studies are presented where the prerequisites do not apply, yet current extraction for market purposes is sustainable. Other potential prerequisites are also considered. There is a need for multivariate analysis, based on a large sample size drawn from across a range of environments and resources, of which factors are important prerequisites for successful market-orientated conservation, and under which circumstances.
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- Date Issued: 2001
Regulation within the supracellular highway - plasmodesma are the key
- Authors: Botha, Christiaan E J , Cross, Robin H M
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6500 , http://hdl.handle.net/10962/d1005918
- Description: Plasmodesmal connections are unique, highly dynamic intercellular structures that are lined by the plasmamembrane. They are believed to be a vital intercellular communication channel between living cells, linking numbers of living cells into interconnected, highly specialised cellular domains, thus enabling the plant to act as an integrated organism. Their evolution in the higher plant was inevitable. It is accepted that cell heterogeneity rather than cell divergence pressurised developing plant systems along a route that led to the development of intercellular passages and connections. With time these connections have evolved to allow some degree of regulation and traffic control. This paper explores some of the structure/function relationships in plasmodesmata. Attention is focused on the potential role of the neck region of these remarkable structures and discusses models which may explain the processes involved in regulating the movement of substances from cell to cell.
- Full Text: false
- Date Issued: 2001