831 research outputs found
Grapevine shoot growth and stomatal conductance are reduced when part of the root system is dried
Split-root plants, where the root system was divided between two containers, were used to study the effect of partial drying of the root system on shoot growth and stomatal conductance of grape cultivars Chardonnay and Shiraz (syn. Syrah). When part of the root system was allowed to dry while the other part was well-watered, shoot growth was significantly reduced. Changes in both shoot growth and stomatal conductance in response to half-drying took place in the absence of any change in shoot water status suggesting the involvement of a non-hydraulic signal in mediating this response. Recovery of both shoot growth rate and stomatal conductance appeared to start before rewatering of the dried half of the root system, and coincided with the time when there was no further decrease of soil water content in the dried container. This appears to be first report of a significant decrease in shoot growth in response to partial drying of the root system of grapevines
Osmoregulation in water stressed roots: Responses of leaf conductance and photosynthesis
Kober 5 BB vines were subjected to either moderate and slow soil dehydration or to repeated, severe and rapid stress and irrigation cycles. Moderate soil dehydration to 50 % of the soil water capacity led to a small but significant decrease of the osmotic potential at RWC = 100 %, i.e. to osmoregulation in root tips, but not in other parts of the roots. Osmoregulation was associated with the maintenance of a high water status in the root tips and high rates of leaf gas exchange. In a second experiment three severe and rapid drying cycles led to a decrease of the osmotic potential at RWC = 100 % in root tips as well as in unsuberised and suberised roots, the maximum rate being 2.3 bar. In this experiment osmoregulation in roots contributed to a partial increase of the root water status. The observation that, despite a low soil moisture content, leaf conductance and rate of photosynthesis had slightly recovered is discussed
Primary bud-axis necrosis of grapevines. I. Natural incidence and correlation with vigour
The incidence of primary bud-axis necrosis (PBN) was studied from 1980 to 1985 in Australian vineyards of varying vigour. Fifteen cultivars of Vitis vinifera L. were initially examined for the presence of PBN and, because Shiraz (syn. Syrah) proved to have the highest incidence, subsequent work emphasized this cultivar. Compound buds at nodes 2 to 9 from the base of the shoot (node 9 being the most distal node) were scored for the presence of PBN. PBN was found to be a significant cause of unfruitfulness in the Australian vineyards examined. Incidence was higher in seeded compared with seedless cultivars. Shiraz had the highest incidence but not as great as for other cultivars reported in Israel, Japan, Chile and USA. PBN incidence was highest in the basal nodes of thick shoots, especially if the node bore a lateral shoot. Buds with PBN produced more shoots but fewer bunches. Thinning of shoots ten days before and after flowering increased both shoot vigour and PBN incidence. This association was attributed to the greater vigour per se and not to any change in canopy light environment. PBN-caused loss of primary shoots is concluded to be a major cause of unfruitfulness in basal nodes of grapevine
Partial drying of the rootzone of grape. I. Transient changes in shoot growth and gas exchange
Split-root plants, where the root system was divided between two containers, were used to study the effect of partial drying of the root system on shoot growth and gas exchange of Shiraz (syn. Syrah) (Vitis vinifera), Kober 5 BB (Vitis berlandieri x Vitis riparia) and 110 Richter (Vitis berlandieri x Vitis rupestris). The initial decrease in both shoot growth rate and gas exchange in response to half-drying coincided with the decrease in soil water content of the dried half of the root system. Recovery of shoot function of half-dried grapevines occurred without rewatering of the dried half of the root system, and commenced when there was no further decrease in soil water content. There was no effect of half-drying on leaf water potential at the times of greatest inhibition of shoot growth rate and stomatal conductance relative to control; this suggests the involvement of a non-hydraulic signal originating from the roots in drying soil. Changes in stomatal conductance in response to half-drying were strongly correlated with shoot growth rate
Partial drying of the rootzone of grape. II. Changes in the pattern of root development
Split-root plants, where the root system was divided between two containers, were used to study the effect of partial drying of the root system on gas exchange and root growth of 110 Richter (Vitis berlandieri x Vitis rupestris). The initial decrease in gas exchange in response to half-drying coincided with the decrease in soil water content of the dried half of the root system. Recovery of gas exchange of half-dried grapevines occurred without any further change in soil water content of the dried half of the root system, and coincided with the point at which there was no further decrease in soil water content. For half-dried plants, there was a relative increase in root development in moist soil layers, both in the wet container as a whole or in the lower part of the dry container. Recovery of gas exchange of half-dried plants occurred at the time when there were no more roots dried in the dry container. We propose that, for half-dried plants, the part of the root system in dry soil can survive because water moves from wet roots to dry roots
Loss of Obstetric Services in Rural Appalachia: A Qualitative Study of Community Perceptions
Background: As rural hospitals across the United States increasingly downsize or close, the availability of inpatient obstetric services continues to decline in rural areas. In rural Appalachia, the termination of obstetric services threatens to exacerbate the existing risk of adverse birth outcomes for women and infants, yet less is known about how the cessation of these services affects the broader community.
Purpose: The purpose of this paper is to explain how the loss of local obstetric services affects perceptions of healthcare among multi-generational residents of a remote, rural Appalachian community in western North Carolina.
Methods: An interdisciplinary team of researchers conducted a thematic analysis of health-related oral history interviews (n=14) that were collected from local residents of a rural, western North Carolina community during the summer of 2019.
Results: The closure of a local hospital’s labor and delivery department fostered 1) frustration with the decline in hospital services, 2) perceived increases in barriers to accessing healthcare, and 3) increased medical mistrust.
Implications: Findings suggest that the loss of obstetric services in this rural Appalachian community could have broad, negative health implications for all residents, regardless of their age, sex, or ability to bear children. Community-specific strategies are needed to foster trust in the remaining healthcare providers and to increase access to care for local residents. Results serve as formative research to support the development of interventions and policies that effectively respond to all community members’ needs and concerns following the loss of obstetric services in remote Appalachian communities
VarDict: a novel and versatile variant caller for next-generation sequencing in cancer research
Accurate variant calling in next generation sequencing (NGS) is critical to understand cancer genomes better. Here we present VarDict, a novel and versatile variant caller for both DNA- and RNA-sequencing data. VarDict simultaneously calls SNV, MNV, InDels, complex and structural variants, expanding the detected genetic driver landscape of tumors. It performs local realignments on the fly for more accurate allele frequency estimation. VarDict performance scales linearly to sequencing depth, enabling ultra-deep sequencing used to explore tumor evolution or detect tumor DNA circulating in blood. In addition, VarDict performs amplicon aware variant calling for polymerase chain reaction (PCR)-based targeted sequencing often used in diagnostic settings, and is able to detect PCR artifacts. Finally, VarDict also detects differences in somatic and loss of heterozygosity variants between paired samples. VarDict reprocessing of The Cancer Genome Atlas (TCGA) Lung Adenocarcinoma dataset called known driver mutations in KRAS, EGFR, BRAF, PIK3CA and MET in 16% more patients than previously published variant calls. We believe VarDict will greatly facilitate application of NGS in clinical cancer research
Effect of rootstock on nutrition, pollination and fertilisation in 'Shiraz' (Vitis vinifera L.)
Rootstocks have previously been shown to alter reproductive performance in grapevines. The concentration of nutrients associated with pollination and fertilisation in grapevines such as boron, calcium, zinc and molybdenum were determined in petiole and pollen tissue from vines from a 'Shiraz' (Vitis vinifera L.) rootstock trial at flowering. 'Shiraz' on own roots had a higher calcium concentration in the petioles across the three seasons than the rootstock treatments. This coincided with higher seeded berry number, total number of berries per bunch and berry weight compared to rootstock treatments. '1103 Paulsen' had a significantly higher amount of boron and a lower number of seedless berries and a lower millerandage index (MI). Zinc deficiency was observed for '110 Richter' and '140 Ruggeri' across the three seasons and when zinc was found to be deficient, coulure index (CI) was increased. In the third and final year of the analysis pollen nutrition was incorporated into the analysis. Deficiency of molybdenum in both pollen and petiole analysis resulted in reduced berry weight due to stenospermocarpy or seed shrivel. Rootstocks with the highest number of pollen grains on the stigma also had the highest number of ovules fertilised. Calcium, zinc, boron and molybdenum are nutrients essential for pollination and fertilisation in grapevines and rootstocks were found to affect the sequestration of nutrients which affected reproductive performance.
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