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991.
G. C. Yencho S. P. Kowalski R. S. Kobayashi S. L. Sinden M. W. Bonierbale K. L. Deahl 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(4):563-574
Glycoalkaloids are quantitatively inherited in Solanum, and in high concentrations they can be toxic to humans. The increased use of wild potato germplasm to improve the pest resistance,
yield, and quality characteristics of cultivated potato may elevate or introduce new, more toxic glycoalkaloids into the cultivated
gene pool. Therefore, it is important to increase our understanding of their inheritance, accumulation, and biosynthesis.
Glycoalkaloids have two basic constituents – a glycosidic grouping and a steroid alkaloid skeleton. Steroid alkaloids are
classified as solanidanes and spirosolanes, of which solanidine and solasodine are, respectively, representatives. RFLP-mapped,
diploid, reciprocal backcross potato progenies involving the parents S. tuberosum and S. berthaultii, which produce solanidine and solasodine, respectively, were analyzed for segregation of the glycoalkaloids solanine, chaconine,
solasodine and solamargine to identify quantitative trait loci (QTLs) for the production of the aglycones solanidine and solasodine.
The F1 clone M200-30 exhibited low to nondetectable levels of solasodine and solanidine, suggesting that expression was controlled
by recessive genes. In a backcross to berthaultii (BCB) and backcross to tuberosum (BCT), several QTLs for the accumulation of solasodine and solanidine were identified. Three QTLs explaining approximately
20% of the variation in solasodine were identified in BCB on chromosomes 4, 6, and 12. Similarly, three QTLs were identified
in BCT on chromosomes 4, 8 and 11, but these accounted for only 10% of the variation observed in solasodine accumulation.
Two QTLs for solanidine were identified in BCT on chromosomes 1 and 4. The QTL located on chromosome 1 was highly significant,
accounting for 17% and 22% of the variation in solanidine accumulation in 1994 and 1995, respectively. This same QTL was also
detected in BCB. The QTLs detected in this study probably represent structural and/or regulatory genes controlling the accumulation
of solasodine and solanidine. Results are discussed in the context of steroid alkaloid accumulation and biosynthesis.
Received: 27 August 1997 / Accepted: 16 March 1998 相似文献
992.
Plant regeneration through organogenesis from callus induced from mature zygotic embryos of loblolly pine 总被引:8,自引:1,他引:7
Mature zygotic embryos from three seed sources of loblolly pine were cultured on callus induction medium containing 10 mg
l–1
α-naphthaleneacetic acid, 4 mg l–1 benzyladenine (BA), 400 mg l–1 casein hydrolysate, and 400 mg l–1 glutamine for 6 weeks. Light-yellow, loose, glossy, globular callus was formed, and the highest frequency was 35.7%. The
highest differentiation frequency of callus on adventitious bud induction medium was 62.1%. After culture of calli with adventitious
buds on elongation medium for 6 weeks, adventitious shoots more than 1.0 cm in height were selected for rooting. On rooting
medium supplemented with 0.1 mg l–1 indole-3-butyric acid, 1 mg l–1 BA, and 0.5 mg l–1 gibberellic acid, the highest rooting frequency of adventitious shoots was 46% in a culture period of 6 weeks. Established
plants survived following transfer to soil at a frequency of 71%.
Received: 14 May 1997 / Revision received: 25 September 1997 / Accepted: 11 October 1997 相似文献
993.
Thirty-two barley cultivars grown in Spain, 18 of the two-row type and 14 of the six-row type, were screened for plant regeneration
from cultured immature embryos. Although there was much variation in regeneration capacity among the cultivars, plants were
obtained from all cultivars except Almunia. No statistical differences were found in the percentage of regeneration between
two- and six-row types. The influence of the auxins 2,4-dichlorophenoxyacetic acid, dicamba, and picloram on the induction
and maintenance of embryogenesis and regeneration capacity after 3–4 months in culture, were evaluated for cultivars Cobra,
Hop and Reinette. Hop had the highest rates of maintenance of embryogenic capacity and plant regeneration. The medium containing
dicamba gave the best embryogenic callus induction, maintenance and regeneration. Five regeneration media, differing in growth
regulators and micronutrient composition, as well as partial desiccation of the calli before regeneration, were tested. The
regeneration medium containing 10 μm copper sulfate gave the best results. Regeneration frequencies after 3–4 months in culture of cultivar Hop were raised from
59.5 to 93.7% in this medium. Silver nitrate and partial desiccation of the calli also enhanced plant regeneration, but the
medium containing 10 μm of silver nitrate reduced root formation.
Received: 30 October 1997 / Revision received: 3 April 1998 / Accepted: 17 April 1998 相似文献
994.
Regenerative ability of somatic single and multiple embryos from cotyledons of Korean ginseng on hormone-free medium 总被引:4,自引:0,他引:4
Cotyledon explants of Korean ginseng (Panax ginseng C. A. Meyer) produced somatic embryos directly on growth regulator-free medium. Somatic embryos developed as either multiple
or single-state forms, depending on the degree of maturity of the cotyledons. Cotyledon explants from midmature zygotic embryos
formed multiple embryos, while cotyledons from fully mature zygotic embryos formed single embryos. Somatic single embryos
regenerated into normal plantlets with both roots and shoots, while multiple embryos did not produce roots but regenerated
only into multiple shoots. In full-strength MS basal medium, the root growth of plantlets derived from single embryos was
weak compared to that of shoots. Deletion of ammonium nitrate from the MS medium promoted the root growth of the plantlets.
The ginseng plants with well-developed shoots and roots regenerated from single embryos were successfully acclimatized in
a greenhouse when they were planted in soil.
Received: 19 July 1997 / Revision received: 6 October 1997 / Accepted: 3 October 1997 相似文献
995.
Louise Morin Alison F. Gianotti Richard Barker Peter R. Johnston 《Biocontrol Science and Technology》1998,8(2):301-311
The development of the pathogenic fungus Fusarium tumidum on gorse ( Ulex europaeus ), a major weed of pastures and plantation forests in New Zealand, was studied under controlled conditions. F. tumidum , like most other foliar fungal pathogens, requires moisture to infect plants. Long, continuous dew periods ( 24 h) after inoculation of plants provided favourable conditions for infection. The fungus, however, also caused severe disease on young plants (2 months old) exposed to two or three 12-h dew periods interrupted by 12-h dry periods. A delay of 24 h before inoculated plants were exposed to dew did not affect the severity of the disease. F. tumidum infected plants over a wide range of temperatures (5-27IC), but more plants were killed as temperatures increased during the initial infection phase. All gorse plants tested (up to 4 months old) were susceptible to the fungus, but younger plants were more easily killed. Nevertheless, the biomass of older plants that were severely diseased but not killed by the fungus was significantly reduced. The effectiveness of F. tumidum in killing plants increased with the density of inoculum sprayed. The fungus applied at a density of 1 106 conidia/ml killed more than 95% of 1.5-month-old plants. This basic knowledge of the F. tumidum -gorse system will assist in the development of a pilot bioherbicide to control gorse and broom ( Cytisus scoparius ), another economically important weed in New Zealand which is also susceptible to the fungus. 相似文献
996.
M. M. M. Miranda M. Pican o J. C. Zanuncio R. N. c. Guedes 《Biocontrol Science and Technology》1998,8(4):597-606
An ecological life table was constructed, aiming to determine the critical stages and key mortality factors of Tuta absoluta (Lepidoptera: Gelechiidae). The total population mortality of this tomato leafminer was 92.3%. During the egg stage the mortality was 58.7%, mainly due to egg inviability. A total of 8.6% egg parasitism by Trichogramma pretiosum (Riley) (Hymenoptera: Trichogrammatidae) and 5.0% egg predation by Xylocoris sp. (Heteroptera: Anthocoridae), Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae) and members of the family Phlaeothripidae (Thysanoptera) was observed. The mortality of the larval stage was 33.0%. This was considered to be the critical stage as it showed the highest apparent mortality (79.8%). Larval parasitism was low (0.1%), and was only found with Goniozus nigrifemur Ashmead (Hymenoptera: Bethylidae). Predators were responsible for 79.4% of larval mortality. Therefore, their attraction to and maintenance in the target area are important management tactics to be considered for T. absoluta control. The first and second instars were considered to be the most critical, and predation by the above mentioned species was the key mortality factor. The mortality at the pupal stage was low (0.6%) and was due to malformation. 相似文献
997.
植物中的细胞程序性死亡 总被引:13,自引:1,他引:12
细胞程序性死亡(PCD)对于维持植物的正常生长发育非常重要,目前已成为植物学研究的一个热点。本文综合评述了近年来植物PCD研究的某些进展,包括植物PCD的特征,植物的营养生长、生殖生长以及与环境互作过程中存在的各种PCD及其证据,植物PCD发生的分子机制及其调控等等。对植物PCD研究中有待进一步解决的问题和可能意义提出了自己的见解。 相似文献
998.
植物根特异性基因表达研究 总被引:3,自引:0,他引:3
植物根中基因表达的调控近几年渐始受到注意,一些分离自植物病原的外源基因启劝子能在植物根中特异性地启动编码基因表达。部分植物基因组基因查明存在根特异表达调控元件和反式作用因子,已分离和克隆了部分未知功能的根特异性表达基因。 相似文献
999.
芥蓝下胚轴离体培养及高频率植株的再生 总被引:7,自引:1,他引:6
三个芥蓝品种下胚轴离体植株再生的条件的研究结果表明:下胚轴切口处可直接诱导出芽,诱导“早花尖叶芥蓝”、“中花尖叶芥蓝”和“迟花尖叶芥蓝”直接出芽的最佳激素组合分别为2.0mgL-1BA,0.3mgL-1NAA+2.0mgL-1BA,0.5mgL-1NAA+2.0mgL-1BA,其相应的芽发生频率分别为84.6%,86.7%,93.3%。诱导芽发生的最适蔗糖浓度是1%。培养基中加入4.0mgL-1AgNO3和500mgL-1MES可显著提高芽再生频率。再生芽在MS附加0.1mgL-1NAA的培养基上诱导生根形成完整植株。离体再生苗与种子萌发实生苗田间生长外形差别不大,但长势稍慢。 相似文献
1000.
Changes in the composition and abundance of grasses and shrubs, soil fertility, and the productivity and nutrition of the grass, Themeda triandra, were examined along an age gradient of Trinervitermes trinervoides mounds occurring in a semi-arid grassland of the Free State, South Africa. The composition and abundance of grasses and shrubs change alongside mounds as they become inactive and then erode away. The pioneer grass, Tragus koelerioides, and the climax grass, Themeda triandra, dominate around active mounds. As the mounds become inactive and erode away, these two grass species are replaced by the subclimax grass, Eragrostis lehmanniana, along with an increase in the cover of the unpalatable shrub, Walafrida saxatilis. Mound soils, in contrast, are sparsely vegetated and only change in composition, and the population abundance of T. triandra, on old active mounds compared to earlier or older mound age states. Soils on eroded mounds are more acidic, and contain higher concentrations of Mg, Ca, N, P, and total exchangeable cations (T.E.C.) than soils occurring 0.5 m from the margins of eroded, inactive and active mounds. A plant bioassay, using Lolium perenne, confirms the higher soil fertility on eroded mounds but also shows significant increases in soil fertility alongside inactive and eroded mounds. Pot experiments show an increase in the production of T. triandra plants grown on soils from eroded mounds, and those occurring alongside inactive and eroded mounds. Foliar protein and nitrogen increase when these plants are grown on soils from eroded mounds. Mounds of T. trinervoides are foci of biotic disturbance because they alter soil resources, and the population abundance and composition of grasses and shrubs in the first metre around their margins. Increases in soil fertility alongside inactive and eroded mounds, and the accompanying increase in the productivity of T. triandra, along with signs of its foliar nutrient enrichment, suggest the removal of this species through preferential grazing by animals as the mounds become inactive and erode away.Plant nomenclature: follows Gibbs Russell, G. E., Reid, C., Van Rooyen, J. & Smook, L. 1985. List of species of southern African plants. Mem. Bot. Surv. S. Afr. 51: 1-152, and Gibbs Russell, G. E., Welman, W. G., Retief, E., Immelman, K. L., Germishuizen, G., Pienaar, B. J., Van Wyk, M. & Nicholas, A. 1987. List of species of southern African plants. Mem. Bot. Surv. S. Afr. 56: 1–270. 相似文献