曼陀罗种子油脂肪酸化学成分研究

以石油醚为溶剂提取曼陀罗种子中的脂肪酸,采用GC-MS技术测定其化学成分,并通过饲料混毒法测定了曼陀罗种子脂肪酸对小鼠的毒性.结果表明,曼陀罗种子中含有23.2%的脂肪酸,其主要化学成分为1,20-二十碳二酸(34.55%)、Crinan-3-ol,1,2-didehydro-,(3à)(13.41%)、8,11-十八碳二烯酸(4.56%)、8,11,14-二十碳三烯酸(Z,Z,Z)(4.39%)、2,3,3-三甲基辛烷(4.35%)、7,10-十八碳二烯酸(3.61%)、亚油酸乙脂(2.64%)、α-亚麻酸(2.34%)、cis-乙酸环己脂-2-丙酸(2.34%)等.采用饲料混毒法对小鼠的毒性测定结果表明,曼陀罗种子脂肪油对小鼠无胃毒作用.研究认为,曼陀罗种子中含有多种对人体有益的活性成分,可作为脂肪酸食用油来源或从中提取对人体有益的活性成分开发利用.     

木本曼陀罗毛状根植株再生体系的建立

建立了木本曼陀罗(Datura arborea L.)毛状根的植株再生体系并对再生植株进行了初步检测.采用"一步法"诱导不定芽的适宜培养基为MS 6-BA 2.0 mg L-1 NAA 0.2 mg L-1;采用"两步法"诱导不定芽时,先在MS 6-BA 4.0 mg L-1 KT 0.5 mgL-1 2.4-D 0.5 mg L-1.上诱导愈伤组织,然后在MS 6-BA 4.0 mg L-1 NAA 0.2 mgL-1上诱导愈伤组织分化不定芽.诱导不定芽的最适宜生根培养基为1/2MS IBA 0.1 mgL-1.用PCR技术从再生植株叶片中得到了rolB、rolC目的基因片段.HPLC检测结果表明毛状根再生植株中莨菪烷类生物碱(Tropme alkaloids,TA)的含量较野生植株有明显的提高.     

曼陀罗植物内生真菌产生物碱菌株的筛选研究

本文从植物曼陀（Datura arborea）中分离得到77株内生真菌。对它们分别进行菌株发酵,发酵产物经乙醇浸提,采用TLC和生物碱显色方法,观察到菌株Ym311977、Ym312023呈生物碱阳性反应。结合HPLC分析结果,表明该生物碱并非曼陀罗植物中的主要生物碱成份。经鉴定,Ym311977属镰孢菌属（Fusarium sp．）,Ym312023属毛壳菌属（Chaetomium sp．）。     

COST OF GLANDULAR TRICHOMES,A “RESISTANCE” CHARACTER IN DATURA WRIGHTII REGEL (SOLANACEAE)

Models regarding the evolution of plant resistance to herbivory often assume that the primary mechanism maintaining resistance polymorphisms is the balance between benefits of increased resistance to herbivores and costs associated with the production of a resistance character. However, rarely has it been demonstrated that genetically based resistance traits are costly. Here, we document costs associated with the production of glandular trichomes, a resistance character in Datura wrightii that is predominantly under the control of a single gene of large effect. In the absence of herbivores, plants with glandular trichomes (sticky) produced 45% fewer viable seeds than plants with nonglandular trichomes (velvety). Although both plant types flowered with similar frequency, sticky plants matured fewer capsules and fewer of their seeds germinated. The fitness difference between the types in herbivore-free conditions was not mitigated by the addition of water, a potentially limiting resource for sticky plants. Under herbivore pressure, there was no significant fitness difference between the types, although the fitness of velvety plants was still higher than that of sticky plants. This occurred even though velvety plants sustained more herbivore damage than sticky plants and were more likely to be attacked by most herbivore species present. The fitness difference between the plant types was especially reduced when herbivore-attacked plants were watered, which indicates that sticky plants may have higher tolerance for damage than velvety plants when supplied with a potentially limiting resource. Yet, the maintenance of a fitness deficit (albeit small and nonsignificant) for sticky plants when attacked by herbivores indicates no net benefit associated with the production of glandular trichomes in this first year of our study. These results add to our current understanding that herbivore resistance characters can be costly and raise the question of how this genetic polymorphism is maintained in wild populations.     

Production ofAgrobacterium-mediated transgenic fertile plants by direct somatic embryogenesis from immature zygotic embryos ofDatura innoxia

This work describes a new method to obtain transgenic somatic embryos fromAgrobacterium-infected immature zygotic embryos ofDatura innoxia. It has several advantages over previous transformation methods such as the absence of a callus phase, an average transformation rate of 76% and a high regeneration frequency. Critical steps for optimal transformation were the embryo stage and a short preculture treatment. The marker gene -glucuronidase and light microscopy were used to identify the competent embryogenic cells which, after transformation, passed through the classical stages of embryo development. The transgenes were transmitted to the progeny in a Mendelian fashion. The plants regenerated via direct somatic embryogenesis were cytologically and morphologically uniform. We also observed that: (1) wounding or wound-induced divisions were not required for zygotic embryo transformation; (2) epidermal cells were competent for both transformation and regeneration; and (3) competency forAgrobacterium infection was developmental stage-specific. This new method should facilitate the development of new strategies to routinely transform recalcitrant plant species.     

Endophytic bacteria from Datura metel for plant growth promotion and bioprotection against Fusarium wilt in tomato

Nine non-pathogenic bacterial isolates, recovered from Datura metel organs and able to colonise the internal stem tissues of tomato cultivar Rio Grande, were screened for their ability to suppress tomato Fusarium wilt disease caused by Fusarium oxysporum f. sp. lycopersici (FOL), and to enhance plant growth. S33 and S85 isolates tested were found to be the most effective in decreasing Fusarium wilt severity by 94–95% compared to FOL-inoculated and untreated control. A significant enhancement of growth parameters was recorded on tomato plants inoculated or not with FOL. Both isolates were characterised and identified using 16S rDNA sequencing genes as Stenotrophomonas sp. str. S33 (KR818084) and Pseudomonas sp. str. S85 (KR818087). Screened in vitro for their antifungal activity towards FOL, these isolates led to 38.7% and 22.5% decrease in pathogen radial growth and to the formation of an inhibition zone of 12.75 and 8.37?mm respectively. Stenotrophomonas sp. str. S33 and Pseudomonas sp. str. S85 were found to be chitinase-, protease- and pectinase-producing strains but unable to produce hydrogen cyanide. Production of indole-3-acetic acid-like compounds, phosphate solubilising ability and pectinase activity were investigated for elucidating their plant growth-promoting traits and their endophytic colonisation ability.     

Prediction of cotton leaf curl virus disease and its management through resistant germplasm and bio-products

Cotton leaf curl virus disease reduces the cotton yield significantly every year and is transmitted by Bemisia tabaci. The study was designed to evaluate 15 varieties/lines against the disease. Multiple regression analysis was performed based on a-biotic environmental variables (maximum air temperature, minimum air temperature, relative humidity and rainfall) to predict disease incidence and its vector (Bemisia tabaci). Two bio-products were evaluated against the whitefly population to control the disease. Out of 15 cotton varieties/lines, no one was found highly resistant against the disease. Five varieties/lines (BT BT-980, BT-457, KIRAN, BT-666 and SLH-BT-6) exhibited moderately resistant response. Maximum air temperature (34–35.5 °C), minimum temperature (25.75–26.25 °C), relative humidity (64.14–66%), rainfall (1–2 mm) and wind speed (5.50–5.75 Kmh^?1) favoured the disease development. Maximum whitefly population was favoured by maximum air temperature from 34–35.5 °C, 25.8–26.2 °C minimum air temperature, 64.14–66% relative humidity, 1–2 mm from rainfall and 5.50–5.75 Kmh^?1 wind speed. Datura stramonium was found more effective as compared to Aviara (Homoeopathic) but not from the positive control (Acetamiprid).     

Tropane alkaloid production inDatura stramonium root cultures

Summary Tropane alkaloid production was studied in different root cultures ofDatura stramonium. Cultured roots were obtained with 10⁻⁶ M of indolbutyric acid. Their doubling times were from 6 to 19 days. Hyoscyamine content varied from 0.17 to 0.62% dry weight, and scopolamine content from 0.08 to 0.33% dry weight, depending on the lines. A comparison of the bioproductivity of these compounds in the pot-grown plant roots showed that it was two to three orders lower than cultured roots, and it increased one order of magnitude considering the productivity on the whole plant. Bioproductivity, growth capacity and alkaloid production stability during subsequent transfers (more than 2 yr) are reported. Only one root line (N5) showed excretion of the alkaloids to the culture medium. Characterization of three selected lines (N1, N5, and N9) showed that the highest alkaloid production is reached at the stationary phase of growth, with the exception of line N9.     

Genetic stability of hairy root cultures of Datura stramonium

The karyotypic status of three root lines, transformed with Agrobacterium rhizogenes, versus a non-transformed root line of Datura stramonium, as well as grown plants (control), was investigated. In the transformed cultures, the karyotype as well as the number of chromosomes (2n = 24) remained the same as in the control plants. In the normal root line there were clear differences at a morphological level despite showing the same chromosomic number (2n = 24) at a high frequency. The existence of aneuploids (2n = 2n ± x) and tetraploids (2n = 4x = 48) was also observed in the latter. The frequency of chromosomic alterations was very low in all the cultures. Cytogenetic analysis of the transformed root cultures of D. stramonium reported here shows a great chromosomic stability, which is not the case with normal root cultures. This revised version was published online in June 2006 with corrections to the Cover Date.     

No benefit of glandular trichome production in natural populations of Datura wrightii?

Populations of Datura wrightii vary in the frequency of plants that produce glandular trichomes, a resistance trait under the control of a single gene. Such variation may be maintained if the production of glandular trichomes is costly in the absence of herbivory, and if selection imposed by herbivore communities varies spatially or temporally. Here, we document costs in the presence of herbivory for established glandular plants relative to established non-glandular plants growing in natural populations from coastal mountain, Riversidian sage scrub, and Mojave desert habitats in southern California. Damage caused by the herbivore community varied spatially, with significant differences in herbivore-specific damage between plants of the two trichome types and among populations within habitats, although not generally among habitats. Plants with greater canopy size and canopy persistence had higher viable seed production than smaller or more damaged plants, but this relationship was statistically significant only for non-glandular plants. However, the relationship between viable seed production and canopy persistence became significant for glandular plants when damage caused by sap suckers, which do not remove leaf area, was pooled with undamaged leaf area. The high cost exhibited by glandular plants leads us to predict that in the absence of any additional, unknown benefits of producing glandular trichomes, the frequency of these plants should decline in all natural populations of D. wrightii. Received: 13 July 1999 / Accepted: 28 September 1999