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101.
A 2-year commercial-scale study was conducted to qualitatively evaluate the effect of different insecticide treatment regimes on the predator complex attacking Bemisia tabaci (Gennadius) in cotton. In 1996 three insecticide regimes were compared: a rotation of conventional broad-spectrum insecticides or one of two different regimes based on the initial use of the insect growth regulators (IGRs), buprofezin and pyriproxyfen. In 1997 the same three regimes plus an untreated control were compared; split-plots were sprayed once for Lygus hesperus Knight control using a broad-spectrum insecticide. Relative feeding activity for each predator species was compared between treatment regimes by analyzing the gut contents of predators for the presence of whitefly remains using a whitefly-specific enzyme-linked immunosorbent assay (ELISA). The ELISA results were combined with predator density data to obtain a qualitative pesticide impact index for each predator group. In total, we analyzed the gut contents of 32 262 field-collected predators, representing nine different taxa. Of these, Pseudatomocelis seriatus (Reuter), Spanagonicus albofasciatus (Reuter), and spiders consisting primarily of Misumenops celer (Hentz) are shown to be whitefly predators for the first time. Predator populations were usually reduced in plots that received applications of broad-spectrum insecticides for B. tabaci and L. hesperus control, but there were few treatment differences in the proportions of predators containing whitefly remains in their guts. However, the feeding activity of certain predator species in fields sprayed with broad spectrum insecticides was significantly reduced compared with those in IGR-based and control treatments. Overall, insecticide regimes using IGRs were less lethal to the whitefly predator complex than regimes consisting of only conventional, broad-spectrum insecticides, but differences in predator feeding activity on whitefly between the various insecticide treatment regimes were minimal. 相似文献
102.
Summary Stem segments from apical shoot tips of Polygala myrtifolia were used as primary explants to establish in vitro cultures. Axillary shoots produced on non-contaminated explants were excised and recultured in the same medium to increase
the stock of shoot cultures. Equal molar concentrations of five cytokinins [2-isopentenyladenine, kinetin, zeatin, N
6-benzyladenine (BA), and adenine] were tested for ability to induce axillary shoot development from double-node stem segments.
The highest rate of axillary shoot proliferation was induced on Murashige and Skoog agar medium supplemented with 1.8 μM BA. Seven indole-3-acetic acid (IAA) concentrations (0, 2.9, 5.7, 8.6, 11.4, 14.3, 17.1 μM) were tested to determine the optimum conditions for in vitro rooting of microshoots. Up to 72% of the microshoots rooted with 14.3 μM IAA. Other auxins tested, α-naphthaleneacetic acid and indole-3-butyric acid, were less effective than IAA in inducing adventitious
root formation. All rooted plantlets having more than three roots were successfully established in soil. 相似文献
103.
104.
Multiple shoots of Spilanthes acmella Murr. were induced from hypocotyl segments obtained from 1-week-old seedlings on Murashige and Skoog's (MS) medium containing benzyladenine (BA), isopentenyl adenine, and naphthaleneacetic acid (NAA). High frequency shoot proliferation (95 %) and maximum number of shoots per explant (10 ± 0.6) were recorded with 0.5 mg dm–3 BA in combination with 0.1 mg dm–3 NAA. A proliferation was achieved by repeatedly subculturing the nodal segments on shoot multiplication medium. About 95 % of the in vitro shoots developed roots after transfer to half strength MS medium containing indole-3-butyric acid (1.0 mg dm–3). 95 % of the plantlets were successfully acclimatized and established in soil. Transplanted plantlets showed normal flowering without any morphological variation. 相似文献
105.
Lavandin (Lavandula dentata) axillary buds were grown in Linsmaier-Skoog (LS) medium solidified with 10 % bactoagar (control) and supplemented with 0.1 mg dm–3 benzyladenine (BA), 0.1 mg dm–3 indolebutyric acid (IBA) or both plant growth regulators. In the studied conditions the axillary buds developed into plantlets. The addition of BA inhibited the formation of glands by 44 % as compared with the control plantlets and also inhibited their development: these plantlets had the highest number of unbroken glands (in pre-secretory state) when compared with plantlets grown in the other conditions. The presence of BA stimulated chloroplast formation, and increased the content of essential oils by 150 % with respect to the control plantlets. It also increased their secretion, and the number of lipid droplets in the chloroplasts, cytosol and plasmalemma. On the contrary, the presence of IBA decreased the essential oil concentration in plantlets by 31 % when compared with the control ones and inhibited their secretion capacity. 相似文献
106.
We review the role of protein kinases in plant hormone-mediatedsignalling, nutrient signalling and cell cycle control and in the crosstalkbetween these different contributors to plant growth regulation. The areas ofhormone-mediated signalling covered include ABA-mediated responses to osmoticstress, wounding and pathogen attack, as well as ethylene and cytokininsignalling pathways. These areas involve members of several major protein kinasefamilies, including the SNFl-related protein kinase-2 (SnRK2) subfamily, thecalcium-dependent protein kinase (CDPK) family, the mitogen activated protein(MAP) kinase family, the glycogen synthase kinase (GSK)- 3/shaggy family and thereceptor-like protein kinase (RPK) family. In the section on nutrient signallingwe review the role of SnRK1 protein kinases in the global regulation of carbonmetabolism, including aspects of sugar sensing and assimilate partitioning, andwhat is known about nitrogen and sulphur nutrient signalling. In the cell cyclesection, we summarise progress in the elucidation of cell cycle control systemsin plants and discuss the interaction between cell cycle control anddevelopment. We expand further on the hypothesis of crosstalk between differentsignalling pathways in a separate section in which we discuss evidence forinteraction between plant growth regulators and the cell cycle, betweendifferent nutrient signalling pathways, between nutrient and cell cyclesignalling and between nutrient and ABA signalling. 相似文献
107.
Thidiazuron Induced Multiple Shoot Induction and Plant Regeneration from Cotyledonary Explants of Mulberry 总被引:4,自引:0,他引:4
T. Dennis Thomas 《Biologia Plantarum》2003,46(4):529-533
A rapid micropropagation protocol through induced multiple shoots from the cotyledonary explant of mulberry (Morus alba L) is described. The highest number of shoots (20.3) was obtained when explants from 14-d-old embryos were cultured on Murashige
and Skoog (MS) medium supplemented with 7 μM thidiazuron for 45 d. Of the three cultivars used, cv. S-36 was the best followed
by cv. K-2 and S-1. The shoots were transferred to MS medium supplemented with 5 μM 6-benzylaminopurine for elongation. The
elongated shoots were rooted on half strength MS medium containing 1 – 7 μM indole 3-butyric acid or 1-naphthalene acetic
acid. The rooted plants were transplanted to soil with 90 % success. The emerged shoot primordia probably initiated from the
pre-existing meristems since the shoot bud show definite vascular connection to the major vascular tissue.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
108.
The seeds of Paris polyphylla var. yunnanensis are deeply dormant, and they remain dormant for 18 months or longer in their natural environment. Periodic exposure of the seeds to a low-temperature of 4 °C broke the dormancy in about 16 weeks (112 days). The most effective temperature stratification scheme was an interval of 14 days at 4 °C and 14 days at 22 °C. Both GA3 and ethephon significantly enhanced the germination rate during the stratification treatment. The seed coat, particularly the mesophyll outer layer of the seed coat, strongly inhibited the germination. With removal of the seed coat and exposure of the uncoated seeds to 600 mg/l GA3 for 48 h before the temperature stratification of 14 days at 4 °C and 14 days at 22 °C for 112 days, a germination percentage as high as 95.3% of the seeds was attained in about 160 days. 相似文献
109.
A simple protocol for mass multiplication of Crataeva nurvala, a medicinal tree, from seedling-derived explants is described. Six different types of explants (cotyledonary nodes, epicotyl
nodes, hypocotyl segments, first pair of leaves, cotyledons, and root segments) developed shoots on Murashige and Skoog's
(MS) basal medium or the same supplemented with different concentrations of 6-benzylaminopurine (BAP). Among the explants
tested for caulogenic potential, only the epicotyl and cotyledonary nodal explants developed shoots on MS basal medium, while
on BAP (0 – 2.0 mg dm−3) adjuvated media all the explants exhibited caulogenesis. The optimum concentration of BAP varied for these explants. The
shoots could be rooted on half strength MS with 0.02 mg dm−3 α-naphthalene acetic acid to get plants, which have been transferred to soil. The explants from in vitro regenerated shoots also possessed a similar caulogenic potential.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
110.
Optimized somatic embryogenesis in Pinus strobus L. 总被引:5,自引:0,他引:5
Krystyna Klimaszewska Yill-Sung Park Cathy Overton Ian Maceacheron Jan M. Bonga 《In vitro cellular & developmental biology. Plant》2001,37(3):392-399
Summary Somatic embryogenesis (SE) initiation in Pinus strobus was optimized by the manipulation of plant growth regulator (PGR) concentrations in the culture medium. Modified Litvay medium
(MLV) of Litvay et al. (1985) supplemented with lower than routinely used PGR concentration increased initiation of established
embryogenic cultures from approximately 20 to 53%. The original developmental stage of zygotic embryos had a pronounced effect
on the SE response. The optimum stage was the pre- to shortly post-cleavage stage. A substantial genetic influence on initiation
of SE was indicated by a significant variance component due to families. Genotype X collection date and genotype X media interactions
had large effects on initiation of SE. The PGR levels in the culture medium prior to maturation had a significant effect on
subsequent production of mature somatic embryos. Embryogenic tissue initiated and proliferated on medium with a low level
of PGR consistently produced a high number of somatic embryos, indicating that optimized initiation protocol also enhanced
somatic embryo production. Somatic embryos of 93 embryogenic lines (representing five families) that were initiated on media
with different PGR concentrations were converted to plants at an overall frequency of 76%, and grown in the greenhouse. With
these improved protocols, application of P. strobus SE in commercial clonal forestry is feasible as an alternative to traditional breeding and reforestation. 相似文献