诸葛菜花柄切段和花托离体培养中直接长出小花

在ＭＳ附加ＢＡ的几种培养基上首次从诸葛菜花柄切段和花托部位直接诱导出小花及花枝开花。花发育不正常,无花粉。该花花茎、叶柄、子房等的切段培养仍能再生出小枝,说明成花诱导态是稳定的,不可逆的．     

Morphology,ultrastructure and functional role of antennal sensilla in off-host aggregation by the bed bug,Cimex lectularius

After blood feeding on a host, bed bugs, Cimex lectularius, assemble in aggregation sites away from the host. Off-host aggregation is mediated by a combination of mechanical and chemical stimuli associated with bug feces. Partial antennectomies indicated removal of flagellomeres did not affect aggregation, but removal of the whole pedicel or its distal half significantly reduced (P < 0.01) aggregation, suggesting that sensilla related to off-host aggregation occur on the distal half of the pedicel. Scanning electron microscopy (SEM) revealed that serrated hairs were distributed throughout the pedicel, but newly described smooth hairs were present mainly on the distal half, and a distinct patch of grooved pegs, smooth pegs and immersed cones was present on the posterior edge of the distal half of the pedicel in adults, but not in nymphs. Numbers of different types of sensilla increased significantly during metamorphosis from first instar to adult (P < 0.05), but were similar between genders (P = 0.11) and between females from a laboratory and field strain of bugs (P = 0.19). Transmission electron microscopy (TEM) revealed that cuticular pores were present in the two types of pegs, indicating that the pegs have an olfactory function. The smooth hairs resembled gustatory sensilla previously described in Cimex hemipterus F. The existence of both olfactory and gustatory sensilla on the distal half of the pedicel suggests those sensilla may be the sensory basis of off-host aggregation behavior.     

生长素和赤霉素对离体水仙花茎切段伸长的影响

以离体水仙(Narcissustazettavar.chinensis)花茎切段为材料,通过外源吲哚-3-乙酸(Indole-3-aceticacid,IAA)和赤霉素A3(GA3)处理,结合内源激素分析,研究了这两种激素对水仙花茎切段伸长的影响,以及它们之间的相互作用。结果表明:外源50μmol/LIAA和30μmol/LGA3均能促进花茎切段的伸长,其中IAA的促进作用大于GA3。200μmol/L生长素运输抑制剂2,3,5-三碘苯甲酸(2,3,5-Triiodobenzoicacid,TIBA)和65μmol/L赤霉素合成抑制剂烯效唑(Uniconazole,S-3307)均显著抑制花茎切段的伸长。外源50μmol/LIAA处理明显增加内源GA1 3的含量,是对照的3.40倍;外源30μmol/LGA3处理对内源IAA含量影响不明显,说明IAA对维持花茎切段内源活性GA水平起重要作用,IAA和活性GA共同发挥调控花茎切段伸长的作用。     

Mechanism of signal production in the vibratory communication of the wandering spider Cupiennius getazi (Arachnida,Araneae)

The communication with substrate vibrations produced by vibrations of the body or its appendages is widespread among arthropods, especially among spiders. Its biomechanics, however, is poorly understood. Males of the wandering spider Cupiennius getazi produce such substrate vibrations during courtship by means of dorsoventral movements of their opisthosoma without hitting their dwelling plant.Simultaneous recordings of the plant vibrations (accelerometry), of the opisthosoma movements (laser Doppler vibrometry) and of the electromyograms of the opisthosomal depressor muscle, revealed that the main frequency of the vibratory signal of about 80 Hz originates from the activity of the opisthosomal depressor muscle. The transfer functions of the spider's body show resonances which could amplify the main frequency before it is transmitted into the plant.A low frequency component of the opisthosomal movement (duration c. 0.3 s, displacement c. 6 mm (peak-peak) 30° deflection angle, frequency 10–20 Hz) can be distinguished from a main frequency component (duration c. 0.1 s, displacement c. 0.5 mm 2.5° deflection angle, frequency c. 80 Hz). The main frequency component is superimposed on an upward movement of the low frequency component.     

Bud regeneration from inflorescence explants for rapid propagation of geophytes in vitro

Bulbs, corms and other subterranean storage organs are commonly used as explant source material for the establishment of geophytes in vitro. The inflorescence stalk was found to be a good alternative source of explants to overcome explant contamination originating from underground storage organs. Inflorescence explants of Allium, Dichelostemma, Eucrosia, Gladiolus, Haemanthus, Hyacinthus, Narcissus, Nerine and Ornithogalum were used to establish cultures in vitro. The regeneration potential of the inflorescence was compared with regeneration from bulb twin scales or from apical buds isolated from corms. Gladiolus (Iridaceae) explants isolated from the floral stem just below the expanding florets, still enclosed in the bracts, were highly regenerative in the presence of naphthalene acetic acid (NAA) and kinetin. In the presence of 2,4-dichlorophenoxyacetic acid and benzyl aminopurine (BA) in the medium, explants isolated from the tissue at the junction between the peduncle and the pedicels of a young Nerine (Amaryllidaceae) inflorescence regenerated several buds. The scapes of young unemerged inflorescences taken from sprouting bulbs of Narcissus (Amaryllidaceae), following a 15 °C storage treatment, regenerated buds in the presence of NAA, BA, elevated phosphate and adenine sulfate in the medium. The number of buds regenerated depended on the location on the scape from which the explant was isolated, and on the duration of the 15°C treatment. In Allium (Alliaceae), capitulum tissue between the flower pedicels regenerated buds. Explants excised from the peduncle, as well as the pedicel-peduncle junction of Dichelostemma (Alliaceae), Ornithogalum, Hyacinthus (Hyacinthaceae) and Eucrosia (Amaryllidaceae) regenerated several buds in each type of explant. In the case of Haemanthus (Amaryllidaceae), pedicel-peduncle junction explants regenerated buds only when excised from inner whorl florets. Propagation protocols and the potential use of expediently isolated inflorescence explants for efficient micropropagation of geophytes are discussed. Received: 1 September 1999 / Revision received: 13 December 1999 / Accepted: 13 December 1999     

Carbohydrate and ethylene levels related to fruitlet drop through abscission zone A in citrus

Citrus fruits have two abscission zones (AZ), named A (in the pedicel) and C (in the calyx). Early fruitlet abscission takes place exclusively through AZ A, while at June drop it is progressively inactivated and AZ C begins to operate. In previous work, it has been demonstrated that carbohydrate and ethylene regulate fruit drop through abscission zone C. In this paper, we have analysed the effect of these two factors in developing fruitlets of Satsuma mandarins (Citrus unshiu [Mak.] Marc.) cv. Okitsu to elucidate their involvement on abscission through AZ A. The data indicated that ACC content and ethylene production of fruitlets paralleled abscission rates. Sucrose supplementation increased fruit set, although did not counteract the abscising effect induced by ACC. Branch girdling of terminal fruitlets carrying several leaves significatively reduced ethylene production and abscission rates, and increased sugar content. Pedicel girdling showed the opposite. Taken together, the results revealed that the carbohydrate content may be a biochemical signal involved in the mechanisms controlling abscission through AZ A. The evidence also showed parallelisms between ethylene and its activation. As the induction of higher ethylene levels after the period of AZ A activity, however, was not able to promote fruit drop, it is also concluded that solely ethylene is not sufficient to activate abscission.     

Anatomical Study on the Pedicels of Two Ferns

Pedicel is a stalk connecting sporangia with frond in ferns, and its structure and function are not clear. In this paper, we studied the pedicels of Dryopteris zhuweimingii and Pentarhizidium orientale. We found that the pedicels consist of three lines of cells, and the cell wall can be separated into two layers. The inner layer is secondary cell wall (S1) that spiral and cling to the outer layer. The outer layer is primary cell wall. And when we broke the pedicel into two sections, the inner layer of the cell wall could be pulled out like a spiral belt. This structure may be important to support and protect the sporangia.