光质对黄瓜及番茄愈伤组织培养中分化和有关酶的影响

黄瓜及番茄愈伤组织培养过程中的分化和生理生化过程明显地受到光质处理的影响,它们的过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)的活性变化与组织及器官的分化都有一定的相关性。黄瓜愈伤组织培养中POD及PAL的第3个活性峰的出现与芽的分化一致,红光与绿光抑制黄瓜愈伤组织培养中芽的分化,不出现第3个活性峰。两种材料培养后培养物的生物重量在不同光质下也有明显差异,但含水率之间无差异。     

Haploid callus and regeneration of plants from anthers of Digitalis purpurea L.

Summary Production of callus from anthers of D. purpurea was obtained on several basal media supplemented with various amounts of auxins. Chromosome counts showed that the callus produced was haploid when the anthers 1) were of a dark-brown to black color, and 2) were cultured in the late tetrad stage of microspore development. Subsequent differentiation to plants at high frequencies was possible only 1) when the anthers had been cultured on the medium of Nitsch and Nitsch (Science 163, 85–87; 1969) supplemented with 5 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), 2) when the callus was transferred to the same medium but without 2,4-D, and 3) when it was cultured under continuous light from fluorescent lamps. Proliferation of the callus and regeneration of plants did not diminish through as many as 20 subcultures. The high frequency of regenerates permits the propagation of a distinct geno-type to a virtually unlimited number of plants. Diploid plants were obtained when the anthers had been cultured in the dark. Tetraploid plants were regenerated by callus from anthers which had been cultured in light. When the time of 2,4-D treatment was shortened a few haploid plants were produced which however did not survive transfer to soil. Cytological observations demonstrated that regeneration started from haploid callus, leading to intermediate degrees of ploidy and finally to diploid plants. Most of the regenerated plants were euploid and flowered and fruited normally under greenhouse and field conditions. If the anther-derived callus was cultured on the medium of Nitsch and Nitsch supplemented with 2.2 mg/l kinetin, plants regenerated only under photoperiodic conditions of 16 h light at 28° and 8 h dark at 20° but the survival was lowered to one third. These plants had a different leaf and flower morphology as compared to the control without kinetin and to the starting material, but their progeny was again essentially normal.     

Differential solasodine accumulation in photoautotrophic and heterotrophic tissue cultures of Solanum laciniatum

Foliage from a Solanum laciniatum plant contained 7.64 mg solasodine per g dry weight. In contrast, leaf-derived callus cultures incubated under light yielded only 0.09 mg/g solasodine. A similar low level was recovered from shoots regenerated from this callus and cultured under heterotrophic conditions. However, shoots cultured photoheterotrophically or photoautotrophically yielded solasodine concentrations approaching those of field grown plants. Solasodine biosynthesis in S. laciniatum is therefore promoted by actively photosynthesising chloroplasts, and cell cultures yield only low solasodine levels as a consequence of their heterotrophic mode of nutrition.     

Photoinduced reactivation of photosystem II in Chlorella after prolong incubation without light

The light-dependent reactivation of photosystem II in Chlorella pyrenoidosa Chick, CALU-175 cells, inactivated with supraoptimal temperatures (40-43 degrees C) in the dark or during heterotrophic growth was studied. It was shown that the inactivation of photosystem II after incubation in the dark at 41-42 degrees C, which showed up in the suppression of relative yield of variable chlorophyll fluorescence Fv due to an increase in yield F0 could be completely reversed by light. The inactivation of photosystem II at 43 degrees C in the dark could not be reversed by subsequent irradiation. In this case, the suppression of Fv/Fm was related not only to the growth of F0 but also with the decrease in Fm. The light dependences of the rate and extent of reactivation of yield Fv after heterotrophic growth or incubation of chlorella at 41 degrees C in the dark completely coincided. The full light-induced reactivation of photosystem II took place as the rate of photoinduced electron transport reached the rate of nonphotochemical reduction of plastoquinone in the dark. These results suggest that the light-reversed inactivation of photosystem II after heterotrophic growth or incubation at 41 degrees C in the dark is due to the redox-interaction of the primary quinone acceptor with plastoquinone reduced by the electron flux from the substrates of chlororespiration.     

<Emphasis Type="Italic">Aspergillus vadensis</Emphasis>, a new species of the group of black Aspergilli

A strain from the group of black Aspergilli was analysed in detail to determine the species to which it belongs. A detailed analysis of morphology, RFLP patterns and metabolite profiles was carried out. In addition, a phylogenetic tree was constructed for the black Aspergilli using the ITS and the -tubulin sequences of the individual strains. The new species differs by its poor growth on glycerol and galacturonate and its unique extrolite profile consisting of aurasperone B, nigragillin, asperazine and kotanins. RFLP analysis using three genes as probes also resulted in a unique pattern. These data indicate that the strain was closely related but not identical to Aspergillus foetidus, Aspergillus niger and Aspergillus tubingensis. It was therefore designated as a novel species and named Aspergillus vadensis.     

Photoautotrophic growth of soybean cells in suspension culture: I. Establishment of photoautotrophic cultures

Highly chlorophyllous photomixotrophic callus was visually selected from callus originating from soybean (Glycine max (L.) Merr. var. Corsoy) cotyledon. Suspension cultures initiated from this callus became photoautotrophic under continuous light with an atmosphere of 5% CO₂ (balance air). Dry weight increases of 1000 to 1400% in the 2-week subculture period have been observed. The cellular Chl content ranged from 4.4 to 5.9 micrograms per milligram dry weight which is about 75 to 90% of the Chl content in soybean leaves under equivalent illumination (300 micro-Einsteins per square meter per second).

No growth can be observed in the dark in sucrose-lacking medium or in the presence of 0.5 micromolar 3-(3,4-dichlorophenyl)-1,1-dimethylurea, a concentration which does not inhibit heterotrophic growth (on sucrose). Photoautotrophic growth has an absolute requirement for elevated CO₂ concentrations (>1%). During the 14-day subculture period, growth (fresh weight and dry weight) is logarithmic. Photosynthesis quickly increases after day 4, reaching a peak of 83 micromoles CO₂ incorporated per milligram Chl per hour while dark respiration decreases 90% from day 2 to day 6. The pH of the growth medium quickly drops from 7.0 to 4.5 before slowly increasing to 5.0 by day 14. At this pH range and light intensity (200-300 microEinsteins per square meter per second), no O₂ evolution could be detected although at high pH and light intensity O₂ evolution was recorded.

     

番茄叶片光合作用对快速水分胁迫的响应

采用聚乙二醇(PEG 6000)溶液控制番茄根际水势和叶片离体的方式设置了水分胁迫处理,测算了光合诱导过程中净光合速率、暗呼吸速率和CO₂补偿点等光合参数的变化.结果表明： 在1000 μmol·m^-2·s^-1光诱导下,水分胁迫处理的番茄叶片净光合速率(P_n)达到最大值所需时间缩短为对照的1/3,气孔导度(g_s)快速增大为对照的1.5倍.水分胁迫处理的番茄叶片光饱和点(LSP)比对照降低了65%～85%,而光补偿点(LCP)比对照增加了75%～100%,缩小了番茄叶片利用光能的有效范围.水分胁迫处理的番茄叶片最大光合能力(A_max)低于对照40%以上,暗呼吸速率(R_d)增大了约45%.可见,快速水分胁迫处理使番茄叶片气孔迅速开放,光合诱导初始阶段消失.水分胁迫导致植物利用光能的效率和潜力降低是植物生产力下降的重要原因,而气孔调节是番茄适应快速水分胁迫的重要生理机制.     

Changes of the diurnal and circadian (endogenous) mRNA oscillations of the chlorophyll a/b binding protein in tomato leaves during altered day/night (light/dark) regimes

Characteristic steady-state mRNA level oscillations were monitored for the chlorophyll a/b-binding (cab) protein in tomato plants grown under the natural day/night (light/dark) regime as well as under constant environmental conditions. This typical expression pattern was altered when plants were transferred to different light/dark regimes. For example, by shifting the light phase by six hours, a change of the time points of maximum and minimum of expression level was monitored, while the principal oscillation pattern remained the same. It appeared that the transition from dark to light is involved in determining the time points of minima and maxima of mRNA accumulation.After exposing tomato plants to an abnormal light/dark periodicity (e.g. six hours of alternating light/dark) an altered oscillation pattern was determined: within 24 hours two maxima of cab mRNA levels were detected. However, this entrained abnormal rhythm was not manifested at the molecular level and the circadian pattern reappeared under constant environmental conditions (e.g. darkness). This result favours the hypothesis that the oscillation pattern of the cab mRNA in tomato plants is not only endogenous but also hereditary.     

锌对番茄叶绿体亚显微结构的影响与光强度的关系(简报)

番茄植物缺锌时,茎尖停止生长,叶部和茎上出现褐色斑点,有明显的小叶病症状。此外,叶绿素含量减少,光合强度降低,叶绿体结构遭到破坏。陈保生和崔澂发现叶绿体含锌量显著降低,并提出缺锌阻碍了叶绿体的发育。Hoagland发现锌在植物中的生理作用与光有关,此后,不少人对植物需锌与光的关系进行了研究,证明植物在光下较暗中需锌较多。通过进一步研究,李佳格和崔澂证明锌对自养生长的绿色植物的作用与光有关,而对异养的非绿色植物的作用与光无关。Spencer还报道锌和光影响叶绿体希尔反应活性。由此看来,锌与叶绿体的结构和功能是密切相关的。但锌在     

Effect of Zinc on the Contents of Tomato Chloroplast DNA,RNA, Protein and Chl-Protein Complexes in Relation to Light

Changes of chloroplast DNA, RNA and protein contents in normal andzinc deficient tomato plants grown under different light intensity were studied in thispaper. It was shown that there is no much difference between normal and zinc deficient chloroplast DNA, RNA and protein e0ntents when the plants were grown underlower light intensity, while the DNA, RNA and protein contents of zinc deficient plantsdecreased dramatically under higher light intensity. The DNA and protein contentsof normal plants increased when light intensity was increased from 18000 lx to 45000 lx.The P700 Chl a-protein complexes and light harvesting Chl a/b-protein complexes of zincdeficient plants decreased seriously under higher light intensity.     

Diurnal Periodicity and Plaut Growth

The experiments were carried out to investigate whether other plant species, in addition to tomato plants, show injury symptoms when grown for 2 to 4 weeks in an aperiodic environment and to obtain information about physiological mechanisms involved in the response to the absence of environmental periodicity. The growth of seedlings of pea, peanut, and soybean, exposed to different daylengths at constant temperature, increased with Increasing length of the light period up to 16 to 20 hours, defending on the species. Further lengthening of the photoperiod did not result in significant increases in dry matter accumulated. The absence of environmental periodicity did not cause injury in these three species. Tomato plants responded in an entirety different manner. The optimal photoperiod for dry matter production by tomato plants was 18 hours and photoperiods longer than 20 hours caused interveinal chlorosis. Thus, tomato plants have an absolute requirement for a daily periodicity, white the other species do not in short-term experiments. Under conditions of constant temperature development of chlorosis by tomato plants may be prevented by a daily dark period of 4 hours or longer or by a daily period of drastically lowered tight intensity. Complete darkness is not essential, however. This suggests that development of chlorosis is not mediated through a photoperiodic response system. Involvement of a circadian oscillation may also be excluded. Aperiodic environmental conditions appear to affect the physiology of the tomato plant in a direct manner, possibly by influencing chlorophyll synthesis or degradation.     

Cytokinin autotrophy and differentiation in tissue cultures of haploid Nicotiana tabacum L.

Explants from the apical region (10 cm from the tip) of haploid Nicotiana tabacum cv. Wisconsin-38 were cultured on media with and without kinetin. Cell lines were selected in the dark and in the light. Cytokinins were extracted from the apical region of haploid plants and from callus tissues after 84 days of growth (third transfer culture). Chlorophyll was extracted from callus grown under light after 21 days of growth at each of the four cell line selection steps. Kinetin (+) cell lines and cytokinin autotrophic tissues grown in the light showed a compact growth pattern. Microscopic examination of these callus showed the presence of large numbers of nodules consisting of tracheary elements, parenchymatic cells, sieve elements and meristematic cells. Cytokinin-autotrophic callus grown in the dark showed an irregular growth pattern presenting regions of compact tissue and friable tissue. The compact tissue contained large amounts of nodules similar to those of kinetin (+) tissues and of cytokinin autotrophic tissues grown in the light. Extraction of the compact and the friable callus components showed high cytokinin activity in the compact region and low activity in the friable portion. It is suggested that cytokinin synthesis is related to the differentiation of the nodular structures. The amount of chlorophyll increased during the process of cytokinin autotrophic cell line selection.     

弱光胁迫对不同生育期番茄光合特性的影响

以耐弱光番茄品系02S02、02S32和不耐弱光番茄品系02S52、02S57为材料,以普通塑料大棚光照环境为对照(晴天9:00-11:00平均光强约为800 μmol·m^-2·s^-1),普通塑料大棚上覆盖一层黑色遮阳网模拟弱光环境(光强约为对照的50%),研究弱光对4个番茄品系苗期、开花座果期、果实膨大期光合特性的影响.结果表明：弱光环境下,4个番茄品系叶片光合速率在低光强下略有增加,超过此光强后大幅下降,不同品系在不同生育期的变化趋势一致,但变化幅度不同;叶片光补偿点和暗呼吸速率随发育进程逐渐降低,耐弱光品系的降幅均大于不耐弱光品系;叶片光饱和点、最大光合速率和表观量子效率在不同生育期均有所降低,但变化幅度不同,且与品系的弱光耐受性无一致性关系.     

Reinvestigation of the proposed red light effect on carotenogenesis in the fungus Verticillium agaricinum

The activities of glutamine synthetase (EC 6.3.1.2) and glutamate dehydrogenase (EC 1.4.1.2) appear to be inversely related in their distribution among the different tissues of 40-day-old tomato plants ( Lycopersicon esculentum L. cv. Hellfrucht Frühstamm), glutamine synthetase activity being highest in the leaves and glutamate dehydrogenase activity in the root. Leaf glutamine synthetase activity decreases with plant growth and shows diurnal variation with a maximum in the light and a minimum in the dark. In vitro, the activity of purified glutamine synthetase increases with the energy charge of the assay medium and decreases with increasing concentrations of p -chloromercuribenzoic acid. Glutamine synthetase activity in the plant may be regulated by physiological changes occurring during the light-dark transition periods.     

欧洲百合愈伤组织诱导及植株再生体系的建立

以欧洲百合(Lilium martagon)无菌苗鳞片为外植体, 探讨不同植物激素组合及光暗培养条件对愈伤组织诱导、增殖和再生不定芽的影响, 进而建立欧洲百合高效再生体系。结果显示, 诱导愈伤组织的最佳培养基为MS+0.2 mg?L^-1 TDZ+0.5 mg?L^-1 NAA, 诱导率为77.14%。在添加TDZ和NAA组合的培养基中进行继代培养, 愈伤组织极易褐化, 胚性活性下降; 采用添加6-BA和NAA组合的培养基可改善愈伤组织的褐化现象, MS+0.5 mg?L^-1 6-BA+0.1 mg?L^-1 NAA是愈伤组织增殖的最佳培养基, 增殖指数为2.93, 表明6-BA在愈伤组织状态维持中起关键作用。暗培养条件下愈伤组织的诱导率、增殖指数和芽再生系数最高, 分别可达77.14%、2.93和5.43, 且愈伤组织生长状态较好, 不定芽生根正常。研究建立的欧洲百合高效再生体系对于百合种质资源保存、基因工程育种及在国内的推广应用具有重要意义。     

Development of NaCl-tolerant line in Chrysanthemum morifolium Ramat. through shoot organogenesis of selected callus line

Plants were regenerated successfully through shoot organogenesis of a NaCl-selected callus line of Chrysanthemum morifolium Ramat. cv. Maghi Yellow (a salt sensitive cultivar), developed through stepwise increase in NaCl concentration (0-100mM) in the MS medium. The stepwise increase in NaCl concentration from a relatively low level to cytotoxic level was found to be a better way to isolate NaCl-tolerant callus line, since direct transfer of callus to high saline medium was detrimental to callus survival and growth. The selected callus line exhibited significant increase in superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2) activities compared to control callus (grown in medium devoid of NaCl). Stability of salt tolerance character of the selected callus line was checked by growing the calli in NaCl-free medium for 3 consecutive months followed by re-exposure to higher salinity stress (120mM NaCl). Among different growth regulator treatments, a combination of 5mgl(-1) TDZ (Thidiazuron) along with 0.25mgl(-1) NAA and 0.5mgl(-1) GA(3) was found to be the most effective for shoot organogenesis in selected callus line. The regeneration potential of the NaCl-tolerant callus ranged from 20.8% to 0% against 62.4% to 0% in control callus line. Under elevated stress condition (medium supplemented with 250mM NaCl), selected calli derived regenerants (S1 plants) exhibited significantly higher SOD and APX activities over both PC (positive control: control callus derived plants grown on MS medium devoid of NaCl) and NC (negative control: control callus derived plants subjected to 250mM NaCl stress) plants. In addition, the NC plants showed stunted growth, delayed root initiation, and had lesser number of roots as compared to S1 plants. Based on growth performance and antioxidant capacity, the S1 plants could be considered as NaCl-tolerant line showing all positive adaptive features towards the salinity stress. Further study on agronomic performance of these S1 plants under saline soil condition need to be undertaken to check the genetic stability of the induced salt-tolerance.     

Embryogenesis induction, callogenesis, and plant regeneration by in vitro culture of tomato isolated microspores and whole anthers

In this work, some of the different in vitro developmental pathways into which tomato microspores or microsporocytes can be deviated experimentally were explored. The two principal ones are direct embryogenesis from isolated microspores and callus formation from meiocyte-containing anthers. By means of light and electron microscopy, the process of early embryogenesis from isolated microspores and the disruption of normal meiotic development and change of developmental fate towards callus proliferation, morphogenesis, and plant regeneration have been shown. From microspores isolated at the vacuolate stage, embryos can be directly induced, thus avoiding non-androgenic products. In contrast, several different morphogenic events can be triggered in cultures of microsporocyte-containing anthers under adequate conditions, including indirect embryogenesis, adventitious organogenesis, and plant regeneration. Both callus and regenerated plants may be haploid, diploid, and mostly mixoploid. The results demonstrate that both gametophytic and sporophytic calli occur in cultured tomato anthers, and point to an in vitro-induced disturbance of cytokinesis and subsequent fusion of daughter nuclei as a putative cause for mixoploidy and genome doubling during both tetrad compartmentalization and callus proliferation. The potential implications of the different alternative pathways are discussed in the context of their application to the production of doubled-haploid plants in tomato, which is still very poorly developed.     

Trophic dependencies of some larval chironomidae (Diptera) and fish species in the River Thames

Experiments are described to characterise the heterotrophic potential of Westiellopsis prolifica Janet, which fixes nitrogen under light and dark conditions. The growth of the organism in terms of dry weight increase, was more in fructose, lactose, sucrose, sorbose, galactose, glucose, sodium acetate, mannitol, sorbitol, glycerol, ethyl alcohol and butyl alcohol, when the alga was pretreated with light and subsequently incubated with the substrates in light. Mannose, xylose, acetic acid, propionic acid, fructose 1,6 di Po₄, pyruvic acid, dihydroxyacetone and succinic acid decreased the growth of the organism in the same condition. In dark incubation after pretreatment with light, as well as in the dark, Westiellopsis showed a better growth response to almost all the exogenous substrates. However, after pretreatment either with light or dark, the test organism utilised exogenous substrates quicker in light than in dark incubations. These experiments would suggest that the substrate specificity and efficiency of substrate utilisation by the alga during its heterotrophic growth are governed by the growth conditions.