火炬松成熟合子胚培养直接器官发生和植株再生

基因型Ｈｂ,Ｍａ和Ｍｃ的火炬松成熟合子胚在附加１．０ｍｇ／ＬＮＡＡ,４．０ｍｇ／ＬＢＡ,５００ｍｇ／ＬＬＨ和５００ｍｇ／Ｌ谷氨酰胺的ＴＥ培养基上培养１２周后,在子叶和胚轴部位形成不定芽原基。然后将合子胚转移到附加０．５ｍｇ／／ＬＮＡＡ,０．０５ｍｇ／ＬＩＢＡ,２ｍｇ／ＬＢＡ,５００ｍｇ／ＬＬＨ和５００ｍｇ／Ｌ谷氨酰胺的ＴＥ不定芽分化培养基上,６周后分化产生大量不定芽,３种基因型中,Ｈｂ的直接不定芽     

火炬松(Pinus taeda L.)合子胚愈伤组织的器官发生和植株再生

以火炬松(Pinus taeda L.)的成熟合子胚为外植体在附加NAA和BA的TE培养基上诱导产生了淡黄色、疏松、有光泽的颗粒状愈伤组织。经过愈伤组织的保持和增殖培养及不定芽原基的诱导培养后,进行了不同激素、低温处理和蔗糖浓度对不定芽分化的影响实验。结果表明,在附加0.5 mg·L~(-1)IBA和2 mg·L~(-1)BA的TE培养基上,愈伤组织上的不定芽分化频率最高达62.15%。不定芽分化的最佳低温处理时间是5—6周,最佳蔗糖浓度是25—30 g·L~(-1)。不定芽经伸长培养后取高于1cm的小苗用于生根。在附加IBA、BA和GA_3的TE培养基上不定芽的生很频率最高达46%。     

THE FINE STRUCTURE OF THE GUARD CELLS OF HELIANTHUS ANNUUS

The guard cells of Helianthus annuus contain elements of endoplasmic reticulum and large numbers of mitochondria and dictyosomes. Each guard cell possesses a complex system of small to large vacuoles which contain small, membrane-bound vesicles; the vacuole may actually be one highly invaginated and dissected vacuole extending throughout the cell. A highly developed grana fretwork within the plastids implies full photosynthetic capability and the capability of producing the osmoticulum required for turgor change. No plasmodesmata occur between the sister guard cells or between the guard and epidermal cells. It is postulated that there is a close relationship between plastid development and the presence or absence of plasmodesmata. No microbodies were positively identified in any of the guard cells. Microtubules appear to lie in two planes, thereby giving support to the “two system” observation for microtubules in the guard cells of Pisum sativum.     

WHOLE-EMBRYO CULTURE AND THE STUDY OF MAMMALIAN EMBRYOS DURING ORGANOGENESIS

1. Simple and reliable methods are now available for growing rat and mouse embryos in culture at all stages of organogenesis. Primitive-streak embryos can be maintained for up to 5 days in culture while they develop to early foetal stages. Older embryos are maintained for progressively shorter periods and the most advanced stage that can be supported is equivalent to the rat foetus of 15 days' gestation. 2. The rates of protein synthesis and differentiation of the younger embryos in vitro are similar, and of head-fold embryos identical, to those in vivo. After the formation of the limb buds growth is slower, with protein synthesis more retarded than differentiation, resulting in embryos or foetuses that are well formed but smaller than in vivo. This slowing of growth of the older embryos in culture is probably caused by the lack of a functional allantoic placenta. 3. The embryos of some other species, including the guinea-pig, hamster, rabbit and opossum have also been maintained in culture during organogenesis but the results are not yet as good as those for rats and mice. 4. Maximum growth of rat embryos explanted with the visceral yolk sac intact is obtained in undiluted homologous serum, though adequate growth for many studies can be maintained in mixtures of serum with chemically defined tissue-culture media. The best results are obtained in serum prepared from blood centrifuged before clotting has occurred (I.C. serum) and heat-inactivated. The importance of a high concentration of serum in the culture medium may be related to the mechanisms for uptake, transport and digestion of macromolecules by the rodent yolk sac. 5. There is no convincing evidence for a changing rate of oxygen consumption during organogenesis but there is strong evidence for changes in energy metabolism. At the beginning of organogenesis, the embryo shows a high rate of anaerobic glycolysis and of pentose-shunt activity. During the following days these decline while activity of the Krebs' cycle and electron-transport system increases. Anoxia, or exposure of the embryo to carbon monoxide, increases glycolysis and reduces growth rate. 6. The earliest stages of the formation of the heart and blood circulation can be closely observed in culture. The heart rate of the 111/2-day rat embryo is about 160 beats per minute at 38°C, and falls by about 7% per degree for lower temperatures. Several drugs that are cardioactive in the adult also affect the frequency of the heartbeat in the embryo, and the pattern of response suggests that the adrenergic receptors in the embryo develop before the cholinergic receptors. Experiments in which embryo and yolk sac were cultured separately, as well as together, have indicated that haemopoiesis can occur in the embryo only after a migration of stem cells from the yolk sac. 7. Microsurgery has been successfully applied to embryos in culture in studies on morphogenetic movements, heart development, axial rotation, limb-bud regeneration and placenta formation. Biochemical studies of normal morphogenesis have been few, but one has shown a high rate of hyaluronate synthesis by the embryo which may be related to the maintenance and expansion of extracellular spaces and the formation of the neural folds. 8. Embryos are particularly sensitive to teratogenic agents during organogenesis. Teratogens that have been studied on whole embryos in culture include trypan blue, antisera, hyperthermia, anaesthetics, and abnormal concentrations of vitamins, oxygen and glucose. Many of the malformations induced have been similar to those obtained after administration of the same agents in vivo and have demonstrated a direct teratogenic effect on the embryo independent of the maternal metabolism. It is suggested that culture methods may provide a valuable additional screening procedure for new drugs and other potentially embryopathic agents.     

马尾松成熟合子胚的体细胞胚胎发生和植株再生

采用马尾松（Ｐｉｎｕｓｍ ａｓｓｏｎｉａｎａ Ｌａｍ ｂ．）成熟合子胚为起始外植体,在含２,４－Ｄ １０ ｍ ｇ／Ｌ,ＫＴ和ＢＡ 各４ ｍ ｇ／Ｌ的ＤＣＲ培养基上得到胚发生培养物。将白色半透明的愈伤组织（含早期原胚）在含２,４－Ｄ１．０ ｍ ｇ／Ｌ,ＫＴ和ＢＡ 各０．４ ｍ ｇ／Ｌ的ＤＣＲ培养基上保持并增殖。在附加９０００ ｍ ｇ／Ｌ肌醇的ＤＣＲ高渗培养基上得到粗壮的后期原胚。ＡＢＡ 和活性炭同时使用能促进子叶胚的形成,最高频率为３５．１％ 。在无激素培养基上,成熟体细胞胚萌发并进一步形成完整小植株     

向日葵Ti T—DNA转化系的原生质体培养和细胞培养

根癌农杆菌离体感染向日葵子叶、下胚轴外植体形成的Ti T-DNA转化组织在激素条件下长期继代培养后,用来进行原生质体培养和细胞培养。适于B6S3转化系和T37转化系原生质体培养的培养基分别为附加不同激素和糖类的C81V和DPD培养基。用液体浅层法培养3～5天时,原生质体开始分裂。10天后形成细胞团。B6S3转化系还可直接从原生质体产生原胚状结构。转化系的细胞克隆均保持着激素自主型生长特性和冠瘿碱合成酶合成特性。     

GENETIC HISTORY AND GENERAL COMPARISONS OF TWO ALBINO MUTATIONS OF HELIANTHUS ANNUUS

Wallace , Raymond H. (U. Connecticut, Storrs.), and Helen M. Habermann . Genetic history and general comparisons of two albino mutations of Helianthus annuus. Amer. Jour. Bot. 46(3) : 157-162. Illus. 1959.—The genetic history of the progeny of a single ultrasonically-treated seedling of Helianthus annuus L. has been summarized for the 6 generations for which quantitative data are available. A yellow mutation was found in the F₂ generation and later in the F₅, a second, white mutation occurred. Both mutants have been grown to maturity by grafting them onto normal green host plants and they have set viable seeds. Both pigment-deficient conditions are inherited as single recessive factors. These albino strains form chlorophyll during their seedling stages if they are grown at low light intensities. Chlorophyll is destroyed, however, under bright illumination and, once bleached, the capacity for chlorophyll formation appears to be lost. The yellow mutant contains xanthophyll but no traces of carotene have been found. In the white mutant, neither carotene nor xanthophyll have been detected. Flower color in the yellow mutant is normal while the flowers of the white mutant have no apparent pigmentation. The growth pattern of grafted yellow mutants is normal, save for a stiffer and woodier condition and a greater resistance to wilting. These characteristics have also been observed in grafted white mutants. In addition, there is a pronounced reduction in leaf size in the white mutant.     

根癌农杆菌T-DNA在向日葵离体组织中的转移与表达

利用根癌农杆菌B6S3和T37菌株离体感染向日葵切伤的子叶、下胚轴外植体。感染处理的外植体与菌共培养三天后,在无激素条件下以60—96％的频率获得了离体转化的瘤组织。瘤组织在继代培养过程中具有激素自主性生长特性。在无激素培养基上瘤组织的生长速率显著高于正常愈伤组织。所有随机取样测定的瘤组织内均有相应冠瘿碱的存在。     

CULTURE OF MATURE ECOTYLEDONOUS EMBRYOS OF PHASEOLUS VULGARIS AND THE NUTRITIONAL ROLE OF COTYLEDONS

Embryos of Phaseolus vulgaris L. were excised from seeds and cultured with cotyledons removed to determine the actions of various cultural conditions upon embryo development. Four media were tested, but ecotyledonized embryos did not grow as rapidly on any of them as did embryos with intact cotyledons on agar-water media. Comparisons of growth of ecotyledonized embryos with embryos bearing fractions of cotyledons indicated ecotyledonized embryos cultured on nutrient media grew about as well as embryos bearing cotyledons from which 97% of the volume had been removed surgically. The final weight of ecotyledonized embryos was greater when detached cotyledons were placed near them and was even greater when extracts of detached and incubated cotyledons were employed in the nutrient medium. Benzyladenine, kinetin, gibberellic acid, indole-acetic acid, presence of sucrose, and light or dark culture failed to enhance the ability of incubated cotyledons to stimulate growth of embryos.     

GROWTH OF EXCISED PINE EMBRYOS AND THE ROLE OF THE COTYLEDONS DURING GERMINATION IN VITRO

A study was made of the role of the cotyledons, embryo orientation, surgical treatment, darkness, light, and autoclaved coconut milk on the growth of Pinus lambertiana Dougl. embryos in vitro. The embryos did not require an haustorial function of the cotyledons in vitro. Removal of the shoot meristem drastically altered the developmental physiology of the embryo and the function of the root meristem was severly inhibited. Positional effects on embryo growth were reversed by darkness. In the light vertical-inverted tube cultures displayed better growth than horizontal-inverted tube cultures, whereas in the dark the horizontal-inverted tube cultures displayed better growth than the ver ical-inverted tube cultures. Autoclaved coconut milk had no statistically demonstrable effect on embryo growth as measun d by the analysis of variance and Student-Newman-Keul's range test; however, the graphical analysis suggests that, in conjunction with the presence of the shoot meristem, there may be a slight beneficial response to autoclaved coconut milk.     

INVESTIGATIONS ON AUXIN-GIBBERELLIN INTERACTION ON THE PHOTOTROPISM OF HELIANTHUS ANNUUS HYPOCOTYL

On applying IAA-GB and IAA-NAA mixtures to the hypocotyls ofHelianthus annuus, the plants showed an increase and a decrease,respectively, in their phototropic response compared with thecontrol treated with IAA-H₂O only. In the in vitro experimentsit was observed that the illumination (with 1,500 lux light,lasting for 24 hr) caused photoinactivation of IAA in the mixturesof IAA-H₂O, IAA-GB and IAA-NAA by 50%, 24% and 0%, respectively.In the presence of 0.01% riboflavin as a photosensitizer inthe same mixtures, the degree of photodestruction of IAA causedby the same illumination was 92%, 97% and 86%, respectively. The stronger positive phototropism in the IAA-GB treated hypocotylwas accounted for by the situation that on the illuminated sidethe photo-inactivation of IAA was accelerated by GB, while onthe shaded side IAA and GB acted synergistically. On the otherhand, the weaker phototropism in the IAA-NAA treated hypocotylwas explained as due to a partial inhibition of photoinactivationof IAA by NAA. (Received October 6, 1962; )     

THE VASCULAR TRANSITION REGION OF HELIANTHUS ANNUUS. I. BILATERAL AND UNILATERAL PATTERNS OF DIFFERENTIATION

The vascular transition region of Helianthus annuus L. may exhibit either a unilateral or a bilateral differentiation of primary phloem groups. The unilateral type of transition has been previously described but the bilateral type with its two variations is described here for the first time. The three patterns of transition are compared, and the significance of the variability of transition regions is discussed in terms of basic transition types and phylogenetic importance.     

VARIATION AND LOCALIZATION OF FLAVONOID AGLYCONES IN HELIANTHUS ANNUUS (COMPOSITAE)

Flavonoid aglycone variation within Helianthus annuus, a species widely distributed throughout North America, was analyzed. Flavonoid aglycones of H. annuus consist of two types, flavones and chalcones. The flavone aglycones are sequestered in glandular trichomes that occur on both leaf surfaces, whereas the chalcone aglycones appear to be incorporated in the waxy leaf cuticle. Considerable variation in flavonoid profile was observed with some plants exhibiting as few as one, and others as many as seven of the eight aglycones detected. No definable phytogeographic patterns were observed for this flavonoid variation. Flavonoid aglycone variation also did not differentiate the infraspecific taxa within H. annuus.     

白杄体细胞胚胎发生及其植株再生

白杄(Picea meyeri Rehd.et Wils.)的成熟胚在4～6℃低温下保存1个月后,接种于改良LP 2mg/L 2,4-D 1mg/L 6-BA的培养基上,黑暗条件下培养1个月便可产生白色半透明的胚性愈伤组织。整体染色封片观察表明,胚性愈伤组织由很多很长的胚柄细胞及其顶端的胚细胞团组成,这种愈伤组织培养物称为胚性胚柄团。胚性胚柄团在MS 1mg/L 2,4-D 1mg/L KT的继代培养基上黑暗条件下可保持旺盛的增殖能力和分化潜力。当胚性胚柄团转到MS 5mg/L ABA 5mg/L AgNO_3的分化培养基上,1个月后可产生大量正常的体细胞胚。体细胞胚成熟以后转到含0.5％活性炭的无激素1/2MS基本培养基上约40d后可长出1.5～2.5cm的根,约60d后可长出真叶。光、ABA、蔗糖及AgNO_3浓度是影响体细胞胚发生的主要因素。     

SHOOT TIP CULTURE OF HELIANTHUS ANNUUS—FLOWERING AND DEVELOPMENT OF ADVENTITIOUS AND MULTIPLE SHOOTS

Shoot multiplication of Helianthus annuus was optimal from half shoot apices cultured on MS media with 0.1–1.0 mg/1 benzyl adenine or kinetin. Auxins inhibited multiplication and promoted callusing. Rooting was poor and was not promoted by auxins. Flowering of multiple shoots was observed after as little as 3 wk of culture. A number of plant growth regulators and environmental conditions had no effect on flowering which supports the determinate apex theory for sunflower (Habermann and Sekulow, 1972). Adventitious shoots were induced on leaves of the multiple shoots in some inbreds.