摘要:

Excised tissues of dark‐grown seedlings representing long day, short day and daylength indifferent photoperiodic classes were assayed for nonphotochemical changes in phytochrome. In all tissues tested, these changes were qualitatively the same. A brief irradiation with red light was followed in darkness by a decrease in total phytochrome, the disappearance of PFR, and an increase in detectable PR.Within the limits of the tissues tested, the kinetics of phytochrome change can be assigned to three groups on the basis of rates. These groups are represented by coleoptiles, hypocotyls and epicotyls, and mesocotyls. The kinetics could not be distinguished on the basis of the photoperiodic class of the mature plant. The significance of these kinetics with respect to the photochemistry of phytochrome conversion is discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06804.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Fructification in cultures ofCyathus stercoreus(Schw.) de Toni is a process in which photochemical reactions are involved. The amount of light energy required for fruiting to take place is a constant. This photoinductive constant is approximately 17200 foot‐candle‐hours considering optimum temperature (25 C) and light‐saturation effect with reference to light intensity (240 ft‐c). It is hypothesized that photoinduction becomes operative when a hypothetical “photoreceptive precursor” develops in the mycelium. The development of such a precursor is believed to occur when conditions unfavorable for good vegetative growth (e.g. shortage of food supply) develop in the culture. Internal metabolic pathways then shift to favor the production of the photoreceptive precursor. A linear function is derived which characterizes the biological photoinduction of fruit‐body formation.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06805.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Mass movement is a form of streaming in which distinct quantities of cytoplasm flow as entities along a transvacuolar strand or cytoplasmic striations of the peripheral cytoplasm. An individual mass can move at variable velocities during a brief period of time or change its direction of flow. Two masses, when moving at different velocities in the same or different directions along a strand, can be observed to collide. This can occur repeatedly, resulting in the formation of a mass of considerable size. Many organelles can be observed to move at velocities differing from that of the mass; some can be observed to change directions during their movement. A mass may represent a dilation of one or more microstreams within the cytoplasm. Folding of the microstreams within a mass may explain the changes in the direction of movement observed for some organelles. Several levels of movement are associated with streaming, including those of the ground plasm, of the organelles, of the transvacuolar strands and of the cytoplasm masses. These, and possibly more subtle aspects of the streaming phenomenon, must be incorporated into any theory of streaming.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06806.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

New procedures of aseptic bryophyte culture which permitted the alteration of the culture medium during the life cycle were used to investigate development and gemma differentiation inScapania nemorosafrom the aspect of organic nutrition. Cultures started from gemmae (asexual reproductive structures) were treated withl‐arginine,l‐histidine andl‐glutamic acid upon reaching each of 3 developmental stages: Cell Mass stage, Juvenile stage, and Early Adult stage. Ten weeks after each treatment, quantitative determinations of growth and gemma formation, as well as a qualitative appraisal of the effect of treatment on development, were made on representative cultures. In addition, an amino acid analysis was made of young plants which had not produced gemmae, of older plants which had produced gemmae, and of gemmae. The results of the culture experiments indicate that all 3 amino acids are stimulatory to production of gemmae and that the degree to which this is so is contingent on the ontogenetic stage treated. Moreover, the qualitative data, in conjunction with the amino acid analysis, indicate that each compound influences gemma formation in a somewhat different manner.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06807.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

In vascular plants, the apical meristem of the shoot normally represents a continuation of growth in the apical meristem of the embryo itself. This is not the case inArceuthobium.Here the shoot apex of the embryo is rudimentary and eventually dies after infection of the host occurs. The inflorescence ofArceuthobiumis, therefore, an adventitious structure originating in the endophytic system rather than from the shoot apex of the seedling. Inflorescence buds arise in either of 2 ways. In some species (A.douglasiiandA. americanum), buds first appear as small meristematic protuberances on the outer surface of cortical strands. In other species (A. campylopodum), the buds arise at the ends of short branches. The former, or diffuse, type gives rise to inflorescences along the entire surface of the host branch; in the latter, or condensed, type inflorescences are formed in clusters. Early ontogeny of the inflorescence apex of both types is described. Studies of subsequent growth of the inflorescence apex show 5 well‐defined plastochronic stages: (1) maximal area stage; (2) minimal area stage; (3) early post‐minimal stage; (4) late post‐minimal stage; and (5) pre‐maximal stage.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06808.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Cultures ofChlamydomonas eugametos, Chl.sp.,Carteria eugametos, C. crucifera, C. radiosa, andC.sp. were examined with the electron microscope to determine generic differences betweenCarteriaandChlamydomonasat the ultrastructural level. The ultrastructure of the flagella, mitochondria, dictyosomes, nuclei and ground substance was noted to be similar in all species. The cellular boundary of all species exceptChlamydomonas eugametoscontains a 250 A intermediate layer of unknown chemical composition between the fibrillar cellulose wall and the outer capsule layer. Four structural features other than the number of flagella distinguishCarteriafromChlamydomonas:the intermediate layer of the cellular boundary, the chloroplast, the pyrenoid and the eyespot. Only in theCarteriaspecies is the intermediate layer traversed by striations or 12‐mμ‐wide bars. Striations in the cellulose wall surrounding the flagellar channels also appear inCarteria eugametosandC. crucifera.The chloroplast lamellae of theCarteriaspecies are grouped into discrete stacks of invaginated thylakoids termed pseudograna. The chloroplast lamellae ofChlamydomonasare broad and sheet‐like and are also invaginated although less frequently than are the pseudograna ofCarteria.The phenomenon of infolding of the chloroplast lamellae is suggested as a general developmental process in the formation of new thylakoids. InCarteria, single thylakoids traverse the pyrenoid and there are 2 rows of granules in the eyespot. Favorable micrographs of the eyespot indicate that the granules may be osmiophilic granules of the chloroplast chemically modified for a photoreceptive function.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06809.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Attraction of male gametes ofAllomycesto sirenin concentrations as low as 10−‐10m has been demonstrated. Increasingly strong responses are observed to concentrations up to 10−‐6m. The response is slightly weaker at 10−‐5m and very weak at 10−‐4m. Microscopic studies suggest that the attraction comes into the category of tropotaxis, a direct approach to a sirenin source occurring. Male gametes have been shown to inactivate sirenin. The possibility that this inactivation is an adaptation process enabling the gametes to maintain sirenin sensitivity over a 100,000‐fold concentration range is discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06810.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The response of the various motile phases ofAllomycesto sirenin and to casein hydrolysate was examined. Male gametes respond chemotactically to sirenin but not to casein hydrolysate. Female gametes do not respond to either of the reagents. Zygotes, mitospores and meiospores respond to casein hydrolysate but not to sirenin. The zygotes were shown to respond to the individual amino acids cysteine, proline and serine but not to the other amino acids tested. Chemotropism of germ‐tubes to casein hydrolysate was also demonstrated. The high activity of sirenin and the specificity of its action is in marked contrast to the low activity and lack of specificity of the amino acids in producing chemotactic and chemotropic responses.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06811.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The growth in terms of linear extension and dry weight, endogenous respiration, bioluminescence and ATP concentration ofCollybia velutipeshas been considered. After an initial lag phase of approximately 4 days, linear growth extension with time is obtained. Dry weight measurements, however, indicate that secondary activity in previously formed cells occurs. One such activity is the formation of glycogen. The presence of glycogen, as determined by electron microscopy and several chemical tests, has been established inC. velutipes.Optimal endogenous respiratory activity occurs in tissue less than 48 hr of age, while maximal bioluminescent activity occurs in tissue that is 2–6 days in age. The maximum ATP concentration occurs in tissue approximately 7 days old.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06812.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Light emission from the luminous fungusCollybia velutipeshas been studied under various nutritional conditions and in no instance has growth been obtained with the complete absence of light emission. The effect of varying pH, various nitrogen and carbon sources and the response to different vitamins has been considered. Ammonium‐nitrogen or aspartic acid, glucose and pH 6.0 were shown to be most effective for optimal light emission. This isolate requires the thiazole moiety of the thiamine molecule for light emission; the effects of the thiamine antagonists pyrithiamine and oxythiamine were also studied.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06813.x

出版商:Wiley    

年代:1965

数据来源: WILEY