ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04618.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThe developmental cycle ofNostoc muscorum,a nitrogen‐fixing blue‐green alga, is controlled by the spectral quality of illumination. Red light with peak activity at 650 mμ induces development of filaments from a nonfilamentous (aseriate) stage of the life cycle. Red‐light photoinduction is reversed by simultaneous or subsequent exposure to light from a broad band in the green region of the spectrum. Photo‐reversibility of the red‐light induction, by green light, decays very slowly, remaining at an appreciable level for over 24 hr after the primary stimulus.Allophycocyanin is indicated to be the photoreceptor for red‐light induction. One or more phyco‐erythrins may operate as photoreceptors for reversal of induction.The dosage response and wavelength dependence of developmental photocontrol inNostoc muscorumA indicate that a nonphotosynthetic mechanism is involved in both developmental photoinduction and its p

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04585.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThree species of tropical oceanic phytoplankton were isolated from two locations in the eastern Pacific Ocean. Unialgal cultures were maintained in an enriched seawater medium. The effects of temperature, and, in separate experiments, illuminance, on the exponential cell division rates of those algae were investigated. For 2 isolates ofGymnocliniumsp. (probablyG. simplex),maximum growth rates were 1.25 and 1.7 divisions/24 hr, the optimum temperature range was 23‐29 C, the compensation illuminance was 35 ft‐c, and the saturation illuminance was 750 ft‐c and above. For a small species ofChaetoceros,the maximum growth rate was 6.0 divisions/24 hr, the optimum temperature range was 23‐37 C, the compensation illuminance was 10 ft‐c, and the saturation illuminance was 600 ft‐c. For a smallNannochlorisspecies, the maximum growth rate was 4.5 divisions/ 24 hr, the optimum temperature range was 27‐37 C, and the saturation illuminance was 800 ft‐c.Nannochlorisgrew heterotrophically by apparently utilizing organic matter supplied

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04586.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYGrowth in defined media of 32 populations ofGonium pectoralewas studied to learn more about the sexual isolation reported for this species. The 23 populations containing both mating types (+&‐) icere also studied for the ability to form zygotes in defined media. A preliminary study showed that some populations grew and reproduced sexually in a defined mineral medium, whereas others appeared to require exogenous organic materials for growth and/or zygote formation. The diverse reactions exhibited by the populations indicate physiological races which may explain, in part, the occurrence of sexual isolatio

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04587.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThree pelagic marine phytoplankters,Coccolithus huxleyi, Skeletonema costatum,andThalassiosira ro‐tula,and a facultative heterotroph,Cyclotella cryp‐tica,have been exposed to three organic substrates,viz,glucose, acetate, and glutamate, at low concentrations (organic carbon 0.25 mg/liter). Experiments were performed in the dark and light and the net assimilation of substrate was measured by using radiocarbon. The dark uptake of carbon dioxide was also determined, together with photosynthesis at near optimum light intensity. The expected heterotrophy was detected withCyclotella cryptica. Thalassiosira rotulawas found to assimilate glutamate at an appreciable rate. In all cases, however, the short‐term uptake of carbon dioxide in the dark was the greatest assimilation rate measured. Values are discussed in relation to their ecological significance and it is concluded that heterotrophic survival of these and probably most other algae in the open ocean xuould be impossible unless they were in contact with a high concentration of substrate in the form of particulate m

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04588.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYAn extractive procedure for detection of surplus‐stored phosphorus (luxury consumption) in algae and an enzymatic analysis for conditions of P‐limited growth in algae have been evaluated. A simple 60‐min boiling water extraction of algae known to contain surplus P separates essential P compounds and surplus‐stored P compounds. Surplus P compounds can be measured in the extract as orthophosphate. Extracts of algae limited in their growth by the amount of available P contain little or no orthophosphate. Limitation of algal growth by P supply induces the enzyme alkaline phosphatase. The activity of this enzyme can be measured at pH 9 using p‐nitro‐phenylphosphate as substrate. Algae which were P‐limited and contained no extractable orthophosphate have as much as 25 times more alkaline phosphatase activity than algae with surplu

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04589.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThe major C14‐labeled substance in sieve tube exudate ofM. pyriferaisD‐mannitol, comprising 3.6% (w/v). No sugars are detectable. Certain amino acids also possess some C14‐labeling and occur in significantly high concentrations in exudate. The exudate contains negligible ether‐soluble lipid, but has a large amount of protein and a high concentration of K+Neither protein nor lipid become labeled significantly in sieve tubes during short‐term translocation experiments with C14. In general the chemical composition of the assimilate stream is comparable to that of vascular plants and does not, consequently, necessitate a different mechanism for tran

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04590.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThe populations ofAsterionella formosaHass. in two subalpine lakes in the Rawah Wild Area, Colorado, were composed of colonies of five distinct size classes based on frustule length. The spring bloom in these two lakes was dominated by cells of the Beta or Gamma population, whereas the fall pulse was dominated by cells of the Alpha and Beta, or Alpha populations. The Beta population was physiologically unique in that it was parasitized by the chytridRhizophidium planktonicumCanter. The development of the parasite population could not be correlated with the concentration or the growth phase of the host population. The occurrrence of parasitism did not noticeiceably affect the population growth patterns of the Asterionella populations.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04591.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYA small, loose lying, unbranched, filamentous alga from the Ross Sea, Antarctica, is described as a new species,Lola irregularis.The genusLolais closely related to the generaHormiscia, Rhizoclonium,andChaetomorphain the family Cladophoraceae. A key to all known species ofLolais included. This is the first record of a species ofLolasouth of the Antarctic convergence.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1966.tb04592.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY