摘要:

New reproductive material of fossil Salviniaceae from the Edmonton Formation is described. It establishes the existence ofSalviniain the Upper Cretaceous of North America. Taxonomic and morphologic evaluations of the Cretaceous species of Salviniaceae are presented and their evolutionary significance discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb09996.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

During development (expansion), the cotton leaf passes through a stage in which it is highly susceptible to ozone. This period of susceptibility occurs after the maximum expansion rate but before complete expansion occurs. The period of maximum susceptibility corresponds to a minimum concentration of soluble sugars and free pool amino acids. Specific amino acids such as aspartate, serine, threonine, glutamate, asparagine, alanine, glycine, valine, isoleucine, leucine, histidine, and tryptophan tended to reach a minimum concentration at about the same time leaves were susceptible to ozone. Ozone exposure during the susceptible period is manifested by visible leaf flecking of the upper surface and a dramatic (up to 2 fold) increase in total free pool amino acids. Most individual amino acids tended to increase except for phenylalanine, alanine, phosphoserine, phosphoethanolamine, and ethanolamine. Soluble protein is decreased but not to the same extent that the free pool amino acids increase. Because there is ample evidence that ozone enters the leaf during nonsusceptible periods as well as susceptible periods, it is postulated that ozone damage results because of the depletion of soluble reserves (carbohydrates and amino acids). Perhaps repair of damage cannot occur.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb09997.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Pollen of seven species inTetraplasandraand three species in related genera were studied with light and scanning electron microscopes. A new thin‐section technique was employed for the study of exine stratification and apertural structure. This study reveals several previously undescribed pollen structures for the group. Trends toward increase in pollen size and in specialization of other pollen characters are evident inTetraplasandra. Pollen ofReynoldsiaandPeekeliopanaxdiffers fromTetraplasandrain the pertectate sexine and the absence of inner nexinous breaks, respectively. A pollen correlation study shows thatMunroidendronfalls readily within the genusTetraplasandrabut is distinguishable from the latter by its bifurcate colpi.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb09998.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The dominant tomato mutant ‘Curl’ differs from normal plants in several striking respects including the following: misshapen laminar structures such as leaves, sepals, and petals; stunted petiole and rachis; and persistent growth of blade and stem tissue from the adaxial surface of the rachis. These tissues as well as others which appear morphologically normal show gross histological abnormalities. Also evident in sections of mutant tissue is the appearance of areas containing numerous crystalline inclusions and a lack of bodies showing a stainable starch reaction in palisade and mesophyll of leaves and in endodermis and pith cells of the stem.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb09999.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The taxonomically complex eastern U. S. speciesR. caroliniensisproduces six functional or partially functional floral morphs. They are chasmogenes, reduced chasmogenes, morphologic protogynous chasmogenes, multistylous chasmogenes, cleistogenes, and semi‐cleistogenes. The plants are uniformly self‐compatible and generally produce normal fruits and seeds. The species has the morphological basis of a nearly balanced breeding system between allogamous and autogamous reproduction. Observations and comparisons on garden and greenhouse cultures suggest thatR. caroliniensisis a seasonal cleistogamic species, and it is proposed that the different breeding systems are the chief causes of the difficult taxonomic problem in the species.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10000.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Trigger hairs ofDionaea muscipulafixed in glutaraldehyde and OsO4were prepared for study in the electron microscope. Electron micrographs of the active zone of the trigger hair reveal three regions in which the cells differ in size, shape, and cytoplasmic content. Each region contains large numbers of protein bodies and mitochondria with densely packed tubular cristae. Vacuole‐like structures containing protein bodies or an anastomosing system of cisternae, or occasionally both, are also present. Found only in the indentation cells is a complex, whorled endoplasmic reticulum. A concentric lamellar arrangement of the endoplasmic reticulum around the vacuolar structures is often observed. The lateral walls of the indentation cells are disproportionately thick while end walls are thin. The basal walls of these cells contain many plasmodesmata. Plasmodesmata in the anticlinal and podium cells pass through constricted zones in the cell wall and are particularly numerous in the peripheral podium cells. The possible functional significance of these structures is discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10001.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Leaf initiation rate, leaf primordium growth rates, and apical volume growth rates were determined for seedlings ofTriticum aestivumcv. Ramona 50 under controlled environmental conditions. Three leaf primordia are present in the caryopsis, and three more leaves are initiated within the first two weeks after germination with a mean plastochron length of 95.5 hr. Volume growth rates of the apical region were determined on six apices which had six primordia each. The mean radial expansion rate was 0.467/plastochron, and the vertical expansion rate was 0.457/plastochron. The volume expansion rate was 1.393/plastochron. The mean volume doubling time was 0.498 plastochrons or 47.1 hr.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10002.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The effects of three levels of relative humidity (40%, 65%, and 90%) and two types of containers (clay and plastic) on the seedling growth of three F1hybrid annuals were determined after 14 days of controlled‐environment treatment. Forty percent relative humidity was severely limiting to the seedling growth of ‘Blue Blazer’ ageratum(Ageratum houstonianumMill.), ‘Pink Cascade’ petunia(Petunia hybrida Vilm.), and ‘Double Eagle’ marigold(Tagetes erectaL.). Raising the relative humidity to 65% resulted in striking increases in fresh weight, dry weight, and leaf area, especially when clay containers were used. Height of the main shoot was increased significantly at 65% relative humidity but node number was influenced only slightly. Increasing the relative humidity further to 90% had no significant effect on fresh weight, dry weight, or percent dry weight for any of the three species, in either container. Leaf area was increased significantly at 90% only in ageratum seedlings grown in clay pots. Each species responded differently to the type of container used. The fresh weight and dry weight of petunia seedlings were significantly greater in plastic pots at every level of humidity while those of marigold seedlings were unaffected by the type of container used. Ageratum seedlings, on the other hand, had significantly greater fresh weights and dry weights in clay pots only at 90% relative humidity.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10003.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Volvariella volvacea(Bull. ex Fr.) Sing. is a large pileate edible fungus of the tropics and sub‐tropics. It has two kinds of spores, one being the sexual basidiospores in tetrads and the other the asexual chlamydospores. Both monosporous and vegetative hyphae are multinucleate, and there are no clamp connections. Fifty monospores were isolated from two fruiting bodies, and were cultivated individually with four replicates under controlled laboratory conditions. On the average, 76% of the monosporous progenies were fertile. The fungus is homothallic. The development and life cycle of the fungus are described. The possible mechanisms of homothallism are also discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10004.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The lichens,Nephroma expallidum(Nyl.) Nyl. andN. arcticum(L.) Torss., consistently have at least two symbionts in a single thallus: a green alga in the algal layer and a blue‐green alga in the internal cephalodia. The cephalodia originate from algal cells in contact with the lower surface of the lichen, in the zone of rhizine formation. The rhizines surround the epiphytic algal colony and form a second cortical layer; following dissociation of the original lower cortex, further growth of the two organisms results in the cyanophyte colony being enveloped by a compact layer of fungal tissue and positioned in the lichen medulla. The colony may eventually assume a superior or inferior position in relation to the lichen thallus, depending in part on the lichen species.Nephroma anticummay have two distinct morphological forms of blue‐green algae in the same thallus and occasionally in the same cephalodium. It appears that the relationship that exists between the cephalodial algae and the lichen thallus is antagonistic and results, in some cases, in the exclusion of the green algal layer and death to the cephalodial cyanophytes.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10005.x

出版商:Wiley    

年代:1971

数据来源: WILEY