摘要:

Auxin treatment results in hyponastic curvature of the primary leaves ofPhaseolus vulgarisL. var pinto. Ethylene production by hyponastic leaves is detected within 1 hr after treatment with IAA in concentrations at or above 1μm. The amount of ethylene detected is proportional to the concentration of auxin applied. Untreated control leaves and leaves treated with 2,3,5‐tri‐iodobenzoic acid or gibberellic acid did not produce ethylene detectable by our equipment. The hyponastic curvature induced by auxin treatment can be inhibited by exogenous application of ethylene or ethylene‐generating compounds, and these treatments produce epinasty in auxin‐treated leaves. Treatment with inhibitors of ethylene synthesis or action, such as aminoethoxy‐vinylglycine, carbon dioxide, or heat treatment, prolong hyponasty. The planar form, therefore, appears to be affected by both hyponastic auxin effect and an epinastic ethylene effect.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12406.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

A new genus and species of Fagaceae are established for compressed leaves and attached fruits which represent one of the dominant taxa in the rich Miocene Clarkia flora of northern Idaho. The leaf and fruit morphology, cuticular and pericarp anatomy, and leaf phytoliths fall within the range of variation of the subfamily Fagoideae. The unique fruit consists of a large, exposed, distinctly keeled, trigonous nut and a diminutive basal cupule. The cupule has an apical frill of free, petiolate, leaflike appendages but lacks other ornamentation, and there is no evidence of a distinct Valvation. As no other genus of the Fagaceae has fruits with this combination of characters, a new genus is established and is referred to the subfamily Fagoideae. The Miocene genus seems most closely related to the extant genusFagus.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12407.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

AFagus‐like leaf fossil (cuticular compression) with an attached fruit, differing from any knownFagusspecies (fossil or extant) or other fagoid taxa, has been discovered from the Miocene Clarkia Lake deposits of northern Idaho. Because of its unusual morphology (especially the fruit) the fossil taxon has been described as a new genus and species,Pseudofagus idahoensisSmiley and Huggins. The successful previous use of paleobiochemistry in studies of fossil taxa from the Miocene Succor Creek Flora of Oregon suggested that chemical data might help clarify the taxonomic affinities ofPseudofagus.Indeed, examination of the chemistry of the fossil,Pseudofagus idahoensis, and comparison with extantFagusspecies and related fagoid genera indicate that: 1) based on steroid chemistry,Pseudofagus idahonesisdoes belong in the Fagaceae; 2) like all extant species ofFagus, the fossil lacks the tannin component, ellagic acid, which separates it from other extant fagoid genera, and 3) its simple flavonoid pigment profile places it closest to the extant North AmericanFagus grandifoliaor the European/EurasianFagus sylvatica.However, the exclusive presence of an isorhamnetin (3'‐methoxyquercetin) 3‐0‐glycoside, onocerane, and 5α‐cholestane imparts a species‐specific chemical character toPseudofagus idahoensis, which also sets it apart from extant species ofFagus.While the chemistry does not decide the taxonomic level to be accorded to the fossil, it certainly supports, along with morphology and anatomy, the distinctness ofPseudofagusand its proposed relationships within the Fagaceae.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12408.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

The arrangement of cellulosic fibrils in the cell walls of cotton fibers is very unusual; rather than exhibiting a continuous spiraling in one direction, they intermittantly reverse their gyre. Microtubules that line the periphery of the protoplasm, subjacent to the plasmalemma, tend to parallel the deployment of the cell wall microfibrils. It was not known whether this parallelism persisted through the reversal. By studying tangential sections of the cell wall/protoplasmic interfaces at the reversals, we show that congruity continues even through the reversals.Colchicine treatment did not appear to inhibit cellulose synthesis but it did abolish microtubules in the cotton fiber cells and deranged normal cell wall microfibrillar orientation. Previously, cotton fibers have been shown to possess most of the familiar organelles, but we found two new features not reported heretofore. They are microfilaments and peculiar “polygonal structures” that appear to be associated with the plasma membrane.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12409.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

Three types of cambial activity, two hitherto unreported, are described forStylidium.The four species of sect. Rhynchangium of subgenusNitrangiumhave woody cylinders in upright stems. In these a cambium formed beneath the endodermis produces a determinate quantity of fibers, vessel elements, and interxylary phloem strands toward the inside but no derivatives toward the outside; this was correctly reported by Van Tieghem and Morot (1884a) but doubted by subsequent workers. The same species have lignotubers in which a cambium produces contorted xylem (mostly vessels) to the inside, phellem toward the outside. InS. glandulosumandS. laricifoliuma cambium formed beneath the endodermis produces an indeterminate quantity of xylem (fibers and vessel elements) and interxylary phloem toward the inside, nothing toward the outside. The xylem is rayless and lacks axial xylem parenchyma. These three modes of cambial activity represent innovations within Stylidiaceae. The family has a wholly herbaceous ancestry if one can judge from the total lack of cambial activity in vascular bundles.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12410.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

The formation of a cavity between the rib meristem and the pith in winter buds ofPinus banksianais described. Necrosis of cells at the juncture of the rib meristem and pith begins in November, and by mid‐March the necrotic region enlarges, forming a cavity that separates the rib meristem from the pith. The cavity appears to be formed by autolysis, rather than a pulling apart of the cells. The function of the cavity remains speculative.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12411.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

The spatial patterning of and competition between established large‐toothed aspen (Populus grandidentata) and invading white pine (Pinus strobus) were examined in a 65‐yr‐old forest system at the AuSable Trails Institute of Environmental Studies, Kalkaska County, Michigan. Density, diameter, and distance measures were recorded for tree species on two 40 × 40 m grids containing 64 quadrats each 5 × 5 m. Several indices of dispersion were used to assess pattern and regression analysis of nearest neighbor distance to tree diameter provided an index of competition. The results indicate strong aggregation for both aspen and pine on a large scale, but regularity of pattern for pines in relation to their nearest neighbor. This regularity appears to be due to competition with established aspens and suggests that the spatial patterning of the aspens acts to control the spacing and subsequent development of the invading white pines.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12412.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

The effects of day/night temperatures and photoperiod on the growth and dormancy of paper birch (Betula papyrifera) were studied in seedlings from different geographic origins. The response of Alaskan plants to temperature and photoperiod was distinctly different from other seed sources. Alaskan plants required very long days to prevent cessation of growth while plants from southern seed sources grew on photoperiods as short as 14 hr. Low night temperature (14 C) antagonized the promotive action of long photoperiods in Alaskan plants but had little effect in other seed sources. High day temperatures offset the inhibitory effect of the cool night to a lesser degree in Alaskan plants than in plants from other locations. Dormancy induced by short photoperiods was antagonized (relieved ?) to a lesser degree by high night temperatures in Alaskan birch than in other seed sources.Betula papyriferavar.humilisfrom Alaska may be an incipient species since its morphological traits are accompanied by adaptive physiological responses to its environment. These responses are as distinct as its morphological characteristics.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12413.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

The pattern of biomass allocation of males and females and the sex ratio and growth characteristics of plants from three seed‐size classes inSilene albawere investigated in a greenhouse study. Seed size significantly affected adult plant size and flower production of both male and female plants, but there was no significant difference in the proportion of males and females emerging in three seed‐size categories. Male and female plants differed in the proportion of total biomass allocated to vegetative and reproductive structures and these differences were consistent across all seed‐size categories. Males allocated a greater proportion of their biomass to flowers than did females. Female reproductive effort was dependent upon the percentage of flowers producing mature capsules. Only females with greater than 20% fruit set have a higher reproductive expenditure than males. Consequently, female expenditure is potentially greater than males, but is spread out over a longer portion of the growing season. This difference in the timing of reproductive expenditures by males and females allows females to allocate more biomass to growth during the early flowering period and may therefore account for the common pattern in herbaceous perennial dioecious species in which adult females are larger than adult males.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12414.x

出版商:Wiley    

年代:1981

数据来源: WILEY

摘要:

The most mature spores available in herbarium specimens of the dicksoniaceous generaCystodium, Thyrsopteris, andCulcitawere studied by scanning electron microscopy and light microscopy, and representative specimens were analyzed to determine the number of spores produced per sporangium.ThyrsopterisandCulcitafeature 64‐spored sporangia, butCystodiumis consistently 32‐spored. Spores were analyzed both in their native state as found on the specimens and in a perine‐free state achieved by treatment with sodium hydroxide or acetolysis mixture. The sodium hydroxide assay demonstrated the presence of a perine inCystodium, Thyrsopteris, andCulcitasubgenusCulcita, but no evidence of a perine so defined was found inCulcitasubgenusCalochlaena.Spores ofCystodiumfeature a nearly psilate exine overlain by a striate inner perine and a granular outer perine and are in several respects similar to those ofMetaxyain the cyatheoid‐dicksonioid complex and to those ofSaccolomain the dennstaedtioids. The most matureThyrsopterisspores available may not have been fully mature. They feature a sparsely distributed, granular perinous layer over a microverrucate sculptine. The latter topography is taken as largely perinous since treatment with sodium hydroxide left a nearly psilate exine. The spore morphologies ofCystodiumandThyrsopterisreinforce the taxonomic distinctness of these monotypic genera indicated by their other characters. The two subgenera ofCulcitaare very dissimilar in their spore morphologies. The exine in subgenusCulcitaranges from psilate to slightly microverrucate proximally and distally, with varying margo development. Spores of subgenusCalochlaenaare strongly differentiated from those of subgenusCulcitaby their exine of broad spinules which vary in their degree of lateral fusion to each other and in the granular appearance of their distal surfaces. Spore morphology inCulcitastrongly supports the argument of those who would raise its subgenera to generic rank.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1981.tb12415.x

出版商:Wiley    

年代:1981

数据来源: WILEY