摘要:

Detachment and incubation ofElodealeaves promoted callose synthesis in all cells, especially in epidermal pits and in sieve tubes. Phloem was detected in the midrib by fluorescent staining of callose induced to form on sieve plates. In EM views of mature sieve elements nucleus and tonoplast were lacking, mictoplasm replaced cytoplasm, mitochondria were fewer in number, and large plastids contained crystalline inclusion bodies. Slime was present as compact aggregates and as individual fibrils in mictoplasm and sieve pores. Deposition of callose is considered in relation to the blockage concept of callose function.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06954.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

ProsopisandAcaciafrom North and South America were studied in the laboratory under constant and increasing night length under two temperature regimes. TheProsopis juliflora(Sw.) DC. complex showed strong populational differentiation;Acacia farnesiana(L.) Willd. showed minimal populational differentiation. InProsopisa population from Oklahoma (36° N) showed the greatest inhibition of stem height under increasing night length. A population from Peru (6° S) showed least control of stem height by night length. InAcaciathe response of the latitudinal series was relatively uniform within each of the 6 sets of light period‐temperature conditions. In general the height increase forAcaciawas two to three times greater under the warmer regime than under the cooler regime at a given night length. SinceAcacia farnesianaoccurs sympatrically with theProsopis julifloracomplex over a broad range of latitudes, it is of interest to find that the distributional mechanisms of these two leguminous trees are basically different.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06955.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

Liquid‐grown callus was used to study the nutritional requirements for rooting of a triploid form of normally diploid quaking aspen (Populus tremuloidesMichx.). In modified Wolter's liquid medium, tan rough‐surfaced spheres of callus grew rapidly when supplied with a high concentration of 2,4‐D (0.5 mg/liter), but light‐yellow uniformly smooth and firm spheres grew more slowly with a low level of 2,4‐D (0.04 mg/liter) plus kinetin. When tissue was grown uncut in liquid for 1, 2, or 3 months, then subcultured to a low‐2,4‐D agar medium, rooting increased primarily with the age of the source tissue rather than the initial explant size. The surface of the youngest tissue source was almost smooth, but free columnar proliferations extended out from the surface for two or three cells in 2‐month‐old tissue and for three to six cells in the 3‐month‐old tissue. The relationship of increased rooting with increased surface cell‐proliferation of older tissue was not determined anatomically.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06956.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

Three species of fossil wood representing two genera are described. The specimens are from a collection of woods from the Upper Cretaceous Panoche formation of central California.Tetracentronites panochetrissp. nov. resembles angiosperm wood in ray structure and vascular pitting but lacks vessels.Plataninium platanoidessp. nov. is similar to the wood ofPlatanus,and the evidence presented points to a direct relationship. The resemblance betweenPlataninium cali‐fornicumsp. nov. and the woods of certain Icacinaceae is discussed, but evidence of relationship is inconclusive.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06957.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

A numerical taxonomic study of the angiosperm family Limnanthaceae is presented. The 21 OTUs include all taxa recognized in a recent monograph ofLimnanthes(Mason, 1952), plusFloerkea proserpinacoides,two undescribedLimnanthesspecies, and two artificial interspecific F1Limnantheshybrids. One species (L. montana) was treated as two OTUs: measurements for one OTU were taken from field collections and for the other, from garden‐grown plants. A maximum of 35 characters was used in the numerical analyses. Raw data for each character were given equal weighting by condensation. Coefficients of resemblance were established using the mean character difference (MCD) method. Tryon's clustering technique (called key communality cluster analysis) was used. Three numerical analyses of Limnanthaceae were made: one with all 35 characters (T analysis), one with 18 floral characters (F analysis), and one with 17 pre‐ or post‐anthesis or vegetative characters (V analysis). Relative positions of OTUs in the T and F analyses are substantially different from those in a conventional taxonomic treatment of the family. The V analysis shows many differences from the T and F analyses. In all analyses the two OTUs representingL. montanawere closer to other OTUs than to each other. The two hybrid OTUs showed greater resemblance to one parent than to the other and in two analyses one hybrid was not intermediate between the parents. Similarities between the T and F analyses are explained on the basis of the predominance of floral characters in both. The differences between these two analyses on the one hand and the V analysis and phylogenetic arrangement of the family on the other are attributed to parallelisms in the evolution of floral characters associated with iucreasing autogamy in each of the two phyletic lines in the family. Analyses emphasizing floral characters will place evolutionarily remotely related outcrossing OTUs together and unrelated, autogamous OTUs together. Using characters that are mostly unassociated with the breeding system the positions of OTUs in a numerical analysis are similar to their positions in a phylogenetic arrangement. The V analysis agrees best with suggestions concerning phylogenetic affinities among the taxa in the family, and provides a useful context for the generation of further evolutionary hypotheses.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06958.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

From a study of the morphology of spore forms and teliospore germination the genusEntorrhizaWeber is considered to be a synonym ofMelanotaeniumdeBary, andSchroeteriaWinter is synonymous with the earlier described genusSchizonella.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06959.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

A study of the staminate flower ofArceuthobiumprovided information on the development of the central cushion and the archesporial cells of the anther. From this study it was not possible to substantiate claims that the central cushion of the flower represents a rudimentary pistil. The archesporium of the anther was found to be unilocular from the very beginning and not derived by a breakdown of partitions and subsequent fusion of several locules as previously reported.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06960.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

Recently harvested true seed of potato frequently requires several months for complete germination. Gibberellic acid (GA3) has a pronounced effect on seed germination, but this effect is influenced by temperature. As the temperature approaches 80 F, germination decreases considerably irrespective of GA3treatment. Potato seed germination is also favored by low temperature, but constant low temperature alone does not insure complete germination of dormant seeds. More than 95% germination of dormant seeds can be obtained within a week either by application of GA3at low temperature or by diurnal alternation of temperature. A possible mechanism for control of seed germination is discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06961.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

Tree characters of 13 sets of twin and triplet hybrids from single seeds of crosses ofCitrus×Poncirusand characters of three otherCitrustwin sets are described. Evidence from tree size and habit, leaf size, shape, and thickness, and time of leafing and leaf fall indicates that these twins and triplets are probably all genetically identical within sets. Recent cytological evidence is cited which indicates that supernumerary sexual embryos can occur inCitrusby a process of budding from the primary embryo. The twin and triplet hybrids are clearly of separate origin from multiple asexual seedlings, also normally genetically identical, which arise fram cells of the nucellus in manyCitrusvarieties.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06962.x

出版商:Wiley    

年代:1968

数据来源: WILEY

摘要:

Two new chlorococcalean algae have been isolated from limestone springs and studied in axenic cultures. Their life histories have been elucidated and supplementary physiological attributes reported. The relationships of these species to previously described species of the genus are discussed, and a key to known species ofSpongiococcumis presented.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1968.tb06963.x

出版商:Wiley    

年代:1968

数据来源: WILEY