摘要:

The photosynthetic activity of three sciaphilous algae (including two cavernicolous ones) was measured with a Clark electrode in the air, by light minus dark differences in the rates ofunder laboratory and near natural physical conditions. Photosynthesis versus light intensity curves showed a sharp slope at low light and a suddenly lower slope at medium intensities; this is interpretable as the Kok effect. This phenomenon is stronger with cavernicolous algae than with less sciaphilous plants. High yield activity of the three studied algae was observed only in the naturally encountered range of light intensity. A seasonal adaptation of light activity was shown but not a daily one.

ISSN:0008-4026    

DOI:10.1139/b85-267

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

A calendar of reproductive events is established inEragrostis tef(Zucc.) Trotter, a sexual tetraploid Ethiopian cereal, using the microsporogenesis and microgametogenesis as reference scales to which the female gametophytogenesis is related. The absolute frequency is noted for each correlation brought out (microgametogenesis–megagametogenesis). The frequencies of all the female stages found at a same level of anther development are also specified. This preliminary work is done within the scope of an interspecific hybridization program which aims at transferring, toE.tef, genes responsible for the apomictic character present in the genus.

ISSN:0008-4026    

DOI:10.1139/b85-268

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The primary thickening meristem inCordyline terminalis(L.) Kunth was found to be continuous with the secondary thickening meristem in vegetative shoots. This could be seen in longitudinal and transverse sections stained with azure B, aniline blue–black, or safranin and fast green. The primary thickening meristem was a wide zone in the crown, and initial cells were arranged in anticlinal files which were continuous from an area within the central cylinder to the outer cortex. The secondary thickening meristem was narrow in radial extent and consisted of initial cells which were arranged in short, anticlinal files. When vascular bundles were followed (and plotted) acropetally from serial transverse sections starting with groups of anastomosing secondary bundles, secondary bundles were continuous with both major and minor axial primary bundles or with procambial strands. All bundles were collateral in the crown but became amphivasal in the intermediate region of the central cylinder and remained so in the secondary tissue. Procambial strands ran along or within the thickening meristem at all levels of the stem. These observations lead us to believe that inCordyline terminalis(i) the primary and secondary thickening meristems function as a single entity and (ii) the primary and secondary bundles describe a single, continuus vascular system.

ISSN:0008-4026    

DOI:10.1139/b85-269

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The formation of crystals rich in inorganic reserves was studied during the embryogenesis ofRaphanus. Some crystals and globoids were detected in thin green cotyledons during the early phase of embryonic curvature. After a double fixation, a few crystals were distinct inside the intracytoplasmic developing protein bodies. After a single aldehydic fixation, dark crystals and globoids with or without crystals were observed; these structures multiplied quickly inside the maturing protein bodies. In prints derived from thin green cotyledons, various types of crystals similar to those derived from dry seeds were isolated. Microanalyses with X-ray spectrometry by wavelength dispersion show that the major sorts of crystals usually found in dry seeds were precociously formed. Depending on the case, they were rich in phosphorus, calcium, silicon, or iron. The elemental composition of each type was defined. In ultrathin sections, dark transitory threads with crystals or globoids were observed in some developing protein bodies. Some similar dark threads were obtained in prints without fixation. In addition, these could contain very small granules (diameter, 20 nm). These threads, although rich in phosphorus and calcium, had an elemental composition different from that of the enclosed crystals.

ISSN:0008-4026    

DOI:10.1139/b85-270

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

Genetically marked and wild-type haploid cultures ofTilletia carieswere mixed and used as inocula to analyze their potential for heterokaryon formation in the susceptible spring wheat variety 'Red Bobs' (Triticum aestivumL.). Of the fungus-treated plants inoculated by hypodermic needle injection into the boot at the flag leaf stage, 30 to 64% proceeded to maturity; the remainder failed to head.Tilletia carieswas recovered from each of 38 representative plants which failed to head and from 3 plants which headed but showed no visible signs of infection. None of the inoculations resulted in teliospore formation within mature heads or other plant tissues. Genetic analysis of hyphal fragments obtained from mycelium in infected plants indicated that a heterokaryon had formed in each of two pairings of different auxotrophic strains of the fungus. The number of nuclei present in hyphal cells was variable. However, secondary sporidia derived from the heterokaryon were mononucleate with one exception and exhibited the nutritional requirement of one or the other parental strain. Results are discussed in relation to the development of a system for mitotic and meiotic analysis of single gene traits in the bunt fungi.

ISSN:0008-4026    

DOI:10.1139/b85-271

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

In Canada,Ptelea trifoliataL. (Rutaceae) is restricted in its natural distribution primarily to the Lake Erie shoreline. Although it is locally successful as a colonizing species, it appears inhibited from either exploiting a large area of shoreline habitat or extending its range inland. The morphological descriptions of the hop tree's sexual expression have been ambiguous; however, our observations show this species to be clearly dioecious, with only about 2% of the otherwise male plants producing a few hermaphroditic flowers, and fruit. The sex ratio is strongly skewed toward the males, which produce more and showier inflorescences than female plants. Despite this, the insect visitation rates are not significantly different between the sexes. For pollination, the hop tree is a polyphilic generalist, dependent on a diverse array of insects, including short-tongued bees, wasps, and flies. It is totally dependent on wind-dispersed seeds for establishment, lacking the ability to grow clonally. In a dioecious species of disturbed habitats, this is exceptional.

ISSN:0008-4026    

DOI:10.1139/b85-272

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

Ozone response ofSolanum tuberosumL. leaf protoplasts was characterized to better understand the cellular effects of this important air pollutant. 'Norchip' and 'Cherokee' potato cultivars relatively tolerant of and sensitive to ozone, respectively, were studied. Protoplasts were exposed to ozone, air, or oxygen for 0, 1, 3, 5, 10, or 15 min. Two criteria, lysis and fluorescein diacetate staining, were used to measure protoplast response. Protoplasts exposed to ozone exhibited a significant increase in lysis and reduction in fluorescein diacetate staining during the first 10 min of exposure. During the following 5 min there were no further significant changes in lysis or fluorescein diacetate staining. The two ozone responses paralleled each other, probably reflecting two different nonsequential cellular effects. Neither oxygen nor air elicited the protoplast responses observed after ozone exposure. The relative differences in ozone response observed in intact plants of 'Norchip' and 'Cherokee' were not observed in experiments performed with protoplasts of these cultivars. The experimental results reported herein illustrate the importance of the plasma membrane to the ozone response but do not support its role in explaining the differential tolerance of the two potato cultivars studied.

ISSN:0008-4026    

DOI:10.1139/b85-273

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

A Kontron MOP system (electromagnetic electronic image analyser with built-in microprocessor system) was used for the quantitative microscopic analysis of trunks from sycamore maple and elm. It was established that the radial sizes of the derivative cells (mainly wood fibres) from each single cambium mother cell occur in a wave pattern over time which is not identical with the growth ring changes. Trachea appear regularly in the troughs in the sycamore maple and in the peaks in the elm. The author traces the well-known diverse nature of cambial production back to the most simple and antagonistic basic characteristics of cambial activity. This enables the construction of an encompassing variation system using code words for the distinct characterization of all possible wood structures and classification according to dynamic-cambial combinations. Furthermore, the existence of function-determining factors which move along the cambium may be regarded as proven on the basis of the analysis. The appearance can be explained according to the so-called "rhythmic profactor theory," which enables the construction of all possible wood structures through the appropriate combination of only a few rhythmic (harmonic) oscillation components in model systems.

ISSN:0008-4026    

DOI:10.1139/b85-274

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The leghemoglobins from a genetically diverse selection of 69 cultivated soybean (Glycine max(L.) Merr.) cultivars and plant introductions and 18 wild soybean (Glycine sojaSieb. & Zucc.) plant introductions all consist of the same set of major leghemoglobins (a,c1,c2,c3), as determined by analytical isoelectric focusing. The conservation of both leghemoglobin heterogeneity and also all four major leghemoglobin structures provides strong circumstantial evidence that leghemoglobin heterogeneity is functional.Glycine maxandG.sojaproduced the same leghemoglobins in the presence ofBradyrhizobium japonicum(Kirchner) Jordan and in the presence of fast-growingRhizobium japonicum.

ISSN:0008-4026    

DOI:10.1139/b85-275

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

Morphological descriptions, chromosome numbers, and meiotic behaviour are presented for nine different hybrids ofCarexin sectionsCryptocarpaeandPhacocystisfrom northeastern North America, mainly salt-marsh species from the St. Lawrence estuary and gulf. They areC.aquatilis×subspathacea(2n = 79),C.nigra×subspathacea(2n = 81, 83),C.nigra×salina(2n = 80),C.paleacea×salina(2n = ca. 74, 75),C.aquatilis×recta(2n = 74),C.nigra×recta(2n = 78, 79),C.paleacea×recta(2n = 73),C.aquatilis×paleacea(2n = 74), andC.nigra×paleacea(2n = 78 + fragment, 79). Hybrids showed a mixture of morphological characters from both putative parent species, and chromosome numbers were mostly intermediate between those of their parents. Meiosis of hybrids was disturbed with variable numbers of univalents, trivalents, and quadrivalents, such as in two of the parent species,C.salinaandC.recta. In general, hybrids differed from parent species by the frequent occurrence of desynaptic bivalents and higher numbers of trivalents. Pollen stainability was low in hybrids (10.0–56.6%, with two exceptionally high values of 71.8 and 92.2%). Pollen stainability was also low though quite variable inC.salina(23.7–62.8%) andC.recta(16.2–80.7%), but it was much higher inC.paleacea(92.7–100%),C.nigra(63.1–92.9%), andC.aquatilis(78.0–97.2%). Almost all hybrids and parents produced some well-formed achenes. A formula indicating the maximum affinity pairing (MAP formula) and two euploidy indexes were used to compare hybrid individuals and their parent species.Carex salinaandC.rectaare cytologically considered of hybrid origin, but they behave ecologically as stable species.

ISSN:0008-4026    

DOI:10.1139/b85-276

出版商:NRC Research Press    

年代:1985

数据来源: NRC