摘要:

Hypericum perforatumL. was found to have a wide range of distribution occurring on both calcareous and acidic sites. The two populations showed differential responses to macronutrients like calcium and phosphorus and micronutrients like aluminum and manganese. The acidic population showed better growth yield than the calcareous population at lower calcium levels in the medium, but at higher levels the reverse was true. The acidic population had higher uptake of calcium and phosphorus in all the different treatments and of magnesium, potassium, and sodium at low-calcium levels. The individuals of the calcareous population exhibited ‘phosphate toxicity’ at high phosphorus level in the medium while those of the acidic type gave better yield with increase in phosphorus level. Phosphorus uptake was consistently higher in the case of the acidic type compared to the calcareous population. The calcareous population was adversely affected at higher levels of aluminum and manganese and the individuals of this population exhibited severe toxicity symptoms. The acidic population gave good growth yield at both low and high levels of aluminum and manganese. The uptake of aluminum and manganese increased at higher levels of these nutrients in the media. These observations on the two populations have been discussed and it was concluded that besides the direct role of calcium, the differential response to phosphorus, aluminum, and manganese, the availability of which is determined by the pH of the soil, also control the restriction of the two ecotypes to their respective natural habitats.

ISSN:0008-4026    

DOI:10.1139/b69-021

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Incomplete walls in upper epidermal cells ofAllium cepabulb scales were found in two out of three varieties tested. Various portions of longitudinal or transverse walls are missing or present only as rim-like wall fragments

ISSN:0008-4026    

DOI:10.1139/b69-022

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

One hundred and fifty-four taxa of bryophytes, including 15 hepatics, 2 peat mosses, and 137 mosses, are reported for the 255 000 km2aspen parkland region of west-central Canada. Descriptions of the habitats and distribution of the individual taxa are given as well as species groups characteristic of the major habitat types. The following distributional elements are represented: Pan North American, 37%; Arctic–Boreal, 24%; Boreal, 21%; Eastern Boreal, 8%; Western Boreal, 1%; Cordilleran, 1%; Temperate, 5%; and Western Temperate, 1%. Only 3% of the taxa are endemic to North America.

ISSN:0008-4026    

DOI:10.1139/b69-023

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Synonymy ofDermea piceinaGroves is established and pathogenicity of this species demonstrated on balsam fir (Abies balsamea(L.) Mill.) and black spruce (Picea mariana(Mill.) BSP.).

ISSN:0008-4026    

DOI:10.1139/b69-024

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A new species ofLesquerellaendemic to the Richardson and Ogilvie Mountains of northwestern Canada is described asLesquerella CalderiMulligan and Porsild. It is tetraploid with the base numberx = 5 and is most closely related toLesquerella arctica(Wormskj.) Watson, a widespread species of the Arctic that is dodecaploid with the basex = 5.

ISSN:0008-4026    

DOI:10.1139/b69-025

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Experiments with dendrographs on trees of Japanese larch,Larix leptolepis(Sieb. & Zucc.) Gord., subjected to overlapping sawcuts, suggest that this treatment brings about a considerable change in the water status of conducting elements in the stem.

ISSN:0008-4026    

DOI:10.1139/b69-026

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Fucus vesiculosusL. plants have been grown successfully in a recirculating culture system which provides an intertidal environment.

ISSN:0008-4026    

DOI:10.1139/b69-028

出版商:NRC Research Press    

年代:1969

数据来源: NRC