Larix laricina

A number of diterpenes are known to be active against herbivores ( ). The diterpenes abietic, dehydroabietic, 12-methoxy-abietic, sandaracopimaric, and isopimaric acid serve as feeding deterrents for the larch sawfly, Pristiphora erichsonii in single needles from new shoots of tamarack (Larix laricina) (133). The larvae of this insect do eat tufted needles on short shoots of the same trees. 

Another developmental hormone is the juvenile hormone, which predominates early in larval life later ecdysone predominates. It is a methyl ester of the epoxide of a fatty acid derivative, and there is some evidence that its structure differs in different groups of insects. By a series of coincidences, it was discovered that certain paper toweling prevented the European bug, Pyrrhocoris apterus, from developing into sexually mature adults. Instead, an extra one or two larval molts ensued, and all eventually died without being able to complete metamorphosis. The juvenility factor was traced to particular conifers used in American paper pulp, mainly Abies balsamea, Tsuga canadensis, Taxus brevifolia, and Larix laricina. The active principle was isolated and characterized. It... 

Fig. 1-13. Transverse section of earlywood tracheids in tamarack (Larix laricina), showing the middle lamella (M), the primary wall (P), and the outer (S,), middle (S.), and inner (S i) layers of the secondary wall. Transmission electron micrograph. Courtesy of Dr. T. E. Timell.

Arabinogalactan occurs as a white to yellow-white, coarse or fine powder. It is the dried water extract from the wood of the larch trees Larix occidentalis and Larix laricina (Fam. Pinaceae). It is a highly branched polysaccharide that has a molecular weight of 15,000 to 60,000 daltons and is composed of galactose units and arabinose units in the approximate ratio of 6 1. It is freely dispersible in hot or cold water. It is insoluble in alcohol. 

Cdtd WA Jr, Day AC, Timell TE (1968) Studies on compression wood VII. Distribution of lignin in normal and compression wood of tamarack Larix laricina (Du Roi, K Koch). Wood Sci Technol 2 13-37... 

The northern part of this region is covered with Pre-Tundra Spruce, Larch-Spmce and, at places. Larch Thin Forest and Black Coniferous North Taiga Forest ecosystems, in which Picea mariana and Picea canadensis predominate. Abies balsamea, Larix laricina are mixed with these, and birch and aspen are also found. This part lies in the permafrost area and permafrost features determine the development of biogeochemical process Cb is equal to 8.5, Ct, to 0.35 and Cbr, to 3.0. 

European larch Larix laricina 1 5.7 17 -35 water 16 linear 319 ... 

American larch Larix laricina (Du Roi) K. Koch P. apterus Sth instar larvae Topical ++ 83... 

Additional information about seed dispersal is contained in the fossil record. Dispersal events can be inferred wherever there is evidence that populations were founded at large distances from the source population. It is, of course, technically difficult to detect a small population using fossil pollen or macrofossils, and even more difficult to demonstrate that the small population was isolated from the main population (Davis et al., 1991). Pollen studies in Sweden, however, record the establishment of individual colonies of beech (Fagus sylvatica) in the late Holocene (Bjorkman, 1996) and macrofossils demonstrate that populations of spruce (Picea abies) grew far in advance of the expanding species front for thousands of years (Kullman, 1996). East of James Bay, Canada, small colonies of larch (Larix laricina) have become established in patches during the past 1500 years as the population has expanded. Some of these colonies have fused into a continuous distribution. 

Proliferated, bisporangiate, and other atypical cones occurring on young, plantation-grown Larix laricina. Canadian Journal of Botany, 64, 469-475. 

Isolated from partial acid hydrolysates of Virgilia oroboides, Anogeissus schimperi, Prunus persica, Opuntia ficus-indica (Indian fig) gums and Larix decidua e-galactan and Larix laricina arabogalac-tan. Needles (MeOH aq.). 

CigH320,6 504.441 Present in the partial hydrolysate of an arabinogalactan from Tamarack (Larix laricina) isol. from subabul (Leucaena leucocephala) gum. Constit. of the hydrolysate of a cashew-nut shell polysaccharide. 

Niemann, G. J. Phenolic glucosides from needles of Larix laricina. Phytochemistry... 

Nair G V, Rudloff E v 1959 The chemical composition of the heartwood extractives of tamarack Larix laricina K. Koch). Can J Chem 37 1608-1613... 

Eysteinsson, T. and M.S. Greenwood. 1995. Flowering on long and short shoots of Larix laricina in response to differential timing of GA4/7 applications. Tree Physiol. 15 467-469. 

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