The effects of long‐term water stress on water and terpene contents of the foliage of Cupressus sempervirens were studied. A great deal of water was lost over 2 months before a remarkable stabilization. A strong decrease of all the classes of terpenes accompanied this dehydration. Mono‐ and sesquiterpene hydrocarbons and free terpenols were almost entirely metabolized, whereas esters and terpene glycosides rose slightly and remained at a constant level when the water content had stabilized. Although a significant part of the mono‐ and sesquiterpene hydrocarbons was emitted in the early stage of stress application, the major part was used by the plant in response to the drought conditions.
Sea buckthorn (Hippophae rhamnoides L., fam. Elaeagnaceae) fruits are rich in pigments and lipoproteins located in membranes and the fleshy mesocarp. In spite of many reports concerning the neutral lipids in the mesocarp, no data about the polar lipids and their fatty acid composition are available even though they play important structural and physiological roles in cell membranes and may offer interesting applications as emulsifiers and nutrients in cosmetic preparations. Carotenolipoprotein complexes are located particularly in fruit membranes where polar lipids may function as bridge compounds between the polar (protein) and non-polar (carotenoid) moieties. The fatty acid compositions of total and individual polar lipids separated from carotenolipoprotein complexes were determined by HPTLC and GC. The polar lipids included 61% phospholipids and 39% galactolipids, which contained mainly 16:0, 16:1 (9c), 18:1 (9c), 18:1 (11c) and 18:2 (9c, 12c) fatty acids. Almost all polar lipids showed high ratios of 16:0/16:1 (11c) and 18:1 (9c)/18:1 (11c), and higher quantities of 18 carbon unsaturated fatty acids than of the saturated analogue. Galactolipids proved to be richest in 18:1 (9c) and 18:3 (9c, 12c, 15c) fatty acids, while phospholipids contained higher concentrations of 16:0 and 18:1 (9c).
In vitro plantlet regeneration will be a sueful tool in reforestation only when rooting problems are overcome. Our study was therefore focused on Pinus pinaster rooting conditions. Methods were used which permit multiple axillary (instead of adventitious) bud production in order to obtain genetically identical explants and hence to procure more homogeneous resutls. The hormonal treatment efficiency was then tested on several clones for rooting. Different substrates were compared. A mixture of peat and perlite (1/3, v/v) permitted rooting and the further development of the root system if humidity was properly controlled. The use of an agar medium avoided this difficulty; it supported root induction but resulted in limited growth. For hormonal treatment, explants, submitted to a 12‐day‐period with NAA (10−6M) and then subcultured in an auxin‐free medium, gave rooting percentages ranging from 80 to 100%. In terms of rooting quality (intensity, growth rate and branching ability), a 15‐to 19‐day‐period of auxin treatment was more effective. Application of this optimal treatment to several clones revealed slight differences within clones and between clones (80 to 100% of rooting according to the clone). Regenerated plantlets were able to undergo an autotrophic growth after transplantation under greenhouse conditions.
SUMMARYSeedlings, axillary buds and apical root meristems of Pine (Pinus pinaster Sol.) were used in different controlled environments. A kinetic study of root morphogenesis was performed, supported by light and electron microscopic analysis.Without any symbiotic or parasitic fungus, short roots (histologically similar to the ectomycorrhizae except for the absence of the fungus), able to produce dichotomous branches, were observed on all the kinds of explant and in all the environmental conditions used. Hence the formation of these mycorrhizogenic short roots is 'genome dependent'.In clones of young plantlets (produced by vegetative propagation by means of axillary budding in vitro), the root systems exhibit a similar intensity, strong or weak, to dichotomize; this emphasizes the relationships between the formation of mycorrhizogenic short roots and the pinus genome.This study seems to be the first attempt to demonstrate, under controlled conditions, a direct relationship between plant genome and root branching in a woody species.
1983. Isolation and culture of gymnosperm root protoplasts (Pinus pinaster). -Physiol. Plant. 59; 359-362.Various factors affecting the yield and isolation of axenie protoplast cultures originating from Pinus pinaster root segments (in whieh most cells are differentiating) were studied. In spite of the use of plant material eolleeted from germinating seeds under aseptic conditions, an additional sterilization with 0.1 % w/v mercuric chloride in 50% ethanol was a prerequisite for obtaining an axenic protoplast culture. A pretreatment with 30 mA/ eysteine in 0.7 M sorbitol for 1 h tripled the yield. Centrifugation at 100g instead of 40g further increased the yield to 6 x KP protoplasts per cm of root segment. Viability ranged from 80 to 917o. Cell divisions occurred after a minimum of 7 days of culture.Additional key word -Cysteine.
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