摘要:

Scots pine (Pinus sylvestrisL.), and Norway spruce (Picea abies(L.) Karst.) seedlings, inoculated withSuillus bovinits(L. ex Fr.) O. Kuntze andPaxillus involutus(Batsch) Fr., were grown on sloping plastic plates in growth units. A circulating nutrient solution flowed continuously over the plates. Nutrients in balanced proportions previously found to be appropriate for conifers, were added at a specified relative addition rate, in exponentially increasing amounts. The conductivity of the solution was kept low and stable (<50 μS cm−1). No carbohydrates were added.Seedling nitrogen concentration and relative growth rate attained steady states in both inoculated and uninoculated treatments. The fungi infected the short roots within a few days and formed typical mantles and Hartig nets. This occurred in all treatments, including conditions of free access to nutrients, in which the nutrient concentration of the seedlings was optimal. The growth rate of the extramatrical mycelium was very hi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05744.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The regeneration of buds from leaves ofSaintpaulia ionanthaWendl cv. Sona and from cotyledons ofLycopersicon esculentumMill. cv. UC 105 was studied in response to continuous light and daily light pulses. The regeneration of buds from cotyledons ofLycopersicon esculentumis high under continuous red and white light. Trie effect of light may be related to phytochrome. InSaintpaulia ionanthablue light appears to be very effective. The experimental results suggest that the blue light effects involve both a blue light absorbing photoreceptor and phytochrome

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05745.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Cotyledons of conifers have a light‐independent pathway for chlorophyll biosynthesis. To investigate whether the prolamellar body of Scots pine (Pinus sylveslrisL.) is similar to the better known prolamellar body of wheat, etioplast membrane fractions were isolated from cotyledons of dark‐grown Scots pine. Dark‐grown cotyledons contained both chlorophyll and protochlorophyllide, 158 and 10 nmol (g fresh weight)’respectively, and had a chlorophyllatobratio of 4.2. The content of glyco‐ and phospholipids was 7.1 μmol (g fresh weight)1. About 40 mol % of these lipids were the specific plastid lipids – monogalactosyl diacylglycerol. digalactosyl diacylglycerol and sulfoquinovosyl diacylglycerol in the relative amounts 50, 35 and 7 mol %. The mol ratio of monogalactosyl diacylglycerol to digalactosyl diacylglycerol was 1.7. Low temperature fluorescence emission spectra of intact cotyledons and homogenate showed maxima at 633, 657, 686, 696 nm and a broad peak at 725–735 nm. The maxima at 633 and 657 nm represented different forms of protochlorophyllide and the other emission maxima represented chlorophyll protein complexes. The 657 nm form of protochlorophyllide was phototransformable both in vivo and in the isolated membranes. The phototransformable protochlorophyllide was substantially enriched in the prolamellar body fraction.The specific activity of light dependent protochlorophyllide oxidoreductase in the prolamellar body fraction was found to be 2 nmol chlorophyllide formed [(mg protein)−1min−1]. The molecular weight of the enzyme polypeptide was determined as 38 000 dalton with sodium dodecylsulphate‐polyacrylamide

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05746.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Triadimefon [1‐(4‐chlorophenoxy)‐3,3‐dimethyl‐l‐(l,2,4‐triazol‐l‐yl)‐2‐butanone] is a triazoie fungicide which protects bean (Phaseolus vulgaris L.cv. Spring Green) plants from heat and chilling injury. When the plants were exposed to heat shock by dipping the shoots in hot (50°C) distilled water for 2 min or exposing the plants to cold (1°C) for 8 h the primary leaves showed visual symptoms of injury 2 days after treatment and thereafter there was a progressive decline in chlorophyll and an increase in electrolyte leakage indicative of a loss of membrane integrity. There was a loss of metabolic (respiratory) activity in the root meristems when the roots were dipped in hot (48°C) water. All these symptoms of heat and chilling injury in the controls were either delayed or prevented by root ap

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05747.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Petiolar protoplasts of a dihaploid line of winter oilseed rapeBrassica napusL. ssp.oleiferawere exposed to fusogenic polyethylene glycol (PEG) and electric field treatments. The surface properties and stability of membrane components of the treated protoplasts were investigated by contact angle measurements in aqueous two‐phase systems and differential scanning calorimetry, respectively. The leakage of intracellular components was estimated with respect to amino acids, proteins and DNA. Both fusogenic treatments resulted in the same apparent changes in membrane surface hydrophobicity and the same destabilization of membrane components. However, the PEG‐treated protoplasts were more leaky than both the control and the electric field‐treated protoplasts. The results indicate that the molecular mechanisms of PEG‐ and electrical field‐induced fusion are similar. However, the effects of the latter appear to be less harmful presumably because the parameters for electric field treatment are more easily c

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05748.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Uptake and metabolism of [U‐14C]‐mannitol by suspension cultures ofDamns carotaL. cv. Kirodagosun andNicotiana tabacumL. cv. Wisconsin 38, and by cotyledon cultures ofPinus radiataD. Don have been studied. Uptake of label ranged from 138 to 906 nmol (g FW)−1h−1, resulting in absorption of 3 to 22% of the mannitol supplied to the cultures, over a 14 h incubation period. Of the absorbed mannitol 33 to 75% was metabolized, with label appearing in lipid, insoluble, acidic, basic, neutral and CO, fractions. No adaptation to culture with mannitol prior to the experiments was observed, but tobacco showed a decreased ability to metabolize the compound after 8 days in its presence. Because of the rates of uptake observed, and the metabolism of this compound, it is concluded that mannitol is not an ideal osmoticum for long‐term studies with any of these species, though its use in the short‐term re

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05749.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The influence exerted by the seed coat, the embryonic axis and aeration conditions on starch degradation and a‐amylase activity (EC 3.2.1.1) in lentil (Lens culinarisMedik cv. Castellana) cotyledons was studied over twelve days of seedling growth. The presence of the seed coat influenced starch degradation and amylase activity negatively. The starch content in attached cotyledons decreased with time; however, in detached cotyledons starch degradation was very slow. These differences were in accordance with the variations in dry weight. The axis exerted a promotive effect on amylase development during the first days of growth if aeration conditions were restricted. Moreover, in the last days, similar levels in attached and detached cotyledons were reached. When the detached cotyledons were placed under improved aeration conditions, the amylase levels reached were greater than under any other conditions.The low rates of starch degradation in detached cotyledons in spite of high amylase activity was not due to feed‐back inhibition of the enzyme system, but may have been due to osmotic str

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05750.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The changes in osmotic potential and cell wall composition of hypocotyl cell walls from different hypocotyl regions were investigated during growth of etiolated seedlings ofPinus pinasterAiton. The osmotic potential in the subapical 5 mm part was minimum when hypocotyl growth rate was low, and increased when the fast growth phase began. The main non‐cellulosic sugars of the cell wall from pine hypocotyl were arabinose, galactose, xylose, glucose and uronic acids, although their relative proportions were different from those found for angiosperm cell walls. Non‐cellulosic glucose was the sugar showing the most important changes during hypocotyl growth as well as along the hypocotyl, suggesting that a glucose‐rich polysaccharide is involved in a very active turnover during growth. A partial degradation of a xyloglucan during growth is sugg

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05751.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The cellular localization of β‐amylase (EC 3.2.1.2) in resting barley seeds was investigated by immunohistochemistry. The monospecificity of the antibodies used was shown by immunoelectrophoresis and western blotting. An adaptation of the immunofluorescence technique allowed the localization of β‐amylase. free of autofluorescence, in the different parts of the seed. In endosperm, there was β‐amylase protein in aleurone layers, only in the starchy endosperm, where the distribution of the enzyme was not uniform. The β‐amylase of starchy endosperm. which can be in a free or a hound form, was mainly localized around starch granules of different sizes. In the embryo. β‐amylase was present only in the part of the scutellum in front of the first leaf. By immunoquantitation after separation of the seed parts, its was shown that the ratio between the amounts of enzyme in embryo and endosperm was le

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05752.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The inhibitory effect of a short red light pulse followed by prolonged dark incubation on chlorophyll accumulation in etiolated cucumber cotyledons (Cucumis sativusL. cv. Elem) was reflected in the development of the internal membrane system of the mesophyll plastids. Dark incubation for 24 h after phytochrome activation produced the characteristic accelerating effect OB chlorophyll synthesis and chloroplast development. However, longer intervening dark periods (48, 72 and 96 h) before white light exposure resulted not only in a diminished capacity to concentrate chlorophyll, but also in an impaired ability to form grana. The absence of stacking was consistent with a high chlorophyll a to chlorophyllbratio.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05753.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY