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221.
A non-reducing trisaccharide, α-D-mannopyranosyl-(1 → 4)-α-D-glucuronopyranosyl-(1 → 2)-myo-inositol (MGI) accumulated in the spent medium of cell-suspension cultures of `Paul's Scarlet' rose (Rosa sp.) predominantly during the period of rapid cell growth. This trisaccharide was also produced by cultures of sycamore (Acer pseudoplatanus L.) but not by those of the graminaceous monocots maize (Zea mays L.) and tall fescue grass (Festuca arundinacea Schreb.). When added to cultured Rosa cells, [14C]MGI was neither taken up by the cells nor bound to the cell surface and was not metabolised extracellularly. When D-[6-14C]glucuronic acid was fed to cultured Rosa cells, extracellular [14C]MGI started to appear only after a 5-h lag period, compared with a 0.5-h lag period for labelling of extracelluar polysaccharides.
Furthermore, [14C]MGI continued to accumulate in the medium for at least 20 h after the accumulation of 14C-polymers had ceased. These observations indicate that extracellular MGI was produced from a slowly turning-over pool of
a pre-formed intermediate. Structural considerations indicate that the intermediate could be a glucuronomannan or a phytoglycolipid
(glycophosphosphingolipid). No Rosa polysaccharides could be found that generated MGI in the presence of living Rosa cells. We therefore favour phytoglycolipids as the probable biosynthetic origin of MGI.
Received: 29 April 1999 / Accepted: 13 June 1999 相似文献
222.
Both export of 14 C from the source leaves of roses (Rosa × hybrida cv. Golden Times) and import of 14 C to the petals were reduced by plant exposure to low night temperature. However, the import was affected to a greater extent than the export. During all stages of flower bud development the concentration of reducing sugars in petals of roses grown at reduced night temperature was lower than in petals of plants grown at higher night temperature. There was no significant difference in starch content in response to the night temperature, and the content of starch decreased toward complete flower bud opening. The concentration of sucrose in flowers at the low night temperature remained low during all stages of flower bud development, while at the high night temperature the concentration of sucrose increased during flower bud development, reaching a peak at the stage when petals start to unfold. At both temperatures the concentration of sucrose declined at complete flower opening. The activity of sucrose synthase (EC 2.4.1.14) was inhibited by low temperature in young rose shoots more than in the petals, while the activity of acid invertase (EC 3.2.1.26) was affected similarly in both tissues by the temperature treatments. 相似文献
223.
B. von Malek T. Debener 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(2):228-231
Diplocarpon rosae is the causal agent of rose blackspot, one of the most severe diseases of field-grown roses. The genetics of resistance to
this pathogen was investigated in crosses between tetraploid rose genotypes. The hybrid breeding line 91/100-5, which exhibits
a broad resistance to all isolates tested so far, was selfed to produce an F2 population, backcrossed to the susceptible tetraploid variety ‘Caramba’ and crossed to the susceptible varieties ‘Heckenzauber’,
‘Pariser Charme’ and ‘Elina’. Infection experiments resulted in segregation ratios consistent with the presence of a single
dominant resistance locus in the duplex configuration in the hybrid 91/100-5. This suggests, together with previous data on
the race structure of the fungus, a “gene-for-gene” type of interaction in the pathosystem Diplocarpon/Rosa. We propose to designate this gene Rdr1, which is the first resistance gene described in the genus Rosa. The advantages and limitations of such an interaction type for future rose breeding programmes and for marker-assisted selection
strategies are discussed.
Received: 29 August 1997 / Accepted: 19 September 1997 相似文献
224.
The activities of nitrate reductase and glutamine synthetase in leaves of greenhouse grown rose plants (Rosa hybrida cvs.
Ilseta and Mercedes) grafted on various rootstocks were compared with those in leaves of non-grafted, own-root plants of these
cultivars. The results obtained showed that the enzymatic activities as well as nitrate content in the leaves were altered
by the grafting and by type of the rootstock used. These rootstock-imposed alterations differed between the two cultivars
used in the study.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
225.
Montserrat Capellades Raoul Lemeur Pierre Debergh 《Plant Cell, Tissue and Organ Culture》1991,25(1):21-26
Shootlets of Rosa multiflora L. cv. Montse were cultured in vitro with four different levels of sucrose (0, 1, 3 and 5%). Chloroplasts of shootlets grown in a medium without sucrose contained numerous, large plastoglobuli and were lacking in starch granules. The size and number of starch granules increased with the level of sucrose in the culture medium. Starch content in leaves of shootlets grown with 5% sucrose was higher (ca 1, 3%) than those grown with 3% (ca 0, 45%) and 1% sucrose (ca 0, 27%). Starch might be used by the in vitro shootlets during the acclimation period.Abbreviations BA
benzyladenine
- Pi
orthophosphate
- S
sucrose
- Rubisco
ribulose 1,5-bisphosphate carboxylase
- TEM
transmission electron microscopy 相似文献
226.
Jaleh Ghashghaie Françoise Brenckmann Bernard Saugier 《Plant Cell, Tissue and Organ Culture》1992,30(1):51-57
Stomatal malfunctioning is one of the main reasons why plants desiccate when transferred from in vitro to greenhouse conditions. In order to overcome this problem in Rosa hybrida cv. Madame G. Delbard (R) Deladel, two techniques, bottom cooling and water vapour permeable lid, were used. Both methods aimed to increase the vapour pressure gradient between leaf and atmosphere and consequently to improve plant transpiration.The results showed that these techniques increased leaf resistance to dehydration and improved stomatal regulation. Water relations of treated plantlets were similar to those generally observed in hardened plants: lower leaf water and osmotic potentials, and lower leaf water content than in the control ones. Osmotic adjustment occurred in treated plantlets maintaining turgor pressure. Each technique also induced some effects on growth during the rooting phase: with bottom cooling, roots were shorter, with permeable lids, apices were necrosed.These results are discussed in terms of physiological causes and in terms of effect during the following acclimatization.Abbreviations AWC
absolute water content
- DW
dry weight
- FW
fresh weight 相似文献
227.
228.
Suspension-cultured rose ( Rosa damascena Mill. cv. Gloire de Guilan) cells irradiated with UV-C (254 nm. 558 J m−2 ) showed a transient production of H2 O2 as measured by chemiluminescence of luminol in the presence of peroxidase (EC 1.1 1.1.7). The peak concentration of H2 O2 , which occurred at about 60–90 min after irradiation, was 8–9 μ M . The time course for the appearance of H2 O2 matched that for UV–induced K+ efflux. Treatments that inhibited the UV-induced efflux of K+ , including heat and overnight incubation with cycloheximide and diethylmaleate, also inhibited the appearance of H2 O2 . The converse was not always true, since catalase (EC 1.11.1.6. and salicylhydroxamic acid, which inhibited luminescence, did not stop K+ efflux. We conclude that H2 O2 synthesis depends on K+ efflux. Because H2 .O2 in the extracellular space is required for lignin synthesis in many plant tissues, we suggest that the UV–stimulated production of H2 O2 is an integral part of a defensive lignin synthesis. 相似文献
229.
230.
Induction of nitrate reductase (EC 1.6.6.1) activity was measured in Paul's Scarlet rose cell suspensions cultured in media containing nitrate (NO
3
-
) or urea (U) as nitrogen source, and with (+Mo) or without molybdenum (-Mo). There was a lag of 30 min during induction by NO
3
-
in +Mo cultures but no lag occurred during induction after adding Mo to NO
3
-
-Mo or to U-Mo cultures preincubated with NO
3
-
. Actinomycin D, cycloheximide, and puromycin completely blocked induction by NO
3
-
, but had no effect on the initial rate of induction by Mo. Cycloheximide and puromycin blocked induction by NO
3
-
more quickly than actinomycin D. Induction by NO
3
-
appeared to involve mRNA-dependent synthesis of apoprotein followed by rapid activation with molybdenum in intact cells independently of protein synthesis. Nitrate-induced apoprotein appeared less stable than the holoenzyme. When induced by NO
3
-
in the absence of Mo, apoprotein concentration was about half the amount of maximally induced nitrate reductase. Cycloheximide stabilised preformed nitrate reductase which disappeared steadily in the presence of puromycin. Apoprotein was not stabilised by either antimetabolite.Abbreviations Mo
molybdenum
- NO
3
-
+Mo
standard, MX1 culture medium
- NO
3
-
-Mo
MX1 medium purified of Mo
- NR
nitrate reductase
- PSR
Paul's Scarlet rose
- U
urea
- U+Mo
MX1 medium with NO
3
-
replaced by urea
- U-Mo
MX1 medium with NO
3
-
replaced by urea and also purified of Mo 相似文献