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31.
Martino Orrù Efisio Mattana Hugh W. Pritchard Gianluigi Bacchetta 《Annals of botany》2012,110(8):1651-1660
Background and Aims
The importance of thermal thresholds for predicting seed dormancy release and germination timing under the present climate conditions and simulated climate change scenarios was investigated. In particular, Vitis vinifera subsp. sylvestris was investigated in four Sardinian populations over the full altitudinal range of the species (from approx. 100 to 800 m a.s.l).Methods
Dried and fresh seeds from each population were incubated in the light at a range of temperatures (10–25 and 25/10 °C), without any pre-treatment and after a warm (3 months at 25 °C) or a cold (3 months at 5 °C) stratification. A thermal time approach was then applied to the germination results for dried seeds and the seed responses were modelled according to the present climate conditions and two simulated scenarios of the Intergovernmental Panel on Climate Change (IPCC): B1 (+1·8 °C) and A2 (+3·4 °C).Key Results
Cold stratification released physiological dormancy, while very few seeds germinated without treatments or after warm stratification. Fresh, cold-stratified seeds germinated significantly better (>80 %) at temperatures ≥20 °C than at lower temperatures. A base temperature for germination (Tb) of 9·0–11·3 °C and a thermal time requirement for 50 % of germination (θ50) ranging from 33·6 °Cd to 68·6 °Cd were identified for non-dormant cold-stratified seeds, depending on the populations. This complex combination of thermal requirements for dormancy release and germination allowed prediction of field emergence from March to May under the present climatic conditions for the investigated populations.Conclusions
The thermal thresholds for seed germination identified in this study (Tb and θ50) explained the differences in seed germination detected among populations. Under the two simulated IPCC scenarios, an altitude-related risk from climate warming is identified, with lowland populations being more threatened due to a compromised seed dormancy release and a narrowed seed germination window. 相似文献32.
Seed germination (effects of light, temperature, NaCl and KNO3) of the coastal endangered species Crucianella maritima was investigated by testing seeds from three different populations. Data were analyzed by means of Generalized Linear Mixed Model (GLMM). The principal results showed that germination of C. maritima seeds was characterized by photoinhibition, absence of primary dormancy and salt-induced secondary dormancy, with no need for high nutrient availability (KNO3). Intraspecific differences in germination pattern emerged, apparently due to a different seed mass. These results show important germination traits of C. maritima which should be taken into account in possible reintroduction attempts aimed at restoring threatened populations of this species. 相似文献
33.
Dissecting seed dormancy and germination in Aquilegia barbaricina,through thermal kinetics of embryo growth 下载免费PDF全文
M. Porceddu E. Mattana H. W. Pritchard G. Bacchetta 《Plant biology (Stuttgart, Germany)》2017,19(6):983-993
- Threshold‐based thermal time models provide insight into the physiological switch from the dormant to the non‐dormant germinating seed.
- This approach was used to quantify the different growth responses of the embryo of seeds purported to have morphophysiological dormancy (MPD) through the complex phases of dormancy release and germination. Aquilegia barbaricina seeds were incubated at constant temperatures (10–25 °C) and 25/10 °C, without pre‐treatment, after warm+cold stratification (W+C) and GA3 treatment. Embryo growth was assessed and the time of testa and endosperm rupture scored. Base temperatures (Tb) and thermal times for 50% (θ50) of embryo growth and seed germination were calculated.
- W+C enabled slow embryo growth. W+C and GA3 promoted rapid embryo growth and subsequent radicle emergence. The embryo internal growth base temperature (Tbe) was ca. 5 °C for W+C and GA3‐treated seeds. GA3 treatment also resulted in similar Tb estimates for radicle emergence. The thermal times for embryo growth (θe50) and germination (θg50) were four‐ to six‐fold longer in the presence of GA3 compared to W+C.
- A. barbaricina is characterised by a multi‐step seed germination. The slow embryo growth during W+C reflects continuation of the maternal programme of development, whilst the thermal kinetics of both embryo and radicle growth after the removal of physiological dormancy are distinctly different. The effects of W+C on the multiphasic germination response in MPD seeds are only partially mimicked by 250 mg·l?1 GA3. The thermal time approach could be a valid tool to model thermal kinetics of embryo growth and radicle protrusion.
34.
M C Carta A Mattana M Camici S Allegrini M G Tozzi F Sgarrella 《Biochimica et biophysica acta》2001,1528(2-3):74-80
Uptake and catabolism of purine nucleosides have been commonly considered as means to salvage the purine ring for nucleic acid synthesis, usually neglecting the destiny of the pentose moiety. With the aim to ascertain if deoxyribose derived from exogenous DNA can be utilised as a carbon and energy source, we studied the catabolism of exogenous deoxyinosine in a cell line derived from human amnion epithelium (WISH). Intact WISH cells catabolise deoxyinosine by conversion into hypoxanthine. The nucleoside enters the cell through a nitrobenzylthioinosine-insensitive equilibrative transport. Deoxyinosine undergoes a phosphorolytic cleavage inside the cell. The purine base diffuses back to the external medium, while the phosphorylated pentose moiety can be further catabolised to glycolysis and citric acid cycle intermediates. Our results indicate that the catabolism of the deoxynucleoside can be considered mainly as a means to meet the carbon and energy requirements of growing cells. 相似文献
35.
Macrophages may modulate mesangial expansion following renal injury via secretory products. We undertook the present study to determine the effects of macrophages supernatants on mesangial cell proliferation. Macrophage supernatants collected in serum-free media after 24 hours caused significantly enhanced mesangial cell proliferation in long-term culture at concentration up to 50% but caused suppression at higher concentration (control, 122,000 ± 14,000 cells/well: 50% supernatant, 188,000 ± 15,100 cells/well, p < 0.02 compared to control, n = 4; 80% supernatant, 52,000 ± 3,500 cells/well, P < 0.01 compared to control, n = 4). In short-term culture [3H] thymidine incorporation, a measure of DNA synthesis, was significantly enhanced compared to control at supernatant concentrations up to 30% (30% supernatant, 4,120 ± 310 cpm/well; control, 3,210 ± 97 cpm/well, P < 0.5, n = 4), but uptake was reduced at high concentration (80% supernatant, 2,900 ± 74 cpm/well; control, 3,210 ± 97 cpm/well, P < 0.05, n= 4) When macrophages supernatants were collected after 48 hours incubation and incubated with mesangial cells, mesangial cell thymidine uptake was significantly suppressed compared to control (48-hours supernatant, 4,060 ± 260 cpm/well; control, 5,890 ± 270 cpm/well, P < 0.01, n = 4) and comapared to 24-hour supernatants, which enhanced uptake (24-hour supernatant, 8,080 ± 340 cpm/well; control, 5,890 ± 270 cpm/well, P < 0.01, n =4). Our results suggest that macrophages supernatants can directly enhance mesangial cell proliferation in vitro in both short-term and long-term culture, though this effect is lost at high concentrations of supernatant. These data lend support to the potential role of the macrophage in mediating mesangial expansion following renal injury. © 1993 Wiley-Liss, Inc. 相似文献
36.
Remo Reggiani Monica Mattana Nicoletta Aurisano Alcide Bertani 《Physiologia plantarum》1993,89(3):640-643
Nitrate present in rice caryopses can be reduced to ammonium and the ammonium subsequently assimilated by the coleoptile during anaerobic germination. All the enzymes of nitrate reduction and ammonia assimilation are present in the coleoptile. The supply of 15 NO3 confirms that the nitrate nitrogen is anaerobically incorporated into amino acids. Under anoxia, nitrate and nitrite reductase activities are increased in the coleoptile by exogenous nitrate. The importance of nitrate utilization during the anaerobic germination of rice caryopses is discussed. 相似文献
37.
Abscisic acid induced stress-like polyamine pattern in wheat seedlings, and its reversal by potassium ions 总被引:1,自引:0,他引:1
Nicoletta Aurisano Alcidc Bertani Monica Mattana Remo Reggiani 《Physiologia plantarum》1993,89(4):687-692
In 3-day-old wheat ( Triticum aestivum L. cv. Marinat) seedlings, 100 μ M ABA blocked the growth and altered the level of K+ in both the shoot and root. The presence of ABA increased the putrescine titer during a 24-h treatment. Increasing the endogenous level of K+ by the addition of 10 m M KCl to the ABA-treated seedlings, inhibited the effect of ABA on growth and putrescine level. In both tissues, ABA increased putrescine content at low concentrations (1 μ M ), reaching the maximal effect at 100 μ M . Putrescine increase induced by ABA was inhibited by both α-difluoromethylarginine (DFMA) and α-difluoromethylornithine (DFMO) in shoots while only the inhibitor of arginine decarboxylase was effective in the root. The presence of ABA modulated, in opposite ways, ornithine and arginine decarboxylase activities. These results are discussed in relation to ion balance under stress. 相似文献
38.
Protein oxidation occurs in aging and in various inflammatory conditions. Glomerulosclerosis is characterized by an accumulation of extracellular matrix (ECM) proteins and a paucity of glomerular mesangial cells and can be seen as an end-result of glomerular injury and in aging. ECM accumulation is the net result of the balance between synthesis and degradation. ECM may become oxidized as a part of inflammatory renal injury and with aging. We evaluated the hypothesis that oxidation of mesangial ECM could alter its susceptibility to the action of ECM degrading enzymes. Radiolabeled mesangial ECM was generated by growing cells on tissue culture plastic and incubating with [3H]proline. After removal of cells, leaving behind ECM, selected wells were oxidized using a FeCl3/EDTA/ascorbate system or treated under control conditions. The control and oxidized matrices were then incubated with concentrated supernatants from mesangial cells containing the major mesangial ECM degrading enzyme, the matrix metalloproteinase-2, whose activity was confirmed by gelatin substrate zymography. Counts released corresponding with ECM degraded were measured. ECM oxidized with this system was significantly less susceptible to degradation compared to control ECM. To confirm that this effect was specifically due to oxidative modification of the ECM rather than changes unrelated to oxidation we coincubated ECM with the oxidizing system plus the radical spin trap N-tert-butyl-alpha-phenylnitrone (PBN). PBN treatment was able to prevent the impaired susceptibility to degradation induced by exposure to the oxidizing system. Exposure of ECM to milder oxidative stress, however, modestly enhanced susceptibility to degradation. These data suggest that oxidation of mesangial ECM can modulate its susceptibility to degradation. This may account for the development of ECM accumulation and glomerulosclerosis in inflammatory renal injury and in aging. 相似文献
39.
Andrea Santo Efisio Mattana Luca Frigau Gianluigi Bacchetta 《Plant Species Biology》2014,29(3):300-305
Phleum sardoum is an endemic psammophilous species of Sardinia, growing exclusively on coastal sandy dunes. The effect of glumes on seed germination, germination requirements at constant (5–25°C) and alternating (25/10°C) temperatures, both in the light (12/12 h) and in the dark were evaluated, as well as the effect of a dry after‐ripening period (90 days at 25°C), the salt stress effect (0–600 mmol NaCl) and its recovery on seed germination. The presence of glumes reduced final germination percentages. For fresh naked seeds, high germination percentages were observed at 10°C. Dry after‐ripening increased germination rate at low temperatures, but did not affect final germination percentages. NaCl determined a secondary salt‐induced dormancy which recovery interrupted only partially. Our results highlighted that this species has its optimum of germination during autumn–winter when, under a Mediterranean climate, water availability is highest and soil salinity levels are minimal. 相似文献
40.
Massimo Confalonieri Roberto Borghetti Anca Macovei Claudia Testoni Daniela Carbonera Manuel Pedro Salema Fevereiro Caius Rommens Kathy Swords Efisio Piano Alma Balestrazzi 《Plant cell reports》2010,29(9):1013-1021
In the present work, Agrobacterium tumefaciens-mediated genetic transformation of the model legume Medicago truncatula Gaertn. (barrel medic) was carried out using the pSIM843 vector that contains a Medicago-derived transfer DNA, delineated by a 25-bp sequence homologous to bacterial T-DNA borders. The transfer DNA contains an
expression cassette for the nptII (neomycin phosphotransferase) gene and is flanked by an expression cassette for the backbone integration marker gene ipt (isopentenyl transferase). Our results demonstrate that the Medicago-derived RB-like elements efficiently support DNA mobilization from A. tumefaciens to M. truncatula. Kanamycin-resistant shoots with normal phenotype and ipt-shooty lines were recovered at a frequency of 11.7 and 7.8%, respectively. Polymerase chain reaction (PCR) analyses demonstrated
that 44.4% of the independent transgenic lines were backbone-free and evidenced the occurrence of backbone-transfer events. 相似文献