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1.
rogen removal from the liquid steel.The experimental results show that addition of BaO and TiO2 to the slag can promote removal of nitrogen,and the nitrogen content of molten steel decreases linearly with increasing BaO and TiO2 contents in the slag.liquid steel;nitrogen content;BaO  相似文献   

2.
《Scientia Horticulturae》1986,28(3):289-298
Petunia × hybrida Hort. Vilm.-Andr. ‘Coral Sea’ stock plants were grown with a modified Hoagland's solution to determine the effect of stock plant N and Ca nutrition on subsequent leaf explant and anther growth in vitro. In separate experiments, N was 0, 75, 150 or applied at 0, 100, 200 or 400 mg 1−1 as nitrate-N, and Ca was applied at 300 mg 1−1. Leaf explants from plants grown with 100 mg 1−1 N produced the greatest amount of callus, while those from plants grown with 200 and 400 mg 1−1 N produced the highest number of shoots. Nitrogen treatments increased the anther fresh weight and the number of shoots per culture compared to anthers derived from stock plants that did not receive N.The fresh weight of shoots produced by leaf explants decreased with increasing Ca concentrations applied to stock plants. Anthers derived from stock plants treated with 0 mg 1−1 Ca produced the highest number of shoots per culture.Anatomically, both filament and anther wall tissue produced callus, but no callus production from microspores was observed. Organs produced by anthers were diploid.  相似文献   

3.
Ning G.  Ma Z.  Mao J.  Li W.  Wang Y.  Hu Z.  Shi X.  Chen B. 《果树学报》2019,(9):1150-1160
【Objective】As an essential mineral element in plant growth and development, nitrogen has irreplaceable roles in organ construction, nutritive metabolism, biochemical processes as well as fruit yield and quality. The quality and yield of grapes are greatly influenced by the amount of nitrogen applied. In recent years, the industry of China's wine grape has developed rapidly, but there are problems with unreasonable fertilization in production. The Gansu Corridor has the climatic conditions and geographical resources suitable for producing high-quality wine grapes. However, wine grapes are extensively planted on a sandy loam soil with low organic matter. In the actual production, chemical fertilizers are often applied to ensure the normal growth and development of the grapes. At the same time, water-saving agriculture has become the demand for agricultural development in this area. The aim of our study is to investigate the effects of nitrogen application rates on key enzyme activities and related gene expression during nitrogen metabolism, so as to further provide a theoretical reference for the application of nitrogen in wine grape growing in the Gansu Corridor. 【Methods】The experiment was carried out in a 10-year-old‘Cabernet Gernischet’vineyard of the Mo Gao located in Wuwei City from 2014 to 2015. All the grapevines were planted from west to east with simple hedge-shape. The planting spacing was 0.7 m×3.0 m. The area of the plot was about 240 m2, and each plot contained 40 plants. During the test period, the irrigation was carried out according to the“Wuwei Mo Gao Brewing Grape Drip Irrigation Water Distribution Quota”, which formulated by the research team. The irrigation amount in the bud break stage was 675 m3·hm-2, the flowering stage was 900 m3·hm-2, the first berry swell period was 900 m3·hm-2, the secondary shoot growth period was 150 m3·hm-2, and the second berry swell period was 600 m3 · hm- 2, and overwintering water was 1 275 m3 · hm- 2. The total irrigation amount during the whole growth period was 4 500 m3·hm-2. Five different application amounts of nitrogen (0 kg·hm-2, 150 kg·hm-2, 300 kg·hm-2, 450 kg·hm-2 and 600 kg·hm-2, characterized as CK、N1、N2、N3 and N4, respectively) were applied with a completely randomized block. Urea was used as external nitrogen and applied with water. The 750 kg·hm-2 of calcium superphosphate was applied before the first irrigation during the soil excavation. The 825 kg·hm-2 of potassium sulfate was applied in fruit color-changing period. Effects of nitrogen application rates on total nitrogen content, soluble protein content, key enzyme activities including nitrate reductase(NR), glutamine synthetase(GS), glutamate synthase(GOGAT) and glutamate dehydrogenase(GDH) as well as the related gene expression levels in leaves (VvNR1, VvGS1, VvGOGAT1 and VvGDH1) were determined at different developmental stages (5th day before anthesis, 20th day after anthesis, 50th day after anthesis, 80th day after anthesis). Ten to fifteen leaves were collected from each treatment. Fresh leaves were punched out with a punch and 1.0 g was weighed for determination of soluble protein content and enzyme activity assay with 3 replicates. The new leaves without pests and diseases on the top of the current shoots were selected to extract RNA. 2.0 g of grape leaves wrapped in tin foil were placed in a liquid nitrogen tank and stored in arefrigerator at -80℃ for RNA extraction. 【Results】The results showed that nitrogen application significantly increased the net photosynthetic rate in leaves. The treatment of N2 significantly increased leaf area and the total nitrogen content in leaves in comparison with CK 5th day before anthesis, 20th day after anthesis and 80th day after anthesis. The soluble protein content increased by nitrogen application in leaves on 80th day after anthesis. The NR activity in leaves showed an increasing trend with the increase of nitrogen application in the range of 0 to 300 kg on 5th day before anthesis, 20th day after anthesis and 80th day after anthesis. The GS activity in leaves increased significantly by N2 treatment on 5th day before anthesis, 50th day after anthesis and 80th day after anthesis, which were 1.66, 1.25 and 1.34 times more than the control, respectively. The GOGAT activity in leaves increased significantly by N2 treatment on 5th day before anthesis and 80th day after anthesis, 0.53 and 0.42μmol·g-1·min-1, respectively. Compared with CK, N2 and N3 treatments could improve the GDH activity in leaves during the whole growing period. The expression level of VvNR1 in N2 treatment was significantly higher than CK and other nitrogen treatments on 5th day before anthesis, 20th day after anthesis and 80th day after anthesis. VvGS1 was significantly up-regulated by N1 and N2 on 5th day before anthesis, which was up-regulated by 142.33% and 283.47% in comparison with CK, respectively. VvGDH1 was up-regulated during the whole growing period after nitrogen application. With N2 treatment, fruit soluble sugar, the ratio of sugar to acid, tannins, anthocyanin content reached the maximum, the titratable acid content was the lowest, the yield was at a medium level. 【Conclusion】The results suggested that different nitrogen application rates affected the expression of VvNR1, VvGS1, VvGOGAT1 and VvGDH1 genes in leaves, thereby improving leaf nitrogen metabolism. In addition, the nitrogen application with 300kg·hm-2 (N2) among all the treatments significantly promoted the accumulation of nitrogen in leaves during the late growth period. At the same time, it promoted the increase of leaf area and net photosynthetic rate, and improved the fruit quality. © 2019 Journal of Fruit Science  相似文献   

4.
Soil managment in a ‘Bramley’s Seedling’ orchard, established in a system of herbicide treated tree rows and mown grass alleys, was changed to provide three treatments: complete grass cover, overall herbicide and a continuation of the existing system. Differential rates of N fertilizer (nil, 62.5 kg ha-1) were applied to each soil management regime. In comparison with herbicide strips, complete grass was intensely competitive, particularly with nil application of N fertilizer, reducing tree growth and yield and greatly decreasing leaf N. Leaves from trees in complete grass (nil N) plots contained higher concentrations of P, K and B but lower ones of Ca, Mn and Cu. Compared with the change from herbicide strip to complete grass management, effects of changing to overall herbicide were smaller. There were slight increases in leaf N concentration but no increases in tree growth or fruit yield. Leaf Mn concentration was increased in overall herbicide. Although application of N fertilizer to grass plots increased leaf N concentration by 0.4% and the three-year girth increment, yield was less than that of trees in herbicide strips. Nitrogen fertilizer applied to herbicide strips or overall herbicide plots slightly increased leaf N content but there was no effect on yield or girth increase. Applying N fertilizer to complete grass plots reduced the concentration of P, K and B in leaves but increased leaf Ca, Mn and Cu.  相似文献   

5.
Summary

The content of ammonium, nitrate and potassium was varied in the macronutrient solutions intended for formation of adventitious shoots from petiole expiants of Senecio × hybridus. The other components of the macronutrients were according to Murashige and Skoog (1962). The largest number of expiants which formed shoots was obtained when the nitrogen concentration in the Murashige-Skoog solution was lowered from 60 to 30 mM and the potassium concentration from 20 to 15 mM. Addition of 1.0 μM TIBA to the medium as well as the standard addition of 4.44 μM BAP and 28.5 μM IAA favoured shoot formation. Even growth in darkness for two weeks immediately after expiant excision increased shoot number. The nitrogen content in the tissue decreased as the nitrogen concentration in the medium decreased, although an increased concentration in the medium from 60 to 75 mM did not increase the nitrogen content in the tissue. When the potassium concentration was changed from 20 to 15 mM, in a medium with 30 mM nitrogen, the nitrogen concentration in the tissue increased. On the other hand, when using a medium with 60 mM nitrogen, the potassium concentration (30 and 20 mM) did not affect the nitrogen content of the tissue.  相似文献   

6.
SUMMARY

“Colour spots” (CS) in pepper fruit is a physiological disorder characteristic of some sweet pepper cultivars. The symptoms are yellowish spots on the outer surface of affected fruits. We investigated the effects of shading and nitrogen supply on the susceptibility of three sweet pepper cvs (Maor, Lady Bell and 899) to CS. The most susceptible was ‘Maor’. The incidence of CS was promoted by high N and shading. The fruits of all cultivars had lower nitrogen concentrations than the leaves but there were no significant differences in fruit N content between Maor and the CS-insensitive cultivars. The CS-affected areas of the pericarp tissue had higher calcium concentrations than unaffected tissue. Differences in magnesium or potassium concentrations in these spots were less pronounced. Scanning electron microscopy revealed that the affected pericarp cells contained crystals, presumably of calcium oxalate. Only in ‘Maor’ fruits was the oxalate concentration elevated by approximately nine-fold when the nitrogen supply to shaded plants was increased. We suggest that in the fruits of the sensitive cultivar, oxalic acid production is enhanced under high-nitrogen + shading conditions and causes the CS damage, possibly be chelating intracellular calcium.  相似文献   

7.
Experiments conducted over 2 years evaluated photoperiod and nitrogen conditioning of ‘Albion’ strawberry (Fragaria x ananassa Duch.) plants for off-season field production in New Jersey, USA. Plants were conditioned the first year with natural days (ND, natural daylength) or long days (LD, natural daylength supplemented with 24 h incandescent radiation) for one week followed by 100 or 800 ppm N for 4 weeks under ND or LD. The second year, plants were conditioned with ND or LD for 1 week followed by 1 to 6 weeks of 100 or 800 ppm nitrogen (N) under ND or LD. After conditioning, plants were established in plasticulture. Ripe fruit were harvested from August through October both years. LD conditioning enhanced precocity by approximately 9 days in both studies. Productivity was also enhanced by conditioning with LD or elevated N. Plants grown on silver or white mulch were more productive than those grown on black mulch in the first study, but not the second.  相似文献   

8.
Pruning in late summer was compared with winter pruning on mature 23-year-old spur pruned trees of Cox’s Orange Pippin on M.2 rootstock. Two nitrogen treatments were superimposed, namely a standard dressing of 126 units N (sulphate of ammonia) applied in March as compared with 288 units N (nitrate of soda) applied in mid-August at the time of summer pruning. Summer pruning reduced trunk girth increment, advanced blossom development, increased the amount of red colour on the fruits and drastically reduced the incidence of bitter pit in stored fruit. The treatments did not affect cropping. Nitrogen treatments had no overall effect upon the incidence of bitter pit, but in the first season, when bitter pit was most prevalent, high levels of N applied in August reduced the amount, a similar trend being recorded the following year.  相似文献   

9.
The β-amyloid protein (Aβ) has long been considered to associate with Alzheimers disease (AD). In addition, groups of evidence show that the soluble intracellular Aβ plays an important role in the disease development. The mitochondrial dysfunction induced by Aβ accumulation is a main pathologic process in early stage of AD. Matured Aβ is imported into the mitochondria through an unclear route. Once inside the mitochondria, Aβ is able to interact with a number of targets, including amyloid-binding alcohol dehydrogenase (ABAD) and cyclophilin D (CypD), which is a component of the mitochondrial permeability transition pore. Interference with the normal functions of these proteins results in mitochondrial injury, such as energy dyshomeostasis, production of reactive oxygen species, membrane permeability alteration and so on. This review explores the Aβ generation and location in mitochondria. The mitochondrial injury induced by the interaction between Aβ and its targets are also discussed.  相似文献   

10.
AIM:To investigate the role of NF-κB in pentetrazole-induced repeated seizure in developing rats with the inhibitor of NF-κB pyrrolidine dithiocarbamate (PDTC). METHODS:10-day-old Wistar rats (n=72) were prepared for epilepsy model and divided into three groups at random: the PTZ group, the PDTC+PTZ group and the control group. The behavioral changes, the cells morphology and neurons counts in hippocampus, the expression of NF-κB, BrdU (5-bromo, 2-deoxyuridine) immunoreactive cells in hippocampus and the mossy fiber sprouting were observed.RESULTS:(1) The NF-κB expressed in PTZ group was significantly higher than that in PDTC+PTZ group and control group (P<0.01). (2) The dentate gyrus granule cell count in PTZ group was significantly higher than that in control group (P<0.05). In PDTC+PTZ group cell counts in CA1, CA3 and hilar region were significantly lower than those in PTZ group (P<0.05). (3) The BrdU-immunoreactive cells counts in dentate gyrus in PTZ group and PDTC+PTZ group were significantly higher than those in control group (P<0.01), but in PDTC+PTZ group BrdU-immunoreactive cell count was significantly lower than that in PTZ group (P<0.01). Correlate analyzes between NF-κB expression and BrdU-immunoreactive cell counts/granule cell counts showed positive correlation (P<0.01). (4) The mossy fiber sprouting in both PTZ and PDTC+PTZ group was observed. However, the degrees of sprouting showed no significant differences between two groups. CONCLUSION:NF-κB plays a crucial role in epilepsy of developing rats. It encourages neurogenesis and protects neurons in hippocampus, but has no significant effect on mossy fiber sprouting.  相似文献   

11.
Banana is one of the main fruit crops and important food crops in the world, and it is also an important economic fruit in southern China. China is the border area of the origin of modern bananas, and one of the secondary origin centers as well. China has a history of banana cultivation for more than 2000 years and is the second largest country in banana production and consumption. Banana producing areas in China are mainly concentrated in Guangdong, Guangxi, Hainan, Yunnan, Fujian and Taiwan, with a small amount of cultivation in the south of Sichuan, Guizhou and Tibet. Most cultivated bananas are evolved from two wild species, Musa acuminate and Musa balbisiana, and their interspecific hybridization. The genome of Musa acuminata is called“genome A”, while the genome of Musa balbisiana is called“genome B”. According to the classification value of characteristics, banana cultivars can be divided into genotypes such as AA, AAA, AB, AAB, ABB, AAAA, AAAB, AABB, BB and BBB. Bananas cultivated in China are simply divided into four categories: Cavendish (AAA), Pisang Awak (ABB), Silk (AAB) and Dajiao (ABB). Cavendish banana is planted mostly in China (more than 80%), followed by Pisang Awak (more than 10%). Notably, in China, few people plant and consume Plantain (AAB), which is an important staple food in some area. Banana breeding mainly includes introduction (like Brazil and Williams banana), vegetative line selection (like GCTCV bananas), artificial mutation breeding (like Jiali banana), cross breeding (like Fenza No. 1 and Zhongjiao No. 9 banana), chromosome ploidy breeding, transgenic breeding and gene editing breeding. The introduction method is simple and direct. Our group took the lead in establishing the National Banana Germplasm Resource Garden in 1989. In the future, we should introduce not only high-quality varieties, but also multifunctional and diverse banana varieties to enrich China’s banana market. After introduction, people often get better lines that adapt to Chinese geographical and climatic conditions and planting habits, and then popularize them. Mutation breeding is easy, but the ideal excellent lines can only be obtained through a large number of screening and evaluation. The female flowers of some bananas, like Dajiao and Pisang Awak, have strong fertility, so they are often used as female parents to cross with wild bananas or cultivated varieties with certain fertility. Although sexual hybridization of banana needs a long period and is easy to fail, this method can often create new germplasm with diverse genetic background and relatively controllable traits, which is the most potential and promising method in traditional banana breeding at present. In recent years, researchers in China have created many new hybrid banana germplasm, and it can be predicted that a large number of new hybrid banana varieties will emerge in China in the near future. Banana transgenic and gene editing breeding have strong pertinence. China has made good achievements in the fields of banana transgenic and gene editing. However, as in many other parts of the world, these methods cannot be applied to business at present. At last, other breeding methods like somatic hybridization, rapid breeding and molecular-assisted breeding are rarely used at present. Banana Fusarium wilt and other diseases seriously threaten banana industry in China. At the same time, frequent typhoons and floods, severe frost and poor soil in the main banana producing areas in China also limit the further development of banana industry. Breeding new banana varieties with high yield, high quality and high stress resistance and adaptability is the key to break the bottleneck of banana industry development in China, and it is also a challenge for banana breeders in China. In addition, it is also an important direction to cultivate bananas with high nutrition and health care function, which are suitable for industrial processing or feed. During the last decades, China has made great achievements in banana breeding, but there are still many problems. First of all, banana biodiversity is relatively lacking, with few wild banana resources. Moreover, the careful evaluation of banana germplasm resources is not enough, limiting the utilization of them. Secondly, the main banana varieties in China were bred by introduction and mutation breeding, and only a few were bred by hybridization or other means. Moreover, due to many reasons, there is a lack of varieties with good comprehensive characteristics. Finally, it is difficult to study genes in banana through the forward or reverse genetic means, limiting the molecular research on banana. In the future, we should: (1) Continue to strengthen the collection, evaluation and utilization of global banana germplasm resources, and especially promote banana cross breeding vigorously; (2) Pay attention to the basic research on banana, dig out the key genes related to important economic traits, and analyze their regulatory networks, so as to lay the foundation for creating new banana varieties without transgene through gene editing technology in the future; (3) Continuously develop and upgrade new breeding techniques, promote the integration of various means, and breed efficiently and scientificly; (4) Breed new varieties that are resistant to various diseases and have good comprehensive properties, so as to win the banana defense war. In a word, we have summarized the research results of banana breeding in China in recent years, discussed the methods of banana breeding, the direction of new variety breeding and the main problems, in order to provide reference for banana breeding in China. © 2023 Journal of Fruit Science. All rights reserved.  相似文献   

12.
Increasing fertiliser use in agricultural landscapes is likely to threaten the viability of remnant native vegetation in many parts of the world. Australia’s prime grain production landscapes have nutrient poor soils, which formerly supported semi-arid woodland. The ecological function and capacity for regeneration of these remnants may be particularly susceptible to nutrient enrichment. The key sources of nutrients are wind and water deposition from crop fertilisation, and manure and feed from sheep. We hypothesised that these sources would result in unequal deposition of nutrients within and among remnant vegetation patches. We surveyed soil nutrients (Total N, Available P and K, C:N ratio, and soil pH) in the edges and interiors of 60 remnant woodland patches of various sizes, and in adjacent cultivated paddocks. Nutrient load was negatively correlated with remnant size and patterns were particularly strong for available P. Small remnant patches (<3 ha) were accumulation zones for nutrients, with levels comparable or higher than within crop lands. The patterns are consistent with the hypothesis that small remnants are strongly enriched as a result of being used for livestock shelter. In larger remnants, the primary cause of enrichment is consistent with edge accumulation of nutrients due to wind and water movement. In large patches, remnant edges, particularly the windward edge, were elevated compared to interiors of large patches. In these semi-arid crop lands, current trends in intensification of cropping and a shift away from livestock may reduce the input of nutrients to small patches but increase the nutrient threat to larger remnants.  相似文献   

13.
Five pruning treatments were compared on Cox’s Orange Pippin on M.II rootstock, viz.

1. Open-centre tree, established-spur pruned

2. Open-centre tree, renewal-pruned

3. Delayed open-centre tree, established-spur pruned

4. Delayed open-centre tree, renewal-pruned

5. Regulated-pruned tree.

At 15 years, secondary pruning treatments were begun and carried on for a further 7-year period, the trees being pruned by the same methods but either annually or in alternate years. Differences in growth and cropping between trees pruned to open-centre and delayed open-centre shapes were small, but open-centre trees cropped more heavily than did delayed open-centre trees when renewal-pruned, probably on account of their greater branch spread. The method used in pruning the laterals had an effect upon cropping during the first 10 years. At the end of the trial there was no effect of either primary or secondary treatments upon trunk girth, neither was there a significant difference in girth increment between the secondary treatments. Almost the same amount of wood was removed from trees pruned in alternate years as from those pruned annually, but a greater proportion of old to new wood was removed from trees pruned in alternate years. Pruning in alternate years increased the cropping of established-spur pruned trees but not with regulated or renewal-pruned trees. There was no consistently adverse effect upon fruit size but, when a year of heavy setting followed a winter when the trees were left unpruned, fruit size was reduced and early fruit thinning would have been necessary to lessen the proportion of fruit in the two smallest size grades. With this variety fruit colour was unaffected by pruning in alternate years.  相似文献   

14.
The expansion of the Shanghai metropolitan region has caused a substantial amount of farmland to become urbanized. Most farmers have lost their land and have been relocated from villages to new collective settlements, resulting in dramatic changes in the landscape pattern. This study explores the effects of this transformation on the spatiotemporal dynamics of plant diversity. We randomly sampled 22 plots comprising 294 subplots within two crossed transects that pass through 5 traditional villages and 17 new settlements. The results show that resettlement has exerted significant effects on plant species diversity, both temporally and spatially. Temporally, the Gleason index (GI) of total species over time could be ordered as 1990s > 2000s > 1980s, while Shannon’s diversity index (SHDI) was ordered as 2000s > 1990s > 1980s. Spatially, the GI of total species decreased from the urban center to the exurbs or from the inside to the outside of the built-up areas. SHDI was highest in suburbs or ecotones. Furthermore, the GI of total species had significant correlations with those of indigenous species, exotic species, and planted species (r > 0.90, p < 0.01) as well as with the region and location of settlement (r < −0.48, p < 0.01). Both indigenous and exotic species had significant positive correlations with total species richness at 0.01 levels. Generally, compared with traditional settlements, new settlements displayed greater richness and diversity of plant species, primarily because of the exotic species present in new settlements. The farmers’ socio-economic status was found to be the primary cause of differences in species richness. To protect indigenous and wild species, it is necessary to take into account local knowledge in villages to encourage Chinese farmers to participate actively in community greening. A bridge should be built between traditional villages and modern settlements and between the past and future for farmers.  相似文献   

15.
Summary

The intensity of watercore in ‘Orin’ apples (Malus domestica Borkh.) from the outer canopy increased from early-July to mid-August, followed by a decrease through late-October, while no watercore was detected in inner canopy fruit during the same period. Seasonal changes in sorbitol content in each cellular compartment paralleled the development of watercore. Significantly higher sorbitol, fructose and glucose contents in the vacuoles of cells in outer canopy fruit than in inner canopy fruit suggest that active metabolism and uptake of sorbitol might occur in watercored apples in mid-August. The permeability of sorbitol across the tonoplast was significantly higher in outer than in inner canopy fruit after mid-August, whereas no difference was observed between bearing position for the other sugars or for the plasma membrane. These data suggest that elevated sorbitol levels in the intercellular spaces might result from active apoplastic unloading and not from an inhibition of metabolism and/or an increase in leakage from cells.  相似文献   

16.
Cities continue to grow worldwide, and the highly modified urban landscape becomes an inhospitable environment for many species because the natural vegetation cover is commonly fragmented, and the remnants are often isolated. Protected Areas (PAs) located surrounding or within urban areas may not achieve their goal of protecting local or regional biodiversity. Thus, an urban ecological network is essential to support their PAs. Thus, this study aimed at assessing the PAs connectivity in an urban landscape in Brazil and understanding whether urban forest fragments can support an urban ecological network. Besides spatial models based on functional connectivity and graph theory, we used participatory techniques to design the resistance surface and the least-cost paths (LCPs) for Atlantic Forest birds. The results showed critical paths (LCPs), important areas for restoration programs for improving PAs connectivity, and essential forest fragments for conservation and restoration. Although the landscape has a forest structure with 1873 forest fragments and 516 links through which the LCPs were structured, most forest fragments and LCPs cannot provide the necessary support for the PAs connectivity. The current ecological network is dependent on forest fragments neighboring (outside PAs) and the flux dispersions occurred mainly in the peri-urban areas. Riparian zones and anthropic grasslands also showed importance for the PAs connectivity. We identified only 28 forest fragments spatially connected, presenting several sizes, and located near large forest areas, relevant PAs, and riparian zones. Six of these forest fragments, smaller than ten hectares and strategically located in the urban matrix, were indicated for restoration actions. The current low connectivity among PAs brings the importance of native vegetation restoration in the riparian zone and anthropic grassland and the importance of the periurban areas to promote biodiversity connectivity in the urban landscape.  相似文献   

17.
Summary

It had been established that photoperiodic conditions influence morphogenesis in Rhododendron catawbiense ‘Album’ (Ericaceae). Plants developed from cuttings obtained by in vitro culture were grown in a greenhouse for one or two years, under different photoperiodic treatments. Under long days, the upper buds followed a rhythmic development. Under short days, the inhibition of the growth of the distal buds allowed the development of shoots from the plant base. When plants were placed under long days after six weeks under short days, the distal buds recovered their capacity to form a new growth unit. To find a method to characterize growth potential of vegetative buds, measurements of their mineral content were made. A relationship between the changes in manganese level of the distal buds and their growth potential during the formation of the vegetative system has been established. Under short-day conditions, manganese increased to reach more than 500 mg kg-1 dry matter in several weeks. Under long days, the manganese level in the upper buds gradually decreased before burst. These results may not provide an explanation for the role of manganese in relation to the buds physiological activity. On the other hand, manganese measurements may be a useful test to estimate growth potential in Rhododendron buds.  相似文献   

18.
It is reasonable to assume that there is a relationship between the spatial distribution of forest fuels and fire hazards. Therefore, if fire risk is to be included into numerical forest planning, the spatial distribution of risky and non-risky forest stands should be taken into account. The present study combines a stand-level fire risk model and landscape level optimization to solve forest planning problems in which the fire risk plays an important role. The key point of the method was to calculate forest level fire resistance metrics from stand level indices and use these metrics as objective variables in numerical optimization. This study shows that maximizing different landscape metrics produces very different landscape configurations with respect to the spatial arrangement of resistant and risky stands. The landscapes obtained by maximizing different metrics were tested with a fire spread simulator. These tests suggested that the mean fire resistance of the landscape, which is a non-spatial metric, is the most important factor affecting the burned area. However, spatial landscape metrics that decrease the continuity of fire resistance in the landscape can significantly improve the fire resistance of the landscape when used as additional objective variables.  相似文献   

19.
Summary

Mature green mango fruit (Mangifera indica L. ‘Kensington Pride’) were stored at 0, 5, 10, 15 or 20°C for 1, 3, 7, 14, 21 or 28 d to induce different levels of chilling injury (CI) and to elucidate its relationship with aroma volatile production. The fruit were removed from storage and allowed to ripen at 22 ± 1°C and CI index was assessed on fully ripe fruit. Aroma volatile compounds were estimated from the pulp of fully ripe fruit. CI index significantly increased as the storage temperature was lowered and the storage period was extended, particularly in the fruit stored at 0, 5 or 10°C. CI symptoms did not develop on fruit stored at 15 or 20°C. Fifty-six aroma volatile compounds were identified from mango fruit pulp using headspace solid phase microextraction (SPME) technique with gas chromatography (GC-FID) and GC combined with mass spectrometry (GC-MS). Among the 56 aroma volatile compounds, 25 were quantified using GC, which included monoterpenes (±-pinene, ²-pinene, myrcene, 2-carene, ±-phellandrene, 3-carene, ±-terpinene, limonene, ocimine, ³-terpinene, ±-terpinolene, and a-terpineol), sesquiterpenes (±-copaene, ±-gurjunene, trans-carophyllene, aromadendrane, ±-humulene, alloaromadendrane, ³-gurjunene, and ledene), hydrocarbon (p-cymene), esters (methyl octanoate and ethyl caprylate), aldehyde (decanal), and norisoprenoid (²-ionone). A significant reduction in total aroma volatiles, monoterpenes, sesquiterpenes, hydrocarbon, esters, aldehyde, and norisoprenoid production were observed in fruit stored at 0, 5, 10 or 15°C compared with fruit stored at 20°C. The degree of reduction in aroma volatile compounds depended on the severity of CI, induced with different storage temperatures and storage periods. In conclusion lower temperature storage induced CI in mango fruit and adversely affected the aroma volatiles production.  相似文献   

20.

Mitteilungen

Patentierung in der Pflanzenzüchtung  相似文献   

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