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1.

• Introduction   

Atmospheric deposition is an important input of major nutrients into forest ecosystems. The long-term goal of this work was to apply stable isotope methodology to assess atmospheric nutrient deposition in forest systems.  相似文献   

2.
Hard red winter wheat was treated at 0 (untreated control), 25, 50, 75, and 100% of the label rate of the insecticide Storicide II ® , which is chlorpyrifos-methyl and deltamethrin applied at label rates of 3 and 0.5 ppm, respectively. Paired male and female Rhyzopertha dominica F., the lesser grain borer, were exposed at 27°C and 60% RH on wheat treated at each of the five rates above for 2, 4, 8, 16, or 32 h, and then transferred to untreated wheat and held for 1 week at the same environmental conditions. After this 1-week holding period, the parental adults were removed, mortality was assessed, and the wheat was then held for 7 weeks at the same environmental conditions to determine progeny production. As the concentration and exposure interval increased, mortality of both sexes approached 100%, but at the intermediate concentration–time combinations male mortality was greater than female mortality. Progeny production also decreased with increasing concentration of Storicide II® as the exposure time increased, with non-linear patterns of decrease at the lower concentrations and time combinations and linear decline at the higher levels of concentration and time. Results seem to indicate greater susceptibility of males to Storicide II®, and also show delayed parental mortality from the insecticide exposure and sub-lethal effects of reduced progeny production.  相似文献   

3.
Growth and physiological performance of multipurpose tree species can be severely constrained by low phosphorus (P) availability in highly weathered soils. Limitations to plant growth are accentuated by seasonal dry periods. The overall objective of this study was to examine P fertilization and irrigation effects on survival, growth, biomass partitioning, foliar nutrients, intrinsic water-use efficiency (WUE) indexed by δ13C, Rhizobium nodulation, and carbohydrate content as an indicator of resprouting potential, of mimosa (Albizia julibrissin Durz.), a N2-fixing tree species being tested for browse in agroforestry practices in south-central USA. In a field experiment carried out during two growing seasons near Booneville, Arkansas, USA, mimosa had a strong growth response to irrigation. The trial was arranged in a split plot design with three replications with irrigation as main plot treatment and P as sub-plot treatment. Mean total plant aboveground biomass at the end of the second growing season was 9.8 and 44.1 g plant−1 for the rainfed treatment without and with 300 mm of irrigation water, respectively. Placed P fertilization increased mean total aboveground biomass from 19 g plant−1 for the 0-P treatment to 69 g plant−1 for the treatment with 90 kg P ha−1 year−1. Similarly, irrigation consistently increased stem basal diameter, total height, survival, root, stem, foliar and total aboveground biomass, and number of nodules per plant. Phosphorus fertilization increased basal diameter, and root and stem biomass in both irrigation treatments, survival and nodulation in the rainfed treatment, and foliar and total aboveground biomass in the rainfed +300 mm irrigation treatment. There was a decrease of foliar δ13C suggesting that WUE decreased with P fertilization. In a pot experiment, seedlings were subjected to a factorial combination of two irrigation treatments and six P levels in a randomized complete block design. Irrigation increased basal diameter, root, stem, foliar and total biomass, leaf area and nodulation, whereas P fertilization (i.e., levels from 0 to 3.68 g P kg−1 soil) had similar effect in all the above variables except foliar biomass. Foliar P concentration to obtain 90% of the maximum total plant biomass (critical level) was estimated at 0.157%. Total nonstructural and water soluble carbohydrate, and starch concentrations increased non-linearly with irrigation and P addition suggesting impaired re-growth potential after defoliation of seedlings with reduced water supply and at low soil P availability. Results of this study indicated strong limitations for growth and regrowth potential of mimosa on a highly weathered soil with very low P availability and seasonal water content shortages. Placed (i.e., near the plant base) application of P appeared to be a good strategy to fertilize perennial woody plants.  相似文献   

4.
In the laboratory, a commercial neem-based insecticide—Nimbecidine®—was evaluated as a potential pest management tool for the terrestrial snail, Monacha obstructa (Pfeiffer, 1842) (Hygromiidae). Effects of different concentrations of the botanical insecticide on food consumption and egg hatchability of the terrestrial snail were studied. Generally, food consumption of immature and adult snails decreased as the concentrations of Nimbecidine® increased. At the highest concentration (10 ml/l), the snails avoided contacting with food completely. The food intake of immature individuals was significantly (p < 0.05) more affected by the Nimbecidine® treatment (at 1.25 ml/l) than that of adults. LC50 of Nimbecidine® for the treated eggs was 2.18 ml/l, and eggs failed to hatch at concentration of 10 ml/l. Nimbecidine® showed sufficient biological activity against the food consumption and eggs viability of M. obstructa, thus the preparation has a potential to protect field crops from this pest snails.  相似文献   

5.
–  • Carbon isotope composition (δ13C) is a complex trait involved in acclimation, adaptive processes and related to water use efficiency (WUE) and/or productivity.  相似文献   

6.
The red flour beetle, Tribolium castaneum (Herbst), is one of the most serious secondary pests that feeds on a wide range of durable stored products including cereals, cereal products and other high value produce such as cocoa beans and dried fruits. Toxicity and protectant potential of Calneem® oil derived from the seeds of the neem tree Azadirachta indica A. Juss. towards T. castaneum were evaluated in stored wheat in the laboratory using contact toxicity, grain treatment, persistency, progeny emergence and repellency assays. Calneem® contains about 0.3% azadirachtin as its major active ingredient. The Calneem® was applied at six dosages (0.1, 0.2, 0.5, 1.0, 2.0 and 3.0% v/v). The oil was emulsified with water using 0.07% soap. All dosages of Calneem® oil were toxic and highly repellent to T. castaneum with an overall repellency in the range of 52–88%. The highest dosage of 3.0% of Calneem® oil tested killed at least 90% of the beetles within 72 h on grain, and 88% mortality was obtained on filter paper. T. castaneum mortality was dose dependent. The development of eggs to adults on cracked wheat was significantly (P < 0.05) inhibited by Calneem® oil treatments. The effectiveness of Calneem® oil was significantly reduced by the length of storage after application. The results obtained suggest good potential for the practical use of Calneem® oil as grain protectant for stored product pest control. The use of plant materials such as neem oil may be a safe, cost-effective method of grain preservation against pest infestation amongst low-resource poor farmers who store small amounts of grains.  相似文献   

7.
A series of experiments were conducted in which adults, pupae, and 4-week-old larvae of Tribolium castaneum (Herbst), the red flour beetle, were exposed separately on concrete arenas partially treated (14.4% of the total area) with the insecticide chlorfenapyr (Phantom®) at 1.1 g of active ingredient/m2. A flour food source (patch) was also provided in the untreated portions of the arenas. In the first trial, adult mortality averaged 60.0 ± 10.6%, but progeny production occurred in the provided food patches. Pupal mortality was only 8.3 ± 3.1%, indicating that when adult emergence occurred, those adults were able to escape exposure, and there was no difference in progeny production from that in untreated controls (P = 0.27). In the second trial, few larvae exposed in choice and no-choice arenas were able to emerge as normal adults. In a final trial, residual efficacy declined during a 3-week period, with larvae being more susceptible than adults. Results show mobility of life stage may be a determining factor when assessing susceptibility of T. castaneum to contact insecticides.  相似文献   

8.
Conjugation of δ-endotoxin from Bacillus thuringiensis with abamectin, a toxin of Streptomyces avermitilis, was carried out to form a new type of biocide, GCSC-BtA based on “Germany-China Scientific Cooperation” research, for the control of agricultural insect pests. The strategy for biochemical linkage was designed by conjugating an amino group in B.t. protoxin with a carboxyl group in carboxylated abamectin under the treatment of conjugator EDC [1-Ethyl-3-(3-dimethylaminopropyl carbodiimide Hydrochloride)]. The formation of B.t. protoxin was processed by solubilizing B.t. crystal in 25?mM dithiothreitol (DTT) at 37?°C for 2?h. The carboxylated abamectin was formed by carboxylating the NaH-activated abamectin with 10?mg/ml butyric anhydride at 111?°C in a water-circumfluent condensation device for 2?h. The conjugating reaction, consisting of 5?mg/ml B.t. protoxin, 10?mg/ml carboxylated abamectin and 19.17?mg/ml EDC, was successfully conducted at room temperature for 24?h. Significant differences were found between pure abamectin, carboxylated abamectin and the conjugated BtA by means of UV-photo absorptions recorded at wavelengths 354, 438, 518, 600?nm (P?<?0.01). LT50 of the conjugated GCSC-BtA to the 3rd instar larvae of Plutella xylostella (L.) (Lep., Plutellidae) was 35.27 μg a.i./ml, about 62?% and 76?% of that caused by the B.t. protoxin and the caxboxylated abamectin, respectively. The conjugated GCSC-BtA caused 87.14?% mortalities in larvae of P. xylostella, 93.75?% in adult Myzus persicae (Sulzer) (Hom., Aphididae) and 89.33?% in adult Phyllotreta vittata Fabricius (Col., Chrysomelidae) as compared to 48.33?% by the B.t. crystal only in P. xylostella. The symptoms caused by conjugated GCSC-BtA in the 3rd instar of P. xylostella were black color in the head part and white-yellow in the abdomen of dead larvae, which differed from the black color or the white-yellow all along the body caused by either the B.t. crystal or the abamectin, respectively. It was concluded that the conjugated GCSC-BtA biocide had a broader host spectrum and a faster killing speed than either the B.t. crystal or abamectin alone for the control of agricultural pests.  相似文献   

9.
Ethanol was produced from the hydrolysate collected as the water-soluble (WS) portion after hot-compressed water (HCW) treatment of Japanese beech. The process involved saccharification with β-xylosidase followed by isomerization with xylose isomerase and fermentation with Saccharomyces cerevisiae. Several process schemes were compared to investigate the effect of process integration of saccharification, isomerization, and fermentation. Higher ethanol yields were obtained for the processes that integrated isomerization and fermentation or saccharification and isomerization. Integration of isomerization and fermentation was effective in converting xylose into ethanol. Similarly, integration of saccharification and isomerization was effective in converting xylooligosaccharides into xylulose. It is presumed that the saccharification reaction toward xylose and the isomerization reaction toward xylulose were linked and therefore each reaction was enhanced.  相似文献   

10.
Enzymatic saccharifications of the hydrolysate collected as the water-soluble (WS) portion after hot-compressed water (HCW) treatment of Japanese beech with xylanase and β-xylosidase were performed to investigate the hydrolytic properties of these enzymes. The WS portions with different molecular weight distributions and initial concentrations of xylooligosaccharides were prepared as substrates, one of which contained mainly smaller xylooligosaccharides [degree of polymerization (DP) = 2 or 3], while the other contained larger xylooligosaccharides (DP ≥ 4). The highest xylose recovery was obtained from both of the WS portions treated with β-xylosidase rather than with xylanase. This suggests that β-xylosidase could have a higher activity than xylanase toward larger xylooligosaccharides (DP ≥ 4) as well as smaller xylooligosaccharides (DP = 2 or 3) recovered from HCW treatment. As a result, the use of β-xylosidase was found to be effective for saccharifi cation of the WS portion, even with a short reaction time for the HCW treatment.  相似文献   

11.
•  Introduction  The simulation of diameter distributions is the basis for predicting volume in the so-called diameter distribution models. Combined with volume, volume ratio and taper equations, these models allow the prediction of volume assortments according to user needs. The simulation of diameter distributions is also essential in initialising individual tree models. It is also a useful aid for planning harvesting operations.  相似文献   

12.
 The optimum conditions for β-thujaplicin production in a Cupressus lusitanica cell suspension culture were investigated. The conditions required for β-thujaplicin production were clearly different from the conditions for cell growth. The initial phosphate concentration and pH did not affect β-thujaplicin production. A total nitrogen source concentration higher than 3.2 mM suppressed production due to the presence of the ammonium ion. β-Thujaplicin production was observed at 95 mg/l without adding the ammonium ion to the medium. Strict control of major inorganic nutrients was not necessary to produce β-thujaplicin. This finding seems to be favorable for future automated production of β-thujaplicin in commercial cell culture plants.  相似文献   

13.
In this study, polyesters were prepared from sulfuric acid lignin (SAL) that was generated as a by-product during the production of bioethanol from lignocellulosic materials using ɛ-caprolactone (CL). Carboxylic groups were introduced into SAL by a hydrothermal reaction under alkali conditions. The acid form (-COOH) of the obtained polymer (HSAL) was dissolved into ɛ-caprolactone and the mixture was heated at 150°C for 12 h with ZnCl2 as a catalyst. The structure of the obtained polymer (PCL-HSAL) was proposed based on results of differential scanning calorimetric analysis, swelling tests, and dynamic mechanical thermal analysis. The hydroxyl group in HSAL participated in the ring-opening polymerization of CL. PCL-HSAL with a high HSAL content formed a three-dimensional network that did not dissolve in organic solvents and did not melt at high temperature. PCL-HSAL showed a high swelling property for a suitable ratio of CL to HSAL.  相似文献   

14.
Amplified fragment length polymorphism (AFLP) was used in genetic fingerprinting of 22 elite Chinese Populus deltoides and Populus × canadensis accessions. The results indicated that each of the nine AFLP primer pairs selected generated fingerprint profiles that were unique to each of the accessions. Therefore, each accession was definitively identified by any of the nine primer pairs. Furthermore, the inter-accession genetic relationships inferred based on 461 polymorphic fragments from the nine AFLP primer pairs were largely consistent with phylogenetic relationships based on morphologic traits. Bootstrap analysis showed that three AFLP primer pairs were required to obtain genetic similarity values with a maximum CV of 10% while 10 AFLP primer pairs could give a maximum CV of 5%. Thus, AFLP can readily be applied for a rapid and accurate evaluation of the degree of similarity between poplar cultivars. In this study, the number of AFLP fragments used was sufficient to establish a reliable estimate of genetic similarity among accessions, with a maximum CV of 5.12%. Therefore, the information on the genetic relationships among the poplar accessions generated in this study in connection with knowledge on agronomic traits may have an impact on poplar breeding and planting in China.  相似文献   

15.
Defence proteins are a kind of chemical defence compounds. They play a key role in plant restraining biotic and abiotic harm. To illuminate activities of some defense proteins associated with age or plant family of larch, the larch needles were collected from two different families of Korean larch, Larix olgensis and a hybrid larch, L. kaempferi × L. gmelinii, respectively, and then the activities of defence proteins in those were tested using a UV spectrophotometry. The results showed that the activities of protective enzymes at the16-/17- and 19-year-age groups were higher than those at the other age groups in the both larch species. While the activities of polyphenol oxidase (PPO) at the 16-/17-year-age group and phenylalanine ammonia-lyase (PAL) and protease inhibitors at the 19-year-age group were the highest among all age groups. Then, compared with L. olgensis, the hybrid larch had significant effects on the activities of protective enzymes. The effects of plant family on the activities of PAL and chymotrypsin inhibitor were significantly different, and then those on the activities of PPO were not significantly different. The effects of the two families in L. olgensis on the activities of trypsin inhibitor (TI) were significantly different, while those in the hybrid larch on the activities of TI were contrary. To conclusions showed that the different age and plant family significantly affected the activities of defence proteins in the needles of two larch species, and then enhanced the larch resistance to pests. These could play a key function in forestry tree genetic improvement and management in future.  相似文献   

16.
The effect of Thidiazuron （TDZ）, basal media and light quality on adventitious shoot regeneration from in vitro cultured stem of Populus albaxP berolinensis were determined to establish a high efficiency shoot regeneration system from stem explants of P. alba~P berolinensis. Stems ofPopulus alba~P berolinensis were collected from cultured shoots in vitro derived from dormancy buds of 3-year-old seedlings. The stem explants were cultured on MS medium containing 0.02-mg·L-1NAA （naphthaleneacetic acid）, and 0.1, 0.3, 0.5 and 1.0 mg·L-1 concentrations of TDZ to determine the effect of TDZ on shoot regeneration. Three basal media, i.e. MS, woody plant medium （WPM） and B5, were used to test their influences of different media on adventitious shoot regeneration. Green, red, blue and yellow plastic films in comparison with florescent light as control were used to observe their effects on shoot regeneration. The results showed that differ- ent concentrations of TDZ had an evident influence on shoot regeneration. Lower concentration of TDZ （0.1 mg·L-1） resulted in more ad- ventitious shoot regeneration and higher concentration of TDZ （〉0.1 mg·L-1） inhibited shoot regeneration. Among different media, MS medium exhibited a high efficiency for shoot regeneration, followed by WPM medium, while B5 medium inhibited shoot regeneration. Normal light and yellow light exhibited better effects on shoot regeneration, compared with other light.  相似文献   

17.
As part of a feasibility study of the commercialization potential of C. indicum nuts as Agroforestry Tree Products in Papua New Guinea, preliminary characterization studies have examined the tree-to-tree variation in morphological traits (nut and kernel mass and kernel:nut ratio), as well as nutritional (carbohydrate, fat, protein, sodium, vitamin E) and medicinal traits (anti-oxidant activity, anti-inflammatory activity and phenolic content) of kernels from 18 to 72 trees in a small number of different villages of Papua New Guinea (East New Britain Province). There was continuous variation in these traits indicating opportunities for multiple trait cultivar development targeted at food and pharmaceutical markets. Certain traits, for example anti-inflammatory activity, in which tree-to-tree variation was highly significant, present greater opportunities than others, such as saturated:unsaturated fatty acid ratio. This intraspecific variation was greater within populations than between populations. The data presented has allowed the development of a strategy to domesticate C. indicum for cultivation in homegardens and cocoa–coconut agroforests, using a participatory approach aimed at the production of agroforestry tree products (AFTPs) to empower small-holders and enhance their livelihoods and income.  相似文献   

18.
Interrelationships between self-thinning, biomass density, and plant form were mathematically modeled in relation to stand development in which self-thinning is either not occurring or is occurring. The relationship between biomass density and mean shoot mass is derived as a simple power function at the stage when self-thinning does not occur. When self-thinning occurs, constant biomass density is attained when the 3/2 power law of self-thinning applies and the allometric coefficient is assumed to be 1/3 in the allometry between mean plant height and aboveground mass. The applicability of this mathematical model and the allometric reformulations of the self-thinning exponent were tested using experimental data for dense populations of Chamaecyparis obtusa seedlings during the first 2 years of growth. On the basis of the results of the present model and experimental data, the dependence on competition of the mean height:diameter ratio, mean stem diameter, and leaf biomass density are discussed. As a result, the mean height:diameter ratio was almost asymptotically constant at the latter growth stage in the second-year seedlings, so that the 3/2 power law of self-thinning was held in the present analysis. However, the value of height:diameter ratio will become smaller in older stands, because tree height is considered to be asymptotic with respect to tree age due to hydraulic and other limits. Therefore, the present modeling implies that one of the reasons why the 3/2 power law from a geometric basis has been recently rejected depends on whether or not the height:diamter ratio is constant in older trees.  相似文献   

19.
The effects of nutritional treatments and the flowering promoter Paclobutrazol™ on tree growth and fertility were studied in unpedigreed seedling seed orchards (SSOs) of Eucalyptus camaldulensis and E. tereticornis at two locations in southern India. At Pudukkottai, a semi-arid site in Tamil Nadu State, five treatments were applied: (1) untreated control, (2) nitrogen (two doses of urea at 217 g N/tree), (3) nitrogen plus phosphorus (two doses of 312 g single superphosphate), potassium (two doses of 83 g muriate of potash) and trace elements (two doses of 10 g sodium borate and 25 g zinc sulphate), (4) pollarding trees at 4 m height with application of N, P, K and trace elements, (5) drenching with the flowering promoter Paclobutrazol (0.25 ml active ingredient per cm of stem girth) along with N, P, K and trace elements. At Panampalli, a higher-rainfall site in Kerala State, only treatments 1, 2 and 3 were applied. Four replicates of treatment plots sized 18 m × 18 m, with 22–32 trees per plot were set up in each orchard in randomized complete block designs. Untreated plots of E. camaldulensis and E. tereticornis at Pudukkottai displayed 12 and 21% fertile trees, respectively, in the first year of monitoring, while at Panampally the percentage of fertile trees in untreated E. camaldulensis plots was higher at 72%, and that of E. tereticornis similar at 23%. Both species attained greater stem diameter at breast height at age 9 years at the higher-rainfall location but there was no significant impact of fertilizer application on 9-year diameter at either site. Diameter was reduced by pollarding and Paclobutrazol application at Pudukkottai. Only Paclobutrazol produced a significant increase in fertility in both species for four successive years, increasing the percentage of fertile trees to 59 and 71%, respectively, for E. camaldulensis and E. tereticornis 1 year after application. The number of capsules produced per tree also increased significantly with Paclobutrazol application, although the difference was comparatively less by the fourth year. The number of capsules per umbel did not differ significantly between locations, whereas the germination rate varied between treatments although no consistent trends were observed.  相似文献   

20.

• Introduction   

Stem taper equations have been widely used for volume estimation to varied top diameter limits or for biomass calculations. However, their main drawback is that specific calibration is often necessary for each species or clone, and accounting for genetic and environmental effects is often a challenge.  相似文献   

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