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1.
Salinity is a major form of land degradation worldwide, with seasonal or temporary waterlogging often being an associated
issue. Acacia
ampliceps is a highly salt-tolerant small tree, naturally-occurring in north-western Australia, which produces abundant biomass with
potential for fuelwood and fodder. We investigated the extent of variation amongst provenances and families of A. ampliceps for seedling response to salt and waterlogging. Seven-week old seedlings from 27 families (seven provenances, grouped into
two regions), were treated in sand-filled pots in a glasshouse with either mixed salt (S) solutions (150 mol m−3 for 14 days, 300 mol m−3 for 33 days), waterlogging (W) or combined salt (S) and waterlogging (SW). Only 3% of seedlings died, mostly from the combined
salt × waterlogging treatment. Seedlings from the Kimberley region had significantly greater height and shoot biomass than
those from the Pilbara. Within these regions, Wave Hill (seedlot 14631) and Halls Creek (15738) provenances had the best growth.
Height growth was reduced similarly for S- and W-treated plants, whereas that of SW-treated plants was reduced much more.
Salt and waterlogging caused shoot dry weight reduction at harvest of 41 and 46%, respectively, with a slight interaction
between salt and waterlogging; SW treated plants were most affected. Generally there were relatively small differences in
the growth response of provenances and families to salt, but larger (often highly significant) variation in response to waterlogging.
Genotypic variation for shoot and phyllode water content and phyllode number in response to salt and waterlogging was generally
small. The good agreement found at the provenance level between seedling growth in this experiment and growth of young trees
on saline land in a trial in Pakistan suggests that glasshouse screening may be a useful means for selecting potential provenances
for field evaluation. 相似文献
2.
Julian Perez Sanford Eigenbrode Luko Hilje Robert Tripepi María Elena Aguilar Francisco Mesén 《Journal of pest science》2010,83(2):95-104
In order to determine their effects on growth and mortality of instar II Hypsipyla grandella (Zeller), larvae were fed with leaf disks taken from shoots of susceptible species (Cedrela odorata L. and Swietenia
macrophylla King) scions grafted onto resistant ones (Khaya senegalensis Desr. A. Juss and Toona ciliata M. Roem.), from their reciprocal grafts, and from both intact and autografted plants. In addition, crude leaf extracts from
the susceptible and resistant plants, as well as from C. odorata grafted onto T. ciliata plants, were tested on C. odorata leaf disks. Mortality was evaluated 2, 10, and 25 days after starting the bioassay. Leaf area consumed and weight gain per
larva were assessed 2 days after starting bioassay. Time to reach pupation, pupal weight and length 1 day after pupation,
and time to adult stage and appearance of wings were determined at the end of the bioassay. Plant species significantly affected
mortality (P ≤ 0.04) throughout the test. Eighty to 100% of larvae fed leaf disks from intact T. ciliata and its autograft, or C. odorata onto T. ciliata and its reciprocal graft died in the first 2 days of evaluation. All other factors measured, except pupal weight and length,
were also affected (P ≤ 0.01) by the leaf disks. Intact resistant plants and reciprocal grafted plants reduced leaf consumption and caused larval
weight loss. Larvae fed on K. senegalensis grafted onto S. macrophylla extended by 8 days the time to pupa and to adult stages and induced abnormal wing formation compared to larvae fed intact
leaves of C. odorata. Crude extracts from resistant plants equally affected larval survival and performance compared to crude extract from C. odorata grafted onto T. ciliata plants, and these extracts were more detrimental to larvae than those from susceptible species. This study demonstrated that
grafting borer-susceptible species on resistant rootstocks can affect the survival and performance of instar II H. grandella larvae. 相似文献
3.
A total of 55 Botrytis cinerea isolates collected from Pinus radiata and Eucalyptus globulus plants cultivated in nurseries located in the Bio‐Bio Region, Chile, as well as isolates collected from native plants such as Rubus spp and Aristotelia chilensis located near the nurseries were genetically characterized. All isolates carried the Bc‐hch2 allele, thus belonging to genetic Group II, which is now referred to as B. cinerea. Genotyping based on the presence of transposons Boty and Flipper showed differences between isolates related to the plant host. Thus, transposa isolates (containing both transposons) were detected in P. radiata and E. globulus, while vacuma isolates (containing neither transposon) were detected in all plants except E. globulus. Notably, boty isolates (containing just the Boty transposon) were detected at high frequencies in all plant hosts. Analyses to detect mutations involved in resistance to fungicides such as benzimidazoles (BZ), dicarboximides and QoIs also showed differences in the studied isolates. Isolates collected from E. globulus were shown to carry mutations for all tree fungicides, while those collected from P. radiata presented mutations involved in resistance to BZ only. Isolates collected from native plant hosts did not carry any of the mutations analysed. 相似文献
4.
Penicillium adametzii significantly inhibited the growth of Heterobasidium annosum sensu stricto on 2% potato dextrose agar after 10 days at 20–25°C. Chloroform extracts from P. adametzii culture filtrate and from culture grown on rice often decreased the dry weight of Armillaria colony and diameter of Heterobasidion colony in vitro. The effect depended on species and isolate of Armillaria, Heterobasidion and P. adametzii and concentration of the extract. Higher concentration of chloroform extract increased the dry weight of stems and roots of Pinus sylvestris plants inoculated with either of two isolates of Armillaria ostoyae and one isolate of Armillaria gallica. Lower concentrations of chloroform extract increased the dry weight of stems and roots of P. sylvestris inoculated with another isolate of A. gallica. Culture filtrate of P. adametzii decreased the length of necrosis on P. sylvestris stem inoculated with either of two of four isolates of H. annosum s.s., but if applied 1 month before inoculation, it increased the length of necrosis caused by another H. annosum s.s. isolate. Twenty fractions from the P. adametzii chloroform extract were separated by thin layer chromatography. Carboxylic acids, flavonoids and glycosides were detected in chloroform extract of P. adametzii by high performance liquid chromatography/mass spectrometer analysis. This is the first report of interactions between P. adametzii and either Armillaria or Heterobasidion with P. sylvestris. 相似文献
5.
Crataeva magna (Lour.) DC (synonym C. nurvala) is a high-value Indian medicinal tree. The multiple uses of C. magna have resulted in its over-exploitation. Erratic seed germination combined with destructive harvesting and habitat destruction
in the form of deforestation has added to the enormity of the problem. Therefore, the need for conservation of this plant
is vital. Development of an efficient micropropagation protocol will play a significant role in meeting the requirement of
quality planting material for commercial cultivation thereby conserving the species in its natural habitat. In the present
study, shoot multiplication was achieved by culturing single node segments derived from a field grown tree on Murashige and
Skoog’s (MS) medium supplemented with 2.66 μM N6-benzyladenine, 1.39 μM Kinetin (Kn), 0.57 μM indole-3-acetic acid (IAA),
3% sucrose and 0.2% gelrite. 96% rooting was achieved within 22 days by culturing the in vitro formed shoots on half strength
MS medium with 11.42 μM IAA, 9.8 μM indole-3-butyric acid, 0.46 μM Kn and 198.25 μM phloroglucinol. Following a simple hardening
procedure involving sequential transfer of plants to a greenhouse, polyhouse, and shade net, the tissue-cultured plants were
transferred to the field where the survival rate was 100%. To this date 500 plants have been produced. Inter simple sequence
repeat analysis has confirmed genetic uniformity of the tissue-cultured plants. 相似文献
6.
S. M. S. Huda M. Sujauddin S. Shafinat M. S. Uddin 《林业研究》2007,18(4):279-282
A study was conducted to test the influence of different inorganic fertilizers (phosphorous and potassium) on the nodulation and growth of Dalbergia sissoo grown in the nursery. Before seeds sowing, different combinations of P, K fertilizers were incorporated with the nutrient-deficient natural forest soils, and then amended with cowdung (soil: cowdung = 3:1). Nodulation status (nodule number, shape, fresh weight, dry weight and color) in the roots and the plant growth parameters (length of shoot and root, collar diameter, fresh and dry weight of shoot and root) were recorded 60 days after seeds sowing. Nodulation status and growth of the plants varied significantly (P〈0.05) in the soils amended with fertilizers in comparison to the control. The highest nodule number (62), fresh (0.50 g) and dry (0.07 g) weights were recorded with the dose of PK at the rate of 160 kg/hm2. Nodule shape and color also varied widely in different treatments. In case of plant growth parameters, shoot and root length, collar diameter, fresh and dry weight of the plants took on a significant difference (P〈0.05) among various combination of fertilizers. From the study, it is revealed that PK at the rate of 160 kg/hm^2 fertilizer with soil and cowdung mixture (soil: eowdung = 3:1) is recommended for optimum growth and nodule formation of D. sissoo in degraded soils at a nursery level. 相似文献
7.
We conducted a greenhouse experiment to investigate the role of seed source in growth and symbiotic nitrogen fixation of black locust (Robinia pseudoacacia L). Seeds from different sources were planted in the same environmental conditions and inoculated with a suspension of mixed Rhizobium. We used the modified 15 N isotope dilution method to estimate biological nitrogen fixation of Robinia trees. Different Robinia seed sources differed significantly in terms of tissue dry weight (50.6 80.1 g), total N (1.31-2.16 g) and proportion of nitrogen derived from the atmosphere ( 0-51%). A higher nitrogen fixation rate of Robinia trees was associated with higher dry weight. Moreover, the leaves of Robinia proved to adequately represent the nitrogen fixation capacity of entire plants. Our results confirmed that assessment of seed sources is a useful way to improve the nitrogen fixation capacity and therefore the growth rate of Robinia. 相似文献
8.
Information is lacking on the potential of leguminous fodder trees such as Leucaena leucocephala as a feed resource to supplement the native forages in traditional grazing management systems in the tropics. Two studies
were conducted (1) to assess traditional fodder banks’ forage nutritive potential on animal production, and (2) to investigate
the effect of Leucaena leucocephala leaf meal (LLM) supplementation on growth of steers grazing standing hay basal forages in the dry season. The traditional
forages had low nutritive values indicated by low mean crude protein (CP) of 23 g kg−1 dry matter (DM), and high fibre contents of 717, 546 and 153 g kg−1 DM for neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL), respectively. The forages
were poorly degraded in sacco and had low metabolisable energy (ME) (4.2–4.6 MJ kg−1 DM). Mean washing losses A, slowly degradable DM fraction, B, potential degradability, (A+B) and mean 48 h DM degradability
(DMD) of grazing land forages were 70, 471, 541 and 326 g kg−1 DM, respectively. In the supplementation study, 16 growing steers (160.8±0.24 kg) were randomly allocated into four groups,
in a completely randomized design. Four LLM treatment diets (T1, T2, T3 and T4), with four levels: 0, 0.4, 0.6 and 0.8 kg
DM for control, low, medium and high LLM levels, respectively, were randomly allocated to the animals in the four groups for
70 days (d). LLM supplementation (p<0.05) improved mean weight gain from −0.30 to 0.26 kg steer−1 d−1, for T1 and T4, respectively. Steers on T4 gained (p<0.05) more weight compared to the animals in T1 and T2, though there was no (p>0.05) difference in weight gains between animals on T3 and T4 (0.14 vs. 0.26 kg steer−1 d−1, respectively). Standing hay basal forages alone could not sustain animal productivity during dry seasons unless corrected
for protein. Higher levels of LLM supplementation prevented weight losses and improved the performance of grazing steers,
a management practice thought appropriate to low income pastoralists in semiarid western Tanzania. 相似文献
9.
Rupali Mehta Vikas Sharma Anil Sood Madhu Sharma Ram Kumar Sharma 《European Journal of Forest Research》2011,130(5):729-736
Bambusa nutans Wall., is an evergreen, perennial, and multipurpose bamboo having strong culms, which are largely used for construction,
scaffolding, craft purposes, pulp, and paper industry. Multiple shoots from nodal segments (3–4 cm) of young branches of mature
culms were established in Murashige and Skoog (1962) (MS) medium supplemented with various concentrations of 6-benzylaminopurine (BAP) (1.0–6.0 mg l−1) or in combination with α-naphthaleneacetic acid (NAA) (0.5–1.0 mg l−1) or kinetin (Kn) (1.0–2.0 mg l−1). February–March and December were found to be the best seasons for culture establishments. Maximum shoots were achieved
on MS medium fortified with BAP (2.0 mg l−1). Embryogenic callus (slightly greenish compact, globular, and slow growing) was initiated from the base of severed sprouted
buds in 2–3 subsequent subcultures on MS medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) (5.0 mg l−1) under dark incubations. Maturation and germination of well-organized somatic embryos was achieved on MS medium containing
BAP and 2,4-D (1.0 mg l−1 each) with 20.0 mg l−1 ascorbic acid. Full-strength MS medium supplemented with 2% glucose favored further development of proliferated somatic embryos
into plantlets. Genetic variations of field-established B. nutans plants regenerated through tissue cultures were assessed by amplified fragment length polymorphism (AFLP) analysis using
6 primer combinations. Four hundred and seven scorable fragments were amplified, of which 402 (98.8%) have recorded conservation
at various morphogenetic stages leading to plantlets regeneration, therefore, revealed a high level of genetic stability. 相似文献
10.
Nursery practice using microbial inoculants was performed to find out the efficacy of the inoculants on seed germination and
seedling growth of sissoo (Dalbergia sissoo Roxb.). Microbial inoculants or effective microorganisms (EM) are a mixture of many different beneficial microorganisms in
a solution. The seedlings were grown in a mixture of sandy soil and cowdung (3:1) kept in polybags with pouring EM solution
at different concentrations (0.1%, 0.5%, 1%, 2%, 5% and 10%) before and after a week of sowing the seeds. Seed germination
rate and growth parameters of seedlings were measured, such as, shoot and root length, vigor index, fresh and dry weight of
shoot and root and total biomass increment. The nodulation status influenced by EM was also observed along with the measurement
of pigment contents in leaves. The highest germination rate (69%) was observed in 2% EM treatment, followed by 67% and 65%
in 1% and 5% EM. The highest shoot length (33.2 cm) was in 2% EM, whereas highest root length (26.3 cm) was in 1% EM. Both
fresh and dry weights from shoot and root, were maximum (4.16 g and 1.57 g; 2.12 g and 0.83 g respectively) in 2% EM and were
significantly (p ≤ 0.05) different from control. Vigor index was highest (4071) in 2% EM, which was significantly (p ≤ 0.05) different from control. Total dry weight increment was highest in 2% EM treatment, followed by 1% and 5% concentrations
of EM. Nodulation number was higher at very low (0.1%) concentration of EM solution but it normally decreased with the increase
of EM concentrations. The contents of chlorophyll a, chlorophyll b and carotenoid were highest (60.11, 17.05 and 42.48 mg·L−1 respectively) in 2% EM treatment and lowest (39.35, 13.55 and 27.29 mg·L−1 respectively) in control treatment. Therefore, low concentration of EM (up to 2%) can be used for getting maximum seed germination
rate and seedling development of Dalbergia sissoo Roxb. 相似文献
11.
The use of peat as a growing media in forestry nurseries is decreasing due to high costs and environmental considerations.
Furthermore, diverse waste products are being used as organic amendments in certain soils before afforestation. In this study,
combinations of both of these resources are considered and seven different materials were used to make mixtures of growing
media used for maritime pine tree production in a forestry nursery. Pine bark, Sphagnum peat and paper mill sludge were mixed with sewage sludge, sewage activated sludge, municipal solid waste with activated composted
sludge and inorganic fertilizer to fill containers where pine seeds were sown. Germination was monitored 30–50 days after
sowing. Needle samples from each treatment were taken and physical parameters (height, stem diameter, aerial dry weight, main
root dry weight, total dry weight) were measured along with several morphological attributes. Foliar nutrient content was
also determined (N, P, K, Ca, Mg, Fe, Cu, Mn and Zn). The highest values for germination percentage were obtained for 75%
pine bark + fertilizer and for sewage sludge treatments. Seedlings grown in paper mill sludge + activated sewage sludge + peat
and in paper mill sludge + activated sewage sludge + pine bark mixtures presented the best physical parameter values. Municipal
solid waste and composted sludge were the most useful amendments for morphological attributes. After linking morphological
indexes and foliar nutrient content, the best Dickson Quality Index values correspond with higher values of N, Ca, Mg, Cu
and Zn and lower values of P, K, Fe and Mn.
Resumen El uso de turba en viveros forestales como sustrato de cultivo está decreciendo debido a su elevado coste y consideraciones medioambientales. Por otro lado, distintos residuos están siendo utilizados como enmiendas orgánicas sobre ciertos suelos previa reforestación. En este estudio, se considera una combinación de ambos factores y siete diferentes materiales fueron usados para hacer mezclas de sustrato de cultivo para la producción de pino marítimo en un vivero forestal. Corteza de pino, turba de esfagno y residuo de pasta de papel fueron mezclados con lodo de depuradora, lodo activado, residuos sólidos urbanos + lodo compostado y fertilizante inorgánico y utilizados para rellenar bandejas donde fue realizada la siembra. La germinación fue monitorizada 30–50 días después de la siembra. Se tomaron muestras de acículas de cada tratamiento y se analizaron parámetros físicos (altura, diámetro del tallo, peso seco parte aérea, peso seco de la raíz principal, peso seco total) además de distintos atributos morfológicos. El contenido foliar en nutrientes también se determinó (N, P, K, Ca, Mg, Fe, Cu, Mn and Zn). Los valores más elevados del porcentaje de germinación se obtuvieron para las mezclas: 75% corteza de pino + fertilizante y las enmiendas con lodo. El crecimiento de las plántulas presentó los mejores valores de los parámetro físicos para: residuo de pasta de papel + lodo activado + turba y para residuo pasta de papel + lodo activado + corteza de pino. La mezcla de residuos sólidos urbanos + lodo compostado proporcionó los mejores valores en relación a los atributos morfológicos. Relacionando los índices morfológicos con el contenido foliar en nutrientes se vió que los mejores valores para el Indice de Calidad de Dickson correspondieron con los valores más altos de N, Ca, Mg, Cu y Zn y los más bajos de P, K, Fe and Mn en el tejido foliar.相似文献
12.
The aphidophagous ladybird beetle, Hippodamia variegata (Goeze), is an important predator in many agricultural ecosystems. However, information on the influence of the prey’s host
plant species on its life history characteristics is still absent in the literature. Therefore, five host plant species of
Aphis gossypii Glover, viz. Cucumis sativus L., Cucurbita pepo var. medullosa L., Cucurbita moschata var. melonaeformis Poiret, Cucumis melo var. cantalupensis L. and Lagenaria siceraria var. gourda Standl., were selected to study the influence of the prey’s host plant species on the development, survival, reproduction
and life table parameters of H. variegata in the laboratory at 25°C. The results showed that all of A. gossypii from five host plant species used were acceptable for the growth, development and reproduction of H. variegata. However, the suitability of aphids from various host plants was different for this ladybird beetle. The complete pre-imaginal
development was longest (14.51 ± 0.17 days) when reared with aphids on C. melo var. cantalupensis and shortest (12.60 ± 0.11 days) on L. siceraria var. gourda. Total immature survival from egg to adult was highest (58.97%) on L. siceraria var. gourda and lowest (44.06%) on C. melo var. cantalupensis. Based on the intrinsic rate of increase as an index of suitability of prey host plant species on the population increase
of H. variegata, the suitability in decreasing order was: L. siceraria var. gourda > C. moschata var. melonaeformis > C. pepo var. medullosa > C. melo var. cantalupensis > C. sativus. This study offered opportunities for better understanding the tritrophic interactions of the plant–aphid–predator relationship. 相似文献
13.
《Scandinavian Journal of Forest Research》2012,27(4):312-319
Grey mould (Botrytis cinerea Pers.: Fr.) is the most common economically important fungal disease in Swedish forest nurseries. In tests in a growth room, foliage of predisposed (preinoculation incubation at 35°C for 4 days) Scots pine (Pinus sylvestris L.) seedlings was sprayed with suspensions containing Mycostop®, Binab® TF.WP or GlioMix® at concentrations of 0.5, 1 or 0.5 g l?1, respectively, and/or conidia of B. cinerea (106 spores ml?1). Binab and GlioMix reduced grey mould in needles by 94 and 92%, respectively, and were as effective as the fungicide Euparen® M 50 WG, while Mycostop reduced disease by 51%. In one trial in a forest nursery, Mycostop, Binab and GlioMix, each applied two and four times during the growing season, suppressed spontaneous B. cinerea infections in needles of first year container-grown P. sylvestris seedlings by 16–57%, and were as effective as recommended fungicidal sprays. It was concluded that biological control has potential to effectively suppress grey mould in seedlings in forest nurseries. 相似文献
14.
In May 2019, Aucuba japonica var. variegata, known as an evergreen shrub, was found to have multiple leaf spots in Nanjing City, Jiangsu Province, China. A fungus was isolated from the margins of the lesions and one isolate JS-RL3 was selected for identification and pathogenicity tests. The morphological characteristics of the fungus were similar to Botrytis cinerea. Phylogenetic analysis using concatenated sequences of ITS and G3PDH also showed that isolate JS-RL3 clustered with strains of B. cinerea, a relationship supported by a 100% bootstrap value. This report is the first of B. cinerea causing leaf spots on A. japonica var. variegata. 相似文献
15.
The effects of the arbuscular mycorrhizal (AM) fungus Glomus mosseae on plant growth, leaf solutes and root absorption area of trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings were studied in potted culture under water stress conditions. Inoculation with G. mosseae increased plant height, stem diameter, leaf area, shoot dry weight, root dry weight and plant dry weight, when the soil water
content was 20%, 16% and 12%. AM inoculation also promoted the active and total absorption area of root system and absorption
of phosphorus from the rhizosphere, enhanced the content of soluble sugar in leaves and roots, and reduced proline content
in leaves. AM seedings had higher plant water use efficiency and higher drought tolerance than non-AM seedlings. Effects of
G. mosseae inoculation on trifoliate orange seedlings under 20% and 16% soil water content were more significant than under 12% soil
water content. AM infection was severely restrained by 12% soil water content. Thus, effects of AM fungi on plants were probably
positively related to the extent of root colonization by AM fungi. The mechanism of AM fungi in enhancing drought resistance
of host plants ascribed to greater osmotic adjustment and greater absorption area of root system by AM colonization.
__________
Translated from Journal of Plant Physiology and Molecular Biology, 2005, 30(5): 583–588 [译自: 植物生理与分子生物学报, 2005, 30(5): 583–588] 相似文献
16.
The nature of damage of sweetpotato whitefly, Bemisia tabaci (Gennadius) B biotype was investigated at the vegetative stage on eggplant (Solanum melongena L., family Solanasae, variety Baiyu) under laboratory conditions (temperature 25 ± 1°C, RH 70 ± 10% and photoperiod 12 h
L:12 h D). The investigations were carried out after completing one generation of whitefly on the basis of morphology, physiology
and anatomy of eggplant leaf. Significant differences were observed on three morphological parameters—leaf area, leaf fresh
weight, and leaf dry weight. The reduction percentages of these three parameters were 26.6, 21.8 and 19.27%, respectively.
Significant differences were also observed on two physiological parameters—chlorophyll content and rate of photosynthesis.
The reduction percentages of these two parameters were 9.7 and 65.9%, respectively. There were no damaged tissue observed
in the epidermis and mesophyll, but there were some damage tissue observed in the vascular bundle of infested leaf. There
were no damaged vascular bundles observed in the control leaves. The non-damaged vascular bundles contained both xylem and
phloem; while some damaged vascular bundles contained either xylem or phloem. Associated with the non-damaged vascular bundles
on whitefly infested leaves were two settled whitefly nymphs apparently deriving nutrition from phloem sap. After one generation
of whitefly infestation, the number of damaged and non-damaged vascular bundles of eggplant leaf was significantly different. 相似文献
17.
Fikret Demirci Murat Muştu M. Bora Kaydan Selma Ülgentürk 《Journal of pest science》2011,84(3):337-342
Citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is one of the main pests on citrus trees. Biological control of the pest is based on
the release of hymenopterous parasitoids and coccinellid predators at present. The effectiveness of entomopathogen fungus
Isaria farinosa (Holmsk.) Fries ([Sordariomycetes: Hypocreales] (Syn: Paecilomyces farinosus), as an alternative biological control agent on citrus mealybug, was investigated using four different inoculum densities
and different relative humidities (RH). The entomopathogen caused 89.39% mortality in ovisacs, 84.07% mortality in second
larval stage, 84.53% mortality in adult females, and 78.71% mortality in first larval stage at 95% RH and at 1 × 108 conidia ml−1 inoculum concentration. Percent mortalities were between 50 and 60 in ovisac, first and second larval stage at 95% RH and
at 1 × 107 conidia ml−1. Percent mortality was decreased parallel to the decrease in humidity level and inoculum densities; however, the fungus caused
significant infection in 70% and 80% RH. These results demonstrated that the effectiveness of the entomopathogen is promising
for biocontrol of citrus mealybug. 相似文献
18.
Yvens E.M. Cordeiro Hugo A. Pinheiro Benedito G. dos Santos Filho Sofia S. Corrêa Joo R.R. e Silva Moacyr B. Dias-Filho 《Forest Ecology and Management》2009,258(7):1449-1455
Young mahogany (Swietenia macrophylla King) plants were grown under either well-watered (pre-dawn leaf water potential, Ψpd, ca. −0.40 MPa) or drought (Ψpd, ca. −3.52 MPa) conditions to examine some physiological strategies that allow the maintenance of leaf turgor. In well-watered plants, stomatal conductance (gs) was nearly constant (440 mmol m−2 s−1) between 7:00 and 13:00 h. This was accomplished by significant increases in transpiration (E) and apparent total hydraulic conductance (KT), in which averages were higher at 13:00 h. From 13:00 to 17:00 h, gs, E, and KT decreased sharply, reaching their lower values at 17:00 h. In these plants, significant increases in height (116%), stem diameter (50%) and leaf area (200%) were registered over the experimental period (20 days). Analyses of linear regression between gs or E and leaf-to-air vapor pressure deficit (Δw) were not significant. In water-stressed plants, gs and E were higher at 7:00 h and lower from 9:00 to 17:00 h, while KT was higher in early morning (7:00 h) and in late afternoon (17:00 h) than between 9:00 and 15:00 h. Moreover, both gs and E decreased potentially (P < 0.001) with the diurnal increases on Δw. Drought also decreased leaf and leaflet numbers and reduced total leaf area, but had no effect on stem height and diameter. Leaf proline was higher (ca. 400%, between 13:00 and 15:00 h) in water-stressed plants, suggesting osmotic adjustment under drought. Twelve hours after resumption of irrigation, Ψpd was similar (P > 0.05) between well-watered and drought-stressed plants, suggesting an ability of plants to recover turgor after stress cessation. Altogether, our data support the hypothesis that young mahogany plants have the ability to satisfactorily tolerate or postpone drought. 相似文献
19.
Kavita Arora Meena Sharma Jyoti Srivastava S. A. Ranade A. K. Sharma 《Agroforestry Systems》2010,78(1):53-63
An efficient in vitro process for rapid clonal propagation of a 40-year-old tree of Azadirachta indica employing nodal stem segments was developed. Season of collection and maturity of explants showed direct influence on bud-break.
Nodal stem segments collected during the month of April gave best response. Maximum bud-break (78.6–81%) was obtained when
middle order nodes (3rd or 4th node from apex) were taken. Amongst different cytokinins used, 6-benzylaminopurine (BAP) at
the concentration of 1.11 μM was found most effective in inducing multiple shoots, whereas inorganic and organic constituents
of the medium influenced growth and general condition of proliferating shoots. On an average 3.1 shoots per explant were regenerated
in modified Murashige and Skoog medium supplemented with 1.11 μM BAP, 1.43 μM indole-3-acetic acid (IAA) and 81.43 μM adenine
hemisulphate. Isolated shoots were rooted in presence of 2.46 μM indole-3-butryic acid (IBA). Root induction took place in
8–10 days with 100% rooting. The in vitro-raised plantlets were successfully transplanted in potted soil and finally grown
under field conditions with 100% survival. The genetic fidelity of such in vitro-raised field-grown plants was ascertained
by random amplified polymorphic DNA (RAPD) markers. Furthermore, the azadirachtin content of in vitro-cloned plants was found
comparable to the mother tree proving their chemical stability also. The protocol developed holds good for in vitro cloning
of mature elite neem trees. 相似文献
20.
Two field trials were conducted under rainfed conditions at El-Obeid Research Farm and Eldemokeya Forest Reserve, North Kordofan
State during the growing seasons 2004/2005 and 2005/2006. The objective was to investigate the effect of Acacia senegal on the performance and yield of groundnut (Arachis hypogea), sesame (Sesamum indicum) and roselle (Hibiscus sabdariffa) in an agroforestry system. The two trials consisted of seven treatments: three represented the intercropping of groundnut,
sesame and roselle with A. senegal, three without trees and one represented A. senegal alone. Data were recorded on soil physical and chemical properties, soil moisture content, crops fresh weight (kg/ha), dry
weight (kg/ha), gum yield (g/picking) and crop yield (kg/ha). The trees at El-Obeid yielded no gum, whereas those at Eldemokeya
were 15 years old and were tapped as part of the total harvest in the agroforestry plots. Land equivalent ratios (LER) and
simple financial analyses of gross surpluses were used to evaluate the productivity of the different treatments. Fresh weight
of groundnut, sesame and roselle was significantly different (P < .0.05) at both sites. Higher fresh weights were found under the intercropping system than the sole cropping system. This
could be attributed to a shading effect that limits fruit production of the field crops more than vegetative growth. Dry weights
were significantly greater for sesame and roselle in both sites, while that of groundnuts was not significantly different.
In both sites, intercropping reduced the yield of sesame by 6 and 11% in the first season and 37 and 39% in the second season.
The reduction in roselle yield was 19 and 28% in the first season and 15 and 8% in the second season. Yield reduction in groundnut
was 35 and 17% in the first season and 35 and 11% in the second season. The combined analysis indicated that intercropping
reduced groundnut yield by 26%, sesame by 21% and roselle by 20%. All the treatments gave LER of more than one—indicating
the superiority of growing the field crops in intercropping over the sole cropping systems. The highest LER of (1.71) was
obtained when roselle was intercropped with A. senegal, while the lowest LER (1.48) was obtained when groundnuts were intercropped with A. senegal. All the treatments gave positive net revenues, the highest being for intercropped roselle (438 SDG/ha). The intercropping
of sesame gave the second highest net revenue (387 SDG/ha), while the sole roselle gave the lowest net revenue (97 SDG/ha). 相似文献