Nursery Experiment Research Articles

Effects of Plantain (<i>Musa species</i>) as Shade on the Growth Performance of Cocoa Seedlings in the Nursery at Ibadan, Southwest, Nigeria

Nursery experiment was carried out at Ibadan, Nigeria between May 2004 and October 2005 to evaluate the use of plantain as a permanent cocoa nursery shade crop. Ibadan is located between latitude 07?10'N and longitude 03?52'E and lies at an altitude of about 122 metres above the sea level. The treatments consisted of six shade regimes provided by plantain spaced at 1.0, 1.5, 2.0, 2.5 and, 3.1 m apart, the control had no shade at all (open planted cocoa). Each treatment had one hundred cocoa seedlings planted in polythene bag filled with topsoil and laid out in a randomized complete block design (RCBD) in three replications. Data on vegetative growth of cocoa seedlings were taken on monthly basis, while plantain height, girth, number of leaves, bunch weight, number of fingers and market value of each treatment were evaluated. Light intensity under each of the treatment was taken using light meter. Result showed that cocoa seedlings under plantain shade planted at 1.0 m and 1.5 m apart were higher in height relative to control and other treatments considered, shade regimes provided by spacing at 3.1 × 3.1 m and 2.5 m × 2.5 m apart on the other hand produced higher values for stem diameter and leaf area respectively compared to other treatments, the least values were recorded under 1.0 m × 1.0 m apart. Seedlings under 2.5 m and 3.1 m spacing were significantly (p > 0.05) higher for these parameters than other treatments. Higher incidence of weed was also recorded from the control. Plantain bunch obtained from 2.5 m and 3.1 m apart was higher than other treatments in terms of weight, number of fingers and market value, while the control (no plantain shade) did not give any economic returns. Hence, plantain planted at spacing of 2.5 m or 3.1 m apart could be recommended to the cocoa farmers in Nigeria as nursery shade instead of conventional method of using bamboo and palm fronds yearly without any additional economic return.

Growth response of Casuarina equisetifolia Forst. rooted stem cuttings to Frankia in nursery and field conditions

Casuarina equisetifolia Forst. is a tree crop that provides fuel wood, land reclamation, dune stabilization, and scaffolding for construction, shelter belts, and pulp and paper production. C. equisetifolia fixes atmospheric nitrogen through a symbiotic relationship with Frankia, a soil bacterium of the actinobacteria group. The roots of C. equisetifolia produce root nodules where the bacteria fix atmospheric nitrogen, which is an essential nutrient for all plant metabolic activities. However, rooted stem cuttings of elite clones of C. equisetifolia by vegetative propagation is being planted by the farmers of Pondicherry as costeffective method. As the vegetative propagation method uses inert material (vermiculite) for rooting there is no chance for Frankia association. Therefore after planting of these stocks the farmers are applying 150 kg of di-ammonium phosphate (DAP)/acre/year. To overcome this fertilizer usage, the Frankia-inoculated rooted stem cuttings were propagated under nursery conditions and transplanted in the nutrient-deficient soils of Karaikal, Pondicherry (India), in this study. Under nursery experiments the growth and biomass of C. equisetifolia rooted stem cuttings inoculated with Frankia showed 3 times higher growth and biomass than uninoculated control. These stocks were transplanted and monitored for their growth and survival for 1 year in the nutrient-deficient farm land. The results showed that the rooted stem cuttings of C. equisetifolia significantly improved growth in height (8.8 m), stem girth (9.6 cm) and tissue nitrogen content (3.3 mg g-1) than uninoculated controls. The soil nutrient status was also improved due to inoculation of Frankia.

Performance of seedlings of tree borne oilseeds and their response to fertilization in problem soils

The aim of the present investigation was to screen the seedlings of tree borne oilseeds (TBOs)suitable for alkali and saline soils and to optimize their fertilizer requirement under different soilenvironments. A nursery experiment was conducted at Forest College and Research Institute,Mettupalayam with four TBOs viz., neem, pungarn, simaruba and jatropha on three soil types viz.,neutral, alkali and saline soils with four fertilizer levels (0:0:0, 100:75: I00, 200: 150:200 and 300:225:300mg N, ~20j and K.zO seedling:'). The soils were .sandy loam in texture with 195, 170 an? 165 kg haI of available N; 1J.6, 10.9 and 9.8 kg ha' of available P; 182,200 and 176 kg ha' of available K and0.48%,0.33% and 0.30 %organic carbon for neutral, alkali and saline soils respectively.The biometric observations viz., collar diameter, shoot, root and total dry matter production and root:shoot ratio were recorded at 180 days after sowing. The total dry matter production of neem, pungarn,simaruba andjatropha (13.49, 12.19, 11.20 and 17.29 g seedling:', respectively) in alkaii soil was 88.9,96.3, 75.0 and 64.9 per cent respectively as that of neutral soil. Application of 200: 150:200 mg N,P,Oj and Kp scculing' (N,P,K) excelled all other I.~vels for neern (15.37 g seedling:'), pungam(f 4.03 g seedling:') and simaruba (12.84 g seedling ') which has resulted in 40.0, 50.2 and 46.1 percent increase over control. With regard to jatropl:a, the highest total dry matter was recorded with 300:225:300 mg N,P,K seedling:' (19_04· g seedling:") which has registered an increase of39.2 percent over control.The total dry matter production of neem, pungam, sirnaruba andjatropha (10.89, 13.66,8.76 and 13.07g seed ling", respectively) in sal ine soi I was 7l. 7, J 07.9, 58.6 and 49. J per cent as that of neutral soi I.Neern, pungam and simaruba recorded the highest total dry matter production with 200: 150:200 mgN,P-K seedling:' (14.02,16.79, and 9.74 g seedling.", respectively) recording a percent increase of35. i, 70.1 and 21.9, respectively over control. In the case of jatropha, the highest total dry matter(16.33 g seedling") was recorded with 300:225:300 mg N,P,K seedling:' with an increase of74.7 percent over control.The present study suggests that pungam and neem were the best suited species for alkali and salinesoils followed by simaruba andjatropha. The performance of the crops was relatively better in alkalisoil than saline soil. The fertilizer requirement under neutral soil was 300:225:300 mg N, PoO- andK,O seedling:' for all the crops. Whereas for alkali and saline soils, the fertilizer requirerrierit forneem, pungam and simaruba was 200: 150:200 mg N,P,K seedling:" and for jatropha, the requirementwas 300:225:300 mg N,P,K seedling':'.

SEEDLING GROWTH PERFORMANCE OF FOUR Syzygium species IN THE SIMULATED LIGHT AND SOIL NUTRIENT ENVIRONMENTS OF A RAIN FOREST IN SRI LANKA

Seedlings of four species of Syzygium (S. firmum, S. makul, S. operculatum, S.rubicundutn) were investigated for differences in growth and survival after one and halfyears growth in a nursery experiment. All four species co-exist in the moist evergreen rainforest of South western Sri Lanka. S. firmum is a canopy tree on valleys to midslopes. S.rubicundum is considered a canopy tree of late-successional forest on hill mid slops. BothS. makul and S. operculatum arc sub canopy trees of late-successional forest alongstreamways of lower slopes and valleys.Seedlings of each species were grown within replicated light and soil nutrient treatmentsfound in the groundstorey forest environments. The light treatments exposed seedlings toi) full sun; ii) sunlight like that at the center of a 200 m2 forest opening. iii) sunlight likethat at the center of a 400 m2 canopy opening; iv) 50% shade of sunlight with qualitysimilar to the outside edge of a 400 m2 canopy opening on the shaded side; v) 20% ofsunlight with a quality similar to the inside edge of a 400 m2 canopy opening on theshaded side and vi) I% of sunlight with a quality and amount similar to the forestunderstorey. Within each light treatment seedlings were grown with additions ofphosphorus, potassium, magnesium, al\ three combined and a control with no additionalnutrients. At the end of one and half years seedlings were measured for net photosynthesis,height increment, leaf number and survival.Seedling survival for all species was low in the forest understorey treatment. Both survivaland seedling height were greatest in shelters simulating forest openings. Leaf productionwas highest in full sun and inside edge light treatments and all species had their greatestnet photosynthesis in the inside edge treatment. For nutrient treatments phosphoruspromoted greatest seedling growth in all species

Preplant 1,3-D treatments test well for perennial crop nurseries, but challenges remain

Preplant fumigation with methyl bromide commonly is used in open-field perennial crop nurseries in California for control of plant-parasitic nematodes, pathogens and weeds. Because this fumigant is being phased out, alternatives are needed to ensure the productivity of the perennial crop nursery industry as well as the ornamental, orchard and vineyard production systems that depend on clean planting stock. As part of the USDA Area-Wide Pest Management Program for Integrated Methyl Bromide Alternatives, several perennial crop nursery projects were conducted in California from 2007 to 2011 to test and demonstrate registered alternative fumigants and application techniques that maximize performance and minimize environmental impacts. The project was designed to evaluate shank application and soil surface sealing methods intended to reduce aboveground emission and improve soil performance of 1,3-dichloropropene, a leading methyl bromide alternative for nurseries. In these garden rose and tree nursery experiments, 1,3-dichloropropene treatments performed well regardless of application techniques. In this article, we highlight recent research and discuss the significance and remaining challenges for adoption of methyl bromide alternatives in this unique nursery stock production system.

Improving propagation methods of Ricinodendron heudelotti Baill. from cuttings

Ricinodendron heudelotii is a valuable multipurpose tree from Africa that is lacking an efficient and inexpensive vegetative propagation method. To improve multiplication, a series of nursery experiments were conducted to assess the effect of propagation media, plant growth regulators (NAA and IBA), accession source harvest timing, cutting type, and pre-treatment with honey. Maximum survival and rooting percentages of 90.2 and 93.7% respectively were achieved in all experiments. The maximum number of leaves and roots were respectively, 7.4 and 8.7; maximum root length was 15.6cm. Fine sand was superior to sawdust or fine sand:sawdust mixture. IBA, at 100μg/l was more effective than NAA for rooting and growth. Principal component analysis showed that, independent of the accession source, cuttings harvested from April to May were more suitable for propagation, giving the highest rates of rooting and growth. In contrast, variable results were achieved with apical cuttings (highest rooting), basal single-node leafy cuttings (highest number of leaves and length of root) and basal two-node leafy cuttings (highest number of roots). Cuttings were more successful when they were soaked in honey for 60min. After acclimatization, maximum survival rate of plants was 67.6%. This improved protocol can be incorporated into agro forestry system in which propagation of R. heudelotii is a component.

Evaluation of Density and Cage Design for the Nursery and Grow-Out of the Tropical AbaloneHaliotis asininaLinne 1758

The effect of stocking density and cage design on the growth, survival rate, and feed conversion ratio was evaluated for the nursery (11–15 mm in shell length) and juvenile grow-out (26–30 mm in shell length) of the tropical abalone Haliotis asinina. Abalone were fed Gracilaria sp. within a randomized 2 × 3 factorial experiment using 2 stocking densities (Tl (500 pieces/m2) and T2 (1,000 pieces/m2)) and 3 cages (D1, box; D2, mesh cage; D3, prefabricated multitier trays). In addition, 3 stocking densities (T1, 50 pieces/m ; T2, 100 pieces/m; T3, 200 pieces/m) were evaluated in the prefabricated multitier trays. We found that, in the nursery experiment, 4-mo-old tropical abalone juveniles reared for 90 d showed no significant differences in growth (shell length and body weight) and survival rates among the 3 nursery cages used (Tukey's post hoc test, P > 0.05). Feed conversion ratio, however, was lowest for the high-density treatment T1D3 (7.8 ± 0.76) and was significantly different from the low density treatment T1D1 (11.32 ± 1.2) and intermediate density treatment T1D2 (12.39 ± 1.12; t-test, P > 0.05). Conversely, at higher densities (T2), the same trend applied with abalone reared in multitier basket systems (T2D3), having the highest growth rates and survival rates (29.3 ± 0.07 mm average shell length (ASL) and 5.16 ± 0.52 g average body weight (ABW)), followed closely by those reared in mesh cages (T2D2) and boxes (T2D1). Feed conversion ratio was also lowest for T2D3 (7.56 ± 0.79) and was significantly lower than T2D1 and T2D2. Between treatments, however, abalone reared at lower densities (T1) had significantly higher growth and survival than those reared at higher densities (T2), regardless of the nursery cage used, indicating an inverse relationship between stocking density, growth, and survival. For the grow-out study, tropical abalone reared in multitier trays at low densities (T1) attained the highest growth in shell length and body weight (49.7 ± 0.11 mm ASL and 29.8 ± 2.6 g ABW, respectively) at 180 d of culture, which was significantly greater than those reared in the high-density treatment (T3) with significantly smaller shell length and body weight (43.8 ± 0.18 mm ASL and 21.2 ± 2.0 g ABW), but not significantly different than the intermediate density treatment. This trend started from day 60 of culture onward when analyzed using Duncan's multiple range test (P > 0.05). Survival rates were not significantly different among stocking density treatments, nor were feed conversion ratios. We recommend, for nursery rearing of abalone juveniles, using multitier trays (D3) or boxes (D1) at 500 pieces/m2 stocking density to attain a grow-out size of 26–30 mm in shell length in 90 days. A stocking density of 100 pieces/m2 is recommended to grow abalone in multitier trays to attain a cocktail size of 50 mm ASL and 30 g ABW in 180 d with survival rates between 85.6% and 83.1%.

Clonal variation in growth, arsenic and heavy metal uptakes of hybrid Eucalyptus clones in a Mediterranean environment

Variation in growth, arsenic and heavy metal uptakes by aboveground tissues (leaves, stems and branches) of 13 hybrid Eucalyptus clones selected for biomass production in a Mediterranean environment (E. camaldulensis × E. viminalis; E. camaldulesis × E. grandis; E. camaldulensis × E. globulus subsp. bicostata) was investigated on agricultural soils field-contaminated with arsenic (As), cadmium (Cd), chrome (Cr), lead (Pb), copper (Cu) and zinc (Zn) in an ex situ nursery experiment in central Italy. Large variation in growth and contaminant uptake amongst the tested clones was observed. All plants survived and 12 clones grew better than the control (E. camaldulensis). All clones accumulated the contaminants to which they were exposed: As, Cu, Pb and Zn concentrations were significantly higher in leaves than in stems and branches, supporting the potential for phytoremediation of these contaminants by Eucalyptus short rotation woody crops (SRWC). Significant positive correlations between the average contents of Cd–Pb, Cd–Cu, Cd–Zn, Pb–Cu, Pb–Zn and Cu–Zn in the aboveground tissues were detected. Clones revealed better phytoextraction performance than that of the control. Four promising clones for biomass production and phytoremediation were identified for prospective use in SRWC on contaminated soils in Mediterranean environments.

Effects of Fungicide Treatments for the Control of Epidemic and Exotic Calonectria Diseases in Italy.

The efficacy of 11 fungicides was evaluated for the control of Calonectria infections on bottlebrush (Callistemon "Masotti") and feijoa (Acca sellowiana), with special emphasis on Calonectria pauciramosa and C. morganii, which are the most destructive species in Italian ornamental nurseries. Three nursery experiments were performed with the selected fungicides in order to determine their ability to prevent leaf spot caused by C. morganii on bottlebrush and leaf spot and crown and root rot caused by C. pauciramosa on bottlebrush and feijoa. All fungicides were effective in reducing disease infections, except for cyproconazole, propamocarb + fosetyl-Al, and K phosphite that were the least effective in reducing C. morganii leaf spot. In contrast, K phosphite proved more effective in reducing crown and root rot caused by C. pauciramosa. Fungicides were also evaluated in growth-cabinet experiments for their ability to reduce incidence and severity of leaf spot on bottlebrush caused by the exotic pathogens C. pseudomexicana, C. tunisiana, C. polizzii, and C. mexicana. Copper hydroxide, fosetyl-Al, prochloraz, prochloraz + cyproconazole, and tebuconazole were always effective in reducing Calonectria leaf spot on bottlebrush. However, some differences in levels of control might be attributable to Calonectria isolate. Overall, this study clearly indicates that new fungicides can be employed for chemical management of Calonectria infections in ornamental nurseries.

Suppressive biomasses and antagonist bacteria for an eco-compatible control of Verticillium dahliae on nursery-grown olive plants

Two organic amendments (OMW-M1 and OMW-M2), based on olive mill wastes (OMWs) subjected to advanced processes of aerobic static storage or composting, were tested for their suppressive activity against Verticillium dahliae, the causal agent of olive Verticillium wilt. OMW- M1 and OMW-M2 drastically inhibited the pathogen growth in vitro and then were further tested in suppressive pot experiments. The amendments, mixed at 15 % (v/v) with a nursery standard plant-growth matrix, were tested alone or in combination with two biocontrol bacteria (Bacillus amylo- liquefaciens and Burkholderia cepacia) selected from sup- pressive soils. All mixtures were artificially contaminated with V. dahliae microsclerotia (MS), the density of which was periodically monitored by either a semi-selective med- ium or a specific real-time Polymerase Chain Reaction technique. In plant-less pot assays conducted in a growth chamber, OMW-M1 was the most effective amendment, reducing V. dahliae MS density by 100 % after 90 days with respect to the untreated control. In nursery experiments with pot-growing olive plants, OMW-M1, particularly when combined with the biocontrol bacteria, confirmed its strong suppressive activity reducing up to 100 % the density of V. dahliae MS in the rhizosphere behaving even better than a commercial biofungicide (Trichoderma asperellum TV1) used as a control. The best combined treatment also reduced plant mortality and increased root and shoot extension. It is concluded that organic amendments from stabilized olive mill by-products showed positive agronomic and phytosan- itary properties on pot-growing olive plants and, particularly when enriched with biocontrol agents, they are potentially suitable for use in sustainable agriculture.

Effect of Pre-Emergence Herbicides on Weed Control in Jatropha (Jatropha Curcas L.) Nursery

Nursery experiments were carried out to evaluate two different pre-emergence herbicides on germination, seedling growth and weed control efficiency of Jatropha nursery. Three days after sowing, pre-emergence herbicides viz. pendimethalin (30% EC) and fluchloralin (45% EC) were applied at different concentrations on the nursery bags using rose cane. Twenty days after application of herbicides, observations were made on germination percentage and 45 days after application of herbicides, parameters like number of predominant weeds (broad leaved, grasses and sedges), weed dry weight(g), weed control efficiency (%), germination (%), root length (cm), shoot length (cm) and dry matter production (g seedling-5) of Jatropha seedling in each treatment were recorded. The results revealed that the compatibility of application of pre-emergence herbicide of pendimethalin @ 0.05% - 0.10% can be used effectively to control broad leaved weeds, without impairing the germination and seedling growth of Jatropha curcas.

The effect of nursery measures on mycorrhizal colonisation of Scots pine and occurrence of soil mites

The aim of the study was to determine the influence of organic fertilization (treated sewage sludge with addition of bark or sawdust) and mulching (forest edaphon inoculation) on the vitality of Scots pine (Pinus sylvestris L.) seedlings and their mycorrhizal structure, as well as the occurrence of soil mites (Acari). Nursery experiments were carried out in 2005 to 2007. It was stated that the studied factors influenced seedling vigour, mycorrhizal colonization, soil properties and the occurrence of mites. Key words: Pinus sylvestris L., mycorrhiza, Acari, mulching, fertilization

Provenance variation in survival, growth and dry matter partitioning of Parkia biglobosa (Jacq.) R.Br. ex G.Don seedlings in response to water stress

The effects of drought stress on growth and dry matter partitioning of seven provenances of Parkia biglobosa were assessed in a nursery experiment. Three different water regimes were applied: soil high, medium and low water content (HWC, MWC and LWC) corresponding respectively to 100, 75 and 50 % of field capacity. A split-plot experimental design was applied with the provenance as main plot and the water regime as sub-plot, replicated three times. Each provenance was represented by 30 seedlings in each replication, corresponding to three test periods with ten seedlings each (6, 12 and 18 months after water stress started). There were significant interactions between provenance and water regime for survival rate and the relative growth rates of diameter and height. After 18 months, the dry matter mean was 20.00 ± 0.65 g for the HWC regime, 11.50 ± 2.90 g for the MWC regime while all plants in the LWC regime died. After 6 months, the accumulated water use efficiency (WUE) showed significant differences between water regimes, but not between provenances. Seedlings from the LWC regime showed higher WUE than those from the MWC regime. However, the HWC regime displayed the highest mean value of WUE. Despite differences between provenances, it was not possible to clearly separate them according to the geographical position or climatic parameters, based on the growth performance or both fresh to dry weight and shoot to root dry weight ratios.

The Use of Asian Ficus Species for Restoring Tropical Forest Ecosystems

Fig (Ficus spp.) trees have been promoted as framework species for tropical forest restoration throughout Asia, because they are considered to be keystone species. This article presents optimal propagation and planting techniques for six Asian dioecious Ficus species, which will enable their inclusion in forest restoration plantings across the Asia‐Pacific region: Ficus auriculata, F. fulva, F. hispida, F. oligodon, F. semicordata, and F. variegata. Nursery experiments compared the growth performance of propagating planting stock from seed and from leafy cuttings, whereas field experiments assessed the cost‐effectiveness and the relative performance of (1) direct seeding, (2) planting stock from seed, and (3) planting stock from cuttings. The most efficient method of producing Ficus spp. was from seed. Propagation from cuttings was much less successful. Seedlings produced from seed had the highest rates of growth and survival both in the nursery and in field trials. In field trials, use of planting stock from seed was also more cost‐effective than direct seeding and vegetative propagation. Establishment costs calculated on the basis of “per plant established” were $1.14 for seed, $6.95 for cutting, and $25.88 for direct seeding.

Regeneration pattern of four threatened tree species in Sudanian savannas of Burkina Faso

Research was carried out on four threatened tree species across north and south Sudanian phytogeographical zones in Burkina Faso. A quantitative inventory of regeneration populations was completed and sapling dynamics were monitored through surveys of survival and growth in permanent plots. Laboratory and nursery experiments were carried out to test germination and the performance of transplanted seedlings. Results revealed difficulties that saplings faced during their development. In natural stands of Sterculia setigera and Afzelia africana, saplings were rare or irregularly distributed. A greater number of individuals of Bombax costatum were observed, which was the only species with significant density variation between phytogeographical zones (p = 0.021). Size class showed irregular population structures. A high mortality between the first and second year, followed by a stabilization trend, was observed. The initial height of saplings was highly correlated to their survival rate. The rate of new sapling spontaneous recruitment was better in Bombax costatum and Boswellia dalzielii stands, but heir growth was unpredictable in all species. Most saplings grew from lignotubers and root suckers; however, the potential for sexual reproduction was good. Sterculia setigera and Bombax costatum seedlings showed potential for use in silviculture, as evidenced by the fact that both showed high post-transplantation rates of survival and growth.

Evaluation of the effect of chitin-rich residues on the chitinolytic activity of Trichoderma harzianum: In vitro and greenhouse nursery experiments

The chitin-rich residues obtained from several industries have numerous applications in diverse fields such as biotechnology, pharmacology, medicine and agriculture. In this study, three different chitin-rich residues were evaluated with regard to enhancement of the chitinolytic activity of the mycoparasitic fungus Trichoderma harzianum, used for biological control of Fusarium oxysporum in greenhouse nurseries. Chitosan (CHIT), shrimp shell powder (SSP) and mushroom wastes (MW) activated the expression of the T. harzianum genes encoding the NAGase and chitinase activities (exc1, exc2, chit42, chit33 and chit37), the highest in vitro activities of T. harzianum being seen with MW. Under greenhouse nursery conditions, the treatments involving amendment with these residues and with T. harzianum increased the NAGase activity (between 5- and 20-times higher than peat) and the chitinase activity (between 3- and 6-times higher than peat) of the growing media and maintained the shoot dry weight of plants infected with F. oxysporum. Moreover, the incorporation of these residues into the growing media enhanced the growth (first leaf length, stem length and shoot dry weight) of muskmelon seedlings. The use of these residues with T. harzianum as amendments of growing media enhanced the growth of muskmelon seedlings and decreased the weight loss due to the pathogen, giving an added-value to these residues and enhancing their management.

Growth Promotion and Bi-Control Approaches of Brown Root Rot Disease of Tea by Pseudomonas Aeruginosa (PM 105)

Pseudomonas aeruginosa (PM 105) isolated from tea (Camellia sinensis) plantation soil of Barak Valley, Assam, (India) showed biocontrol and growth promotion potential against the tea root pathogen Fomes lamoensis, infested one year old tea plants under nursery condition. In the in vitro antagonism study, PM 105 showed significant inhibition in all the three media (KB, NA and PDA) tested against the pathogen, both in spot and line inoculation. In the nursery experiment, tea plants treated with F. lamoensis alone showed 73% disease incidence, whereas in P. aeruginosa along with the pathogen showed reduced percentage of disease incidence (only 33.33%). An increase in number of new leaves (NNL), number of lateral branches (NLB), shoot height (SH) and root length (RL) was observed, following the application of the bacterial treatment. It was also observed the fresh weight of shoot (FWS), and root (FWR), dry weight of shoot (DWS), and root (DWR), chlorophyll a and b in P. aeruginosa treated plants, have also increased. The results indicate the biocontrol and plant growth promoting potentials of P. aeruginosa on tea.

Pre and Post-Emergence Damping-Off of <i>Chrysophyllum albidum</i> G. Don and C. delevoyi Dewild in Port Harcourt

A nursery experiment on pre- and post-emergence damping off ofChrysophyllum species was conducted in the Department of Forestry andWildlife Management in the University of Port Harcourt, Nigeria in 2010.The study assessed the fungi associated with seed and seedlings ofChrysophyllum albidum and C. delevoyi in the nursery. A sample of thirtyseeds each were collected randomly from the seed lot for both species andgerminated in trays using a completely randomized design with three replicates. The germinants were observed over a period of 28 days. Disease incidence, germination percentages and seedlings damaged were observed and data recorded respectively. The t-test was used to separate the means. Fusarium oxysponum, Aspergillus flavus and Trichoderma species were implicated as causal agents of damping off in the two species. The fungal pathogens strongly impacted on the mean percentage germination percentage of the species in the unsterilised/medium with 34% and 7.33% for C. albidum and C. delevoyi respectively. Similarly the mean seedling survivals for the species were 28% and 6% for C. albidum and C. delevoyi respectively. Chrysophyllum species are highly susceptible to fungal pathogens in the nursery.

Phenotypic plasticity to light of two congeneric trees from contrasting habitats: Brazilian Atlantic Forest versus cerrado (savanna)

The Brazilian Atlantic Forest is a typically multi-layer tropical forest, while cerrado (savanna) is a patchy habitat with different physiognomy. Despite these differences, both habitats have high light heterogeneity. Functional traits of Dalbergia nigra and D. miscolobium from the Atlantic Forest and cerrado, respectively, were evaluated under shade (25% of full sunlight) and full sunlight in a nursery experiment. We hypothesised that both species should benefit from high phenotypic plasticity in relation to light. Plasticity was estimated using the relative distance phenotypic index (RDPI). D. miscolobium had lower shoot growth under both light conditions, suggesting it has low competitive capacity in the forest environment, which could explain its limited ability to expand over areas of Atlantic Forest. The studied species exhibited photoprotection strategies under high light and improved light capture under low light. Stomatal conductance, ETR(max) (maximum electron transport rate), PPFD(sat) (saturating photosynthetically active photon flux density), chlorophyll and carotenoid content had higher RDPI than stem morphological traits. Although both species showed considerable phenotypic plasticity, D. miscolobium had higher RDPI for eight of 11 evaluated traits. This high plasticity could be one of the factors that explain the occurrence of this species in a wide range of environmental conditions, from open grassland to dense woodlands, and it could also reflect its adaptation to high light. D. nigra also had considerable plasticity and good growth performance in both shade and full sunlight, but its absence in areas of cerrado suggests that factors other than light limit its occurrence in these habitats.

Fall fertilization of Holm oak affects N and P dynamics, root growth potential, and post-planting phenology and growth

& Introduction For Holm oak (Quercus ilex L.), a flush growing species, nutrient loading during the growing season is difficult and can lead to a low nutrient status of the seedlings. To provide insights about Holm oak nutrient dynamics during fall in the nursery and subsequent planting performance, a factorial nursery experiment was conducted in a mild fall–winter area testing the effects of timing of fertilization (early and late fall) and rate (two doses of a NPK fertilizer that applied 28 and 56 mg N per seedling), followed by an experimental plantation. & Results Biomass, allocation pattern, shoot N and K, and root K were unaffected by both rate and timing of fall fertilization. However, shoot P concentration of fall fertilized plants was significantly increased, and root P concentration was enhanced by applying fertilizer at either the highest rate or during early fall. This revealed a different nutrient dynamics during fall that was dependent on the specific nutrient and plant component. & Discussion Root growth potential was positively correlated to nursery root P concentration. Six months after planting, fall fertilized plants showed higher shoot biomass, higher proportion of new leaves, and faster development, producing leaves earlier compared with unfertilized plants. & Conclusion It is concluded that early fall fertilization promotes nutrient loading of P in Holm oak, with significant effects on root growth potential and field growth by means of a phenologically earlier development and a higher aboveground biomass.