Curcas Seedlings Research Articles

Oxidative stress induced by cobalt in Jatropha curcas seedlings: response of growth and chemical changes

Oxidative stress induced by cobalt in Jatropha curcas seedlings: response of growth and chemical changes

Effect of domestication on water transport in Jatropha curcas seedlings: Relevance of xylem vessels of organs and aquaporin activity in roots

Plant domestication may lead to the suppression of attributes that enable survival in adverse environments. In this context, considering the scarcity of information on water transport in Jatropha curcas L., an experiment was conducted to compare the anatomical variables and hydraulic parameters of roots, stems, and leaves as well as the contribution of aquaporins in water transport of roots between wild and domesticated genotypes. Under irrigation, it was observed 10.2% larger xylem vessel diameters in roots but 7.9% and 11.3% smaller xylem vessel diameters in stems and leaves, respectively, of domesticated genotypes as compared to their wild counterparts. Overall, domestication resulted in 57.5% lower hydraulic resistivity in roots, 87.2% higher hydraulic resistivity in leaves, 22.4% higher vein length per leaf area, 10.5% lower net photosynthetic rate, 36.7% and 42.6% lower theoretical leaf area-specific hydraulic conductivity in roots and stems, respectively. Conversely, in domesticated genotypes, theoretical mass-specific hydraulic conductivity was respectively 58.4% and 57.7% higher in roots and stems. Furthermore, in these genotypes, the root volume was 13% smaller and the contribution of aquaporins to the hydraulic conductivity of roots was greater. In conclusion, domestication has driven the selection of genotypes with roots that are more efficient in conducting water through effects on the anatomy of xylem vessels and activity of aquaporins. However, leaves of such genotypes are more conservative in anatomical and photosynthetic terms. • Domestication of J. curcas resulte in water transport efficient genotypes. • Such efficiency resulted from aquaporin activity and from changes on xylem anatomy. • Domestication improved leaf water distribution, without changes on photosynthesis.

Effect of pruning on Jatropha curcas L. seedlings during the nursery stage

Objective: To determine the effect of pruning on seedlings of Jatropha curcas L. during the nursery stage.Design/Methodology/Approach: To determine the effect of pruning on Jatropha curcas L. seedlings during thenursery stage, a study was carried out at the nursery of the CPA “Abel Santamaría” of the Martí municipality,Cuba. A complete randomized design was used. Three treatments (T) were tested: 1) control (without pruning),2) pruning 30 cm above the soil and seedling defoliation, 3) pruning 30 cm above the soil and without seedlingdefoliation. A descriptive analysis was carried out to determine the survival, regrowth, and number of plantswith primary branches. For the number of leaves and branches, height, and diameter, a simple analysis ofvariance was used, with partitions for each observation.Results: No treatment influenced the survival and regrowth of the plant: up to 2 branches of T2 and T3 wereobtained per plant. A greater height was recorded with T1 (38.63 cm) and this result is different from T2 andT3. The highest number of branches that formed primary branches was obtained by pruning and withoutdefoliation (28 vs. 22 and 0, for T2 and T1, respectively).Study Limitations/Implications. Pruning is an option that can increase Jatropha’s agronomic yield, but it hasnot been studied under nursery conditions.Findings/Conclusions. The pruning of J. curcas seedlings at 30 cm above the ground, under nurseryconditions, with or without defoliation, does not affect the survival or regrowth of the crops and thedevelopment of the primary branches. However, more plants with primary branches and a wider stemdiameter can be obtained by pruning without defoliation

English

This study investigated the influence of different light intensities on the early growth of Jatropha  curcas seedlings. Forty (40) seedlings were randomly selected from the germinated seedlings in the nursery and arrayed under four different treatments (0, 20, 40 and 60% light intensity). The amount of light being received by each of the seedlings was regulated, using constructed wooden box covered with wire gauze (1 mm in size) and measured with photometer. The results on seedlings germination under different light intensity revealed that, the highest mean height (29.2±1.94 cm) was observed in seedlings covered with 60% wire gauze, while the least mean height (27.0±1.24 cm) was observed in the seedlings placed under control treatment (0% wire gauze). Also the highest mean seedlings girth (2.69 ± 0.15 mm) was observed in seedlings not restricted with light intensity (0% wire gauze), while, the least mean girth (2.27±0.08 mm) was found in seedlings restricted with 60% light intensity. The average number of leaves in the four treatments ranges between 6 and 7. The result on analysis of variance (ANOVA) conducted shows a significant effects (P<0.05) of light intensity on J. curcas seedlings girth and number of leaves, while, the seedlings height shows no significant difference (P>0.05). Conclusively, the finding has shown that, J. curcas seedlings required light for its survival, but at varying intensity, and it was noticed that the thicker the light regulator (wire gauze), the lower the amount of light being absorbed by the seedlings. Key words: Jatropha seedling, light intensity, wire gauze, influence survival.

Evaluating the Contribution of Growth, Physiological, and Ionic Components Towards Salinity and Drought Stress Tolerance in Jatropha curcas.

Salinity and drought stress, singly or in combination, are major environmental menaces. Jatropha curcas L. is a biodiesel plant that can tolerate long periods of drought. However, the growth performance and stress tolerance based on physical, chemical, and physiological attributes of this plant have not yet been studied. To address this question, J. curcas seedlings were grown in a completely randomized design in plastic pots filled with soil to evaluate the effects of salinity and drought stresses on growth, ionic composition, and physiological attributes. The experiment consisted of six treatments: control (without salinity and drought stress), salinity alone (7.5 dS m−1, 15 dS m−1), drought, and a combination of salinity and drought (7.5 dS m−1+ Drought, 15 dS m−1+Drought). Our results revealed that, compared with the control, both plant height (PH) and stem diameter (SD) were reduced by (83%, 80%, and 77%) and (69%, 56%, and 55%) under salinity and drought combination (15 dS m−1+Drought) after three, six, and nine months, respectively. There was 93% more leaf Na+ found in plants treated with 15 dS m−1+Drought compared with the control. The highest significant average membrane stability index (MSI) and relative water content (RWC) values (81% and 85%, respectively) were found in the control. The MSI and RWC were not influenced by 7.5 dS m−1 and drought treatments and mostly contributed towards stress tolerance. Our findings imply that J. curcas is moderately tolerant to salinity and drought. The Na+ toxicity and disturbance in K+: Na+ ratio were the main contributing factors for limited growth and physiological attributes in this plant.

Evaluation of Growth Performance of Physic Nut (Jatropha curcas) Seedlings on Different Soils in the Northern Guinea Savanna Agrological Zone of Nigeria

The preliminary study was carried out to evaluate the growth performance of Jatropha curcas seedlings on different soils at the nursery of the Federal College of Forestry Mechanization Afaka, Kaduna. Farm land soil, forest soil and granulated iron stone soil were sourced within the college premises and FRIN/JICA plantation. Jatropha curcas seedlings were sown on the different soils and each was replicated eight (8) times. The experiment was laid out in Complete Randomized Design (CRD). Growth parameters were collected forth nightly and was subjected to Analysis of Variance (ANOVA) and Duncan Multiple Range Test (DMRT). Results revealed that there are significant (P>0.05) difference in the height, stem diameter and number of leaf among the three different soil for the growth assessment. The growth rate recorded from the farm land soil are statistical higher (P>0.05) in leaf width, plant height and stem diameter than the other two soil while the growth parameters assessed were significantly lower (P>0.05) in iron stone soil and forest soil. It is recommended based on the parameters assessed that soil from the farmland gives the best result for raising and nurturing of J. curcas in the nursery without addition of any plant nutrient media.

Evaluation of the injuries caused by Pachycoris torridus (Scopoli, 1772) (Hemiptera: Scutelleridae) in Jatropha curcas (Linnaeus) (Euphorbiaceae)

ABSTRACT The Jatropha curcas species is a perennial plant and easy to manage, being cultivated in many countries because of its high content in oil and the lowest cost of production. This study had as objective to evaluate the injuries caused by the Pachycoris torridus in J. curcas seedlings. Thirty-four days after the planting, 30 J. curcas seedlings were covered with screens and submitted to herbivory of five bugs of the same sex. Morphological and physiological evaluations were conducted 65 days after planting. Seventy-three days after planting, 24 seedlings were submitted to herbivory, using the same methodology as the previous experiment with a quantitative differential of 10 bugs and a batch of 6 plants without insects (control). Evaluations were done 104 days after planting. Male adults (n = 5) of the P. torridus species caused a reduction in the growth and biomass increase in J. curcas seedlings 34 days after planting. After 30 days of herbivores, however the same injuries were not observed in seedlings with 73 days after planting. The injuries (34 days after planting) were considered mild and there was a decrease in the growth and in the biomass accumulation. Upon reaching 73 days after planting, the seedlings became more resistant to the attack of this pest, in such a way that as submitting them to twice the number of insects (n = 10), they did not negatively responded to the herbivory. Finally, the young seedlings were more susceptible to attack, even with low levels of infestation. The pest control should be done when there are signs of infestation at this stage.

Abiotic and biotic drivers of endosymbiont community assembly in Jatropha curcas

AbstractWhile the endosymbiotic communities recruited by plants are known to vary among host species and across environmental gradients, the drivers of community assembly remain poorly understood. We tested the hypothesis that establishment of an endosymbiotic bacterial community is driven primarily by the influence of the abiotic environment on biotic interactions between plant and soil bacteria. We planted sterile Jatropha curcas seedlings at three field sites in Panama and in a greenhouse with soil from those sites. After allowing sufficient time for endosymbiont colonization, we sequenced bacterial 16S rRNA to study the endophytic bacterial community in root and leaf tissue. We compared the communities between field and greenhouse plants and examined associations among the endosymbionts, the soil microbial community, and local abiotic factors. We found that endosymbiont richness and community composition varied between the greenhouse and field, despite plants being grown in the same soil. Plants in each field site harbored a distinct bacterial community, determined by soil microbes and select environmental variables, particularly major plant nutrients. Jatropha curcas can harbor a wide variety of endosymbiotic communities, and the composition of these communities is a product of the local environment. Fertility and agricultural practices may determine the fate of plant symbionts and therefore plant properties modulated through those symbionts.

Ecophysiological responses of Jatropha curcas L. seedlings to simulated acid rain under different soil types

Acid rain is a global environmental problem. Acid rain can affect plants directly by damaging the leaves and indirectly by soil acidifying. Many studies have been conducted to investigate the impacts of acid rain on plant under a single soil type. However, there is little information on the effect of acid rain on plant under different soil types. Jatropha curcas L. is an energy plant widely distributed in acid rain pollution area with various soil types. In this study, we investigated the effects of acid rain (pH2.5, pH3.5, pH4.5, pH5.6) on the growth, physiology, nutrient elements and bacterial community of J. curcas seedlings under different soil types [Red soils (RS), Yellow soils (YS), Yellow-brown soils (YBS), and Purplish soils (PS)]. Acid rain and soil types significantly influence the growth of J. curcas seedlings, and there was a significant interaction between acid rain and soil types. Acid rain (pH 4.5) was beneficial to the growth of J. curcas seedlings, whereas acid rain (pH 2.5 or 3.5) inhibited growth of J. curcas seedlings. The growth of J. curcas seedlings could resist the stress of acid rain by scavenging and detoxification of active oxygen species in leaves. Combined with the increase in relative growth rate of seedlings treated with simulated acid rain at pH 4.5, we inferred that K can stimulate the growth of seedlings. The lower soil pH, cation exchange capacity and base saturation had stronger inhibitory effects on growth of J. curcas seedlings. YBS and PS were beneficial for growth of J. curcas seedlings by higher buffering capacity under acid rain treatments. The phylum Proteobacteria was found to predominate in rhizosphere soils. YBS was favorable to support Proteobacteria growth and reproduction. The redundancy analysis showed that the Cyanobacteria were favorable to growth of J. curcas seedlings.

Heavy metal enrichment and remediation potential of <i>Jatropha curcas</i> Linn seedlings in dumpsite contaminated soil

Heavy metals contamination in water, soil, and plants is a frightening portent around the globe and their bio- amplification through the food chain can cause dangerous health hazards. This study assessed the ability of Jatropha curcas seedlings to uptake and distributes heavy metals totheir tissue parts from dumpsite soil. Heavy metals concentration in dumpsite soils before plantings were Cu (48.01 – 356.71), Zn (39.99 – 437.88), Pb (28.42 – 260.48), Cd (0.69 – 9.75), Co (16.89 – 27.22) and Cr (20.01 – 30.11) while their concentration after planting were Cu (7.01 - 221.22), Zn (6.22- 301.99), Pb (10.26 – 225.98), Cd (0.48 – 4.01), Co (7.09 – 14.61) and Cr (9.56 – 15.89) in mg/kg. Concentration of heavy metal (mg//kg) in roots were Cu (12.99 - 28.99), Zn (11.97 – 30.22), Pb (9.51 – 17.31). Cd (0.19 - 0.99), Co (6.01 – 8.56) and Cr (8.22 – 9.56) and shoots wereCu (25.22- 46.21), Zn (26.09 – 48.01), Pb (11.46 – 17.31), Cd (0.25 – 1.23). Co (9.22 – 12.98) and Cr (10.98 – 14. 01) showed the uptake and enrichment level of heavy metals in the plants. Enrichment and distribution factors were 0.10 to 1.92 and 1.21 to 2.17 respectively. Reduction in the concentration of heavy metals after planting indicated their enrichment in the plant tissues. Medium to high values of enrichment and distribution factors indicated ability of Jatropha carcass seedlings to uptake heavy metals from the soil and distributes them into its parts. This study has further proven the potency of Jatropha curcas seedlings as phytoextractor plants.Keywords: Contamination, enrichment, heavy metals, soil

Physiological and compensatory growth responses of Jatropha curcas (L.) seedlings to simulated herbivory and drought stress

We investigated the physiological and growth responses of Jatropha curcas (L.) seedlings to simulated herbivory stress at different levels of drought stress in experimental greenhouse conditions. Simulated herbivory stress had an effect on photosystem II (PSII) yield of seedlings. The highest decrease of mean PSII yield (63 %) was recorded in seedlings grown under severe drought stress (200 mm yr−1) whereas a moderate herbivory stress (25 %) showed positive effects on mean PSII yield of the seedlings grown under well-watered conditions (1,900 mm yr−1). Stem water content, stem dry biomass and root–shoot ratio (with or without leaves) were significantly affected by the interaction effect of the simulated herbivory and drought stress. Simulated herbivory stress had effects on both root biomass and autumnal height growth rate. The highest above- and below-ground biomasses were obtained in the undamaged and well-watered (1,900 mm yr−1) seedlings, whereas the lowest above- and below-ground biomass were obtained in seedlings exposed to 25 % herbivory stress and grown in extreme drought stress (200 mm yr−1). Our results showed that J. curcas seedlings exhibited under-compensatory growth responses to simulated herbivory stress in all drought stress levels.

Effects of chilling stress on the accumulation of soluble sugars and their key enzymes in Jatropha curcas seedlings.

As osmolytes and signaling molecules, soluble sugars participate in the response and adaptation of plants to environmental stresses. In the present study, we measured the effect of chilling (12°C) stress on the contents of eight soluble sugars in the leaves, cotyledons, stems, and roots of Jatropha curcas seedlings, as well as on the activities of eight rate-limiting enzymes that are critical to the metabolism of those soluble sugars. Chilling stress promoted both starch hydrolysis and soluble sugar accumulation.The soluble sugar contents of the leaves and cotyledons were affected more than that of the stems and roots. Meanwhile, the activities of the corresponding metabolic enzymes (e.g., β-amylase, uridine diphosphate glucose phosphorylase, and sucrose phosphate synthase) also increased in some organs. The gradual increase of soluble neutral alkaline invertase activity in the four studied organs suggested that sucrose catabolic production, such as glucose and fructose, was especially important in determining resistance to chilling stress and hexose signal transduction pathway. In addition, the substantial accumulation of raffinose family oligosaccharides and increase in corresponding metabolic enzyme activity suggested that galactinol and raffinose play an important role in determining the chilling resistance of J. curcas. Together, these findings establish a foundation for determining the relationship between the chilling resistance and soluble sugar accumulation of J. curcas and for investigating the mechanisms underlying sugar signaling transduction and stress responses.

Effects of humidity and dew on the early growth of jatropha (<i>Jatropha curcas</i> (Linn) seedlings in Kano, Nigeria

This study examined the effects of Humidity and Dew on the early growth of Jatropha curcas seedlings in Kano, Nigeria. The experiment was conducted between 20 April, 2014 and 14 July, 2014. Humidity and Dew values were recorded using two Lascar EL- USB data loggers one at each of the two treatments (shade and sun). Early growth characteristics of Jatropha curcas seedlings were recorded at 2, 4, 6, 8, 10 and 12 weeks after sowing (WAS). Line graphs were used to describe the mean humidity and dew values. Table was used to show the early growth characteristics of Jatropha curcas. Pearson’s Product Moment Correlation was used to test whether there is significant relationship between the Humidity and Dew and the early growth characteristics of Jatropha curcas seedlings. The test was carried out at 0.05 significant levels. The Correlation results showed that there is a significant relationship between the Humidity and Dew and the early growth characteristics of Jatropha curcas seedlings in the sun treatment and also between Dew and seedlings emergence in both shade and sun treatments however; it showed that there is no significant relationship between the Humidity and Dew and the early growth characteristics of Jatropha curcas seedlings in the shade treatment. Jatropha curcas seedlings nurtured in the sun grows faster than their shade counterparts due to the vital role played by sunlight during photosynthesis and other growth processes. Finally, it is concluded that there is a significant relationship between Humidity and Dew and the early growth characteristics of Jatropha curcas seedlings nurtured in the sun.Keywords: Dew, Early growth, Humidity, and Jatropha curcas

Pre-colonized seedlings with arbuscular mycorrhizal fungi: an alternative for the cultivation of Jatropha curcas L. in salinized soils

The aim of this study was to test the hypothesis that Jatropha curcas L. seedlings previously inoculated with arbuscular mycorrhizal fungi (AMF) in non-salinized soil and later transplanted to salinized soil are more tolerant to saline stress. The experiment was conducted in greenhouse using a randomized block design in a 4 × 2 factorial scheme. The first factor consisted of salinized soil with electrical conductivity (EC) of 2, 5, 8 and 10 dS/m, and the second consisted of non-colonized plants, and plants that were pre-colonized with AMF, with eight replicates. Salt had a deleterious effect on plants non-inoculated with AMF, which showed reduced growth and photosynthetic activity and increased stress indicators, such as lipid peroxidation, proline accumulation, and high antioxidant enzymatic activity. On the other hand, pre-colonized plants were less affected by the presence of salt in the soil. Seedlings pre-inoculated with AMF presented the same growth rate and photosynthetic activity in all saline treatments. No increase in lipid peroxidation and antioxidant enzymatic activity was observed in seedlings pre-inoculated with AMF even under high saline concentration of 10 dS/m EC. The results suggest the existence of a mechanism to mitigate the effects of saline stress on pre-colonized seedlings. Therefore, pre-colonized J. curcas seedlings are an alternative for the cultivation of this species in salinized soils.

Exogenous nitric oxide improves salt tolerance during establishment of Jatropha curcas seedlings by ameliorating oxidative damage and toxic ion accumulation

Jatropha curcas is an oilseed species that is considered an excellent alternative energy source for fossil-based fuels for growing in arid and semiarid regions, where salinity is becoming a stringent problem to crop production. Our working hypothesis was that nitric oxide (NO) priming enhances salt tolerance of J. curcas during early seedling development. Under NaCl stress, seedlings arising from NO-treated seeds showed lower accumulation of Na+ and Cl− than those salinized seedlings only, which was consistent with a better growth for all analyzed time points. Also, although salinity promoted a significant increase in hydrogen peroxide (H2O2) content and membrane damage, the harmful effects were less aggressive in NO-primed seedlings. The lower oxidative damage in NO-primed stressed seedlings was attributed to operation of a powerful antioxidant system, including greater glutathione (GSH) and ascorbate (AsA) contents as well as catalase (CAT) and glutathione reductase (GR) enzyme activities in both endosperm and embryo axis. Priming with NO also was found to rapidly up-regulate the JcCAT1, JcCAT2, JcGR1 and JcGR2 gene expression in embryo axis, suggesting that NO-induced salt responses include functional and transcriptional regulations. Thus, NO almost completely abolished the deleterious salinity effects on reserve mobilization and seedling growth. In conclusion, NO priming improves salt tolerance of J. curcas during seedling establishment by inducing an effective antioxidant system and limiting toxic ion and reactive oxygen species (ROS) accumulation.

An in Vitro Grafting Technique for Enhancing the Growth of Isolated Buds and Shoots in Jatropha Curcas

In most Agrobacterium-mediated Jatropha curcas transformation systems, antibiotics are used for suppressing the growth of the bacteria. However, these antibiotics could also hinder largely the further growth of the resulted buds. To tackle this problem, grafting methods were tested by using J. curcas buds and shoots isolated from seedlings as scions and the lower part of J. curcas seedlings as stocks. It was found that the most suitable stocks were those prepared from five days old seedlings and had the upper part radical. In later experiments, significant enhancement on the growth of buds in culture was confirmed in 1/2 MS medium containing0.3 mg/l indole-3-butyric acid (IBA).With the help of above established grafting methods by grafting the buds to the stocks, the growth of the grafted buds could be effectively enhanced.

Physiological Responses to Drought Stress in Jatropha curcas Seedlings

Physiological Responses to Drought Stress in Jatropha curcas Seedlings

CHARACTERISTICS OF COMPOSTED BIO-TOILET RESIDUE AND ITS POTENTIAL USE AS A SOIL CONDITIONER

Bio-toilet is a dry toilet where human excreta is trapped in a lignocelluloses soil matrix such as wood sawdust, then it is decomposed by aerobic bacteria to organic compost rich in minerals such as N, P, and K. The study aimed to characterize the bio-toilet residue and its potential use as a soil conditioner for Jatropha curcas. The study was conducted in a private school of Daarut Tauhid in Bandung West Java. A bio-toilet S-50 type of Japan was constructed consisting of a composting chamber, mixer, heater, exhaust fan, and closet. The composting chamber was filled with 63 kg of Albizzia sawdust. Feces and urine was loaded daily by 54 students for 122-day observation. At the end of observation, the decomposed bio-toilet residue was evaluated for its physical properties such as bulk density (rb), porosity (%), and water retention (WR). Chemical properties such as pH, C/N ratio, N, P, and K, as well as microbiological properties such as numbers of bacteria, fungi, and worm eggs were evaluated at 14 and 122 days of decomposition process. Effect of the composted bio-toilet residue as plant growth media was evaluated using J. curcass as a plant indicator. Before it was used as a growth media, the composted bio-toilet residue was dried in a room temperature for 30 days. The experiment was designed in a completely randomized design 2 x 4 factorial with three replications. The first factor was the rate of composted biotoilet residue, i.e., 0, 20, 40, and 60% based on weight of the growth media mixture (1500 g pot-1), and the second was NPK fertilizer addition at 0 and 2 g pot-1. Each pot was planted with 2-month old of J. curcas seedlings. Parameters evaluated were leaf number, leaf area, stem height, and stem diameter measured at 12 weeks after planting. The results showed that the biotoilet residue was suitable as soil conditioner because it had high porosity (76%), low bulk density (0.19 g cm-3), high water retention (2.6 ml g-1 DM), neutral pH (6.9), C/N ratio 27, and contained N, P, K, and Na of 1.73, 1.15, 1.03, and 0.88%, respectively. Its microbial count showed only two kinds of bacteria, i.e., Klebsiella pneumonia and Escherichia coli, detected at 14 and 122 days of bio-toilet usage. The composted bio-toilet residue improved vegetative performances of J. curcas as indicated by increasing leaf number, leaf area, stem height, and stem diameter.

CHARACTERISTICS OF COMPOSTED BIO-TOILET RESIDUE AND ITS POTENTIAL USE AS A SOIL CONDITIONER

Bio-toilet is a dry toilet where human excreta is trapped in a lignocelluloses soil matrix such as wood sawdust, then it is decomposed by aerobic bacteria to organic compost rich in minerals such as N, P, and K. The study aimed to characterize the bio-toilet residue and its potential use as a soil conditioner for Jatropha curcas. The study was conducted in a private school of Daarut Tauhid in Bandung West Java. A bio-toilet S-50 type of Japan was constructed consisting of a composting chamber, mixer, heater, exhaust fan, and closet. The composting chamber was filled with 63 kg of Albizzia sawdust. Feces and urine was loaded daily by 54 students for 122-day observation. At the end of observation, the decomposed bio-toilet residue was evaluated for its physical properties such as bulk density (rb), porosity (%), and water retention (WR). Chemical properties such as pH, C/N ratio, N, P, and K, as well as microbiological properties such as numbers of bacteria, fungi, and worm eggs were evaluated at 14 and 122 days of decomposition process. Effect of the composted bio-toilet residue as plant growth media was evaluated using J. curcass as a plant indicator. Before it was used as a growth media, the composted bio-toilet residue was dried in a room temperature for 30 days. The experiment was designed in a completely randomized design 2 x 4 factorial with three replications. The first factor was the rate of composted biotoilet residue, i.e., 0, 20, 40, and 60% based on weight of the growth media mixture (1500 g pot-1), and the second was NPK fertilizer addition at 0 and 2 g pot-1. Each pot was planted with 2-month old of J. curcas seedlings. Parameters evaluated were leaf number, leaf area, stem height, and stem diameter measured at 12 weeks after planting. The results showed that the biotoilet residue was suitable as soil conditioner because it had high porosity (76%), low bulk density (0.19 g cm-3), high water retention (2.6 ml g-1 DM), neutral pH (6.9), C/N ratio 27, and contained N, P, K, and Na of 1.73, 1.15, 1.03, and 0.88%, respectively. Its microbial count showed only two kinds of bacteria, i.e., Klebsiella pneumonia and Escherichia coli, detected at 14 and 122 days of bio-toilet usage. The composted bio-toilet residue improved vegetative performances of J. curcas as indicated by increasing leaf number, leaf area, stem height, and stem diameter.

Impacts of simulated drought stress and artificial damage on concentrations of flavonoids in Jatropha curcas (L.), a biofuel shrub.

We studied the possible roles of flavonoids in the antioxidant and antiherbivore chemistry in Jatropha curcas (L.), a Latin American shrub that holds great potential as a source of biofuel. Changes in flavonoid concentrations in the leaves of J. curcas seedlings exposed to artificial damage and to different rainfall patterns were assessed by applying a 32-factorial experiment in a greenhouse. The concentrations of different flavonoids in the leaves of seedlings were significantly affected by interaction effects of artificial damage, drought stress and age of the seedling. The highest flavonoid concentrations were obtained in seedlings imposed to the highest percentage of artificial damage (50%) and grown under extreme drought stress (200mmyear-1). In this treatment combination, flavonoid concentrations were three-fold as compared to seedlings exposed to the same level of artificial damage but grown in 1900mmyear-1 rainfall application. Without artificial damage, the concentration of flavonoids in the seedlings grown in 200mmyear-1 rainfall application was still two-fold compared to seedlings grown in higher (>800mmyear-1) rainfall applications. Thus, the observed flavonoid concentration patterns in the leaves of J. curcas seedlings were primarily triggered by drought stress and light rather than by artificial damage, suggesting that drought causes oxidative stress in J. curcas.