Leaf Tissue Concentrations Research Articles

Effect of Nitrogen and Potassium Rates on Early Development of Macaw Palm

ABSTRACT The economic exploitation of macaw palm [Acrocomia aculeate(Jacq.) Lodd. ex Mart.] is currently in transition, from extractivism to agricultural cultivation, thus requiring studies on the fertilization of the crop. This study evaluated the response of three genotypes of macaw palm to increasing rates of nitrogen and potassium, grown in the field until the 2nd year and to establish reference contents of mineral nutrients in the leaf. The experiment was a split-plot randomized block design with five main treatments (N and K rates) and three secondary treatments (genotypes), with three replications, each plot containing three plants. Plant height, leaf number, vigor, and nutrient contents in leaf tissues were evaluated at the end of 2nd year of cultivation. Differential responses were observed among genotypes, indicating that some genotypes are more efficient in the use of mineral inputs. There was a differentiated and positive response to increasing side-dressed N and K rates in the vegetative development of macaw genotypes until the 2nd year of field cultivation, indicating variability in the species in terms of nutrient use efficiency. The N and K fertilization rate corresponding to 360 g N + 480 g K2O per plant, in four split applications over the two years of cultivation, was insufficient to induce maximum vegetative development in the three macaw genotypes. There was no variation in macro- and micronutrient contents in leaf dry matter of the three macaw genotypes.

Estimation of potassium concentration in oil palm (Elaeis guineensis Jacq.) leaf tissue by simple and inexpensive water extraction method

ABSTRACTEstimation of potassium (K) concentration in oil palm leaf tissue is routinely carried out in oil palm plantations to manage fertilizer application for getting higher fresh fruit bunch (FFB) production. Since K in plant tissue is not bound to organic complexes and it is extractable by water, this study was carried out to extract K from oil palm leaf tissue by water extraction method. The results were compared with other established methods like 1 normal (N) ammonium acetate (NH4OAc) extraction, 0.5 N hydrochloric acid (HCl) extraction, and diacid digestion. The proposed water extraction method consists of shaking of 0.5 g finely ground oil palm leaf tissue with distilled water at 1:60 ratio [sample-to-water weight (w)/volume (v)] for a period of 20 min in a reciprocating shaker, filtration of the content, and measurement of K concentration in filtrate by flame photometer. The results of analysis of 30 oil palm leaf samples collected from various production systems under different soil types and management practices for K concentration revealed the close agreement of water extraction method with other established methods. The mean value of K extracted by water extraction method was within 1–10% of the K extracted by other established methods. Water-extractable K was significantly correlated with K extracted by other methods and it could be predicted by other methods. The values of standard error and coefficient of variation for K extracted by different methods were very low, which indicated that the water extraction method was comparable with other established methods.

Transcriptional transitions in Nicotiana benthamiana leaves upon induction of oil synthesis by WRINKLED1 homologs from diverse species and tissues.

BackgroundCarbon accumulation and remobilization are essential mechanisms in plants to ensure energy transfer between plant tissues with different functions or metabolic needs and to support new generations. Knowledge about the regulation of carbon allocation into oil (triacylglycerol) in plant storage tissue can be of great economic and environmental importance for developing new high-yielding oil crops. Here, the effect on global gene expression as well as on physiological changes in leaves transiently expressing five homologs of the transcription factor WRINKLED1 (WRI1) originating from diverse species and tissues; Arabidopsis thaliana and potato (Solanum tuberosum) seed embryo, poplar (Populus trichocarpa) stem cambium, oat (Avena sativa) grain endosperm, and nutsedge (Cyperus esculentus) tuber parenchyma, were studied by agroinfiltration in Nicotiana benthamiana.ResultsAll WRI1 homologs induced oil accumulation when expressed in leaf tissue. Transcriptome sequencing revealed that all homologs induced the same general patterns with a drastic shift in gene expression profiles of leaves from that of a typical source tissue to a source-limited sink-like tissue: Transcripts encoding enzymes for plastid uptake and metabolism of phosphoenolpyruvate, fatty acid and oil biosynthesis were up-regulated, as were also transcripts encoding starch degradation. Transcripts encoding enzymes in photosynthesis and starch synthesis were instead down-regulated. Moreover, transcripts representing fatty acid degradation were up-regulated indicating that fatty acids might be degraded to feed the increased need to channel carbons into fatty acid synthesis creating a futile cycle. RT-qPCR analysis of leaves expressing Arabidopsis WRI1 showed the temporal trends of transcripts selected as ‘markers’ for key metabolic pathways one to five days after agroinfiltration. Chlorophyll fluorescence measurements of leaves expressing Arabidopsis WRI1 showed a significant decrease in photosynthesis, even though effect on starch content could not be observed.ConclusionsThis data gives for the first time a general view on the transcriptional transitions in leaf tissue upon induction of oil synthesis by WRI1. This yields important information about what effects WRI1 may exert on global gene expression during seed and embryo development. The results suggest why high oil content in leaf tissue cannot be achieved by solely transcriptional activation by WRI1, which can be essential knowledge in the development of new high-yielding oil crops.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0579-1) contains supplementary material, which is available to authorized users.

EFFECT OF APPLICATION METHODS AND CONCENTATION OF CHITOSAN ON GROWTH, YIELD, TUBER ROOTS QUALITY AND STORABILITY OF SWEET POTATO PLANTS GROWN UNDER SANDY SOIL CONDITIONS

This work was carried out during the two successive summer seasons of 2013 and 2014 at a Private Vegetable Farm in El-Khattara distract, Sharkia, Governorate, to investigate the effect of different application methods and concentrations of chitosan ( 0, 0.025, 0.075 and 0.125 %) on growth , yield , tuber roots quality and storability of sweet potato cv. Buregard grown under sandy soil conditions using drip irrigation system. Dipping the base of the stem cuttings in chitosan solution before planting + foliar spraying of the plants with chitosan was the best method for increasing dry weight of shoots, N,P and K uptake by shoots, marketable yield and total yield and also, for decreasing weight loss (%) and decay (%) in tuber roots during storage period. Chitosan solution 0.075 % increased growth, average tuber weight , total yield, starch and total sugar in tuber roots, whereas chitosan 0.125 % increased chlorophyll a, total (a+b) in leaf tissues, N,P and K uptake by shoots and marketable yield and also recorded minimum values of weight loss and decay (%) in tuber roots during storage period. Dipping the base of the stem cuttings in 0.075 % chitosan solution before planting + spraying plants with 0.075 % chitosan solution gave the highest values of vine length , dry weight of shoots/ plant, chlorophyll a and total chlorophyll ( a+b) concentration in leaf tissues, average weight of tuber root, total yield , whereas the same treatment gave the lowest values of weight loss percentage and decay (%) in tuber roots during storage period. On the other hand, the base of stem cuttings in 0.125 % chitosan solution before planting + spraying plants with 0.125 % chitosan gave the highest values of N,P and K uptake, marketable yield, starch and total sugar contents in tuber roots. Conclusively, from the foregoing results of this study, it could be concluded that, under the same conditions, dipping the base of the stem cutting in 0.075 % chitosan solution before planting + spraying plants with 0.075 % chitosan solution three times at 15 days intervals beginning 25 days after transplanting gave the best interaction treatment for increasing plant growth, yield and its components, tuber roots quality and storability of sweet potato plants.

Boron accumulation and tolerance in sweet basil (Ocimum basilicum L.) with green or purple leaves

Background and aims There is a wide variability in plant tolerance to boron (B) toxicity, which is often associated with the ability to limit B accumulation. This study was conducted on two cultivars of sweet basil (Ocimum basilicum L.) with different B tolerance: ‘Tigullio’, less tolerant and with green leaves; ‘Red Rubin’, more tolerant and with purple leaves. The main goal was to verify whether the greater B tolerance of ‘Red Rubin’ is attributable to an exclusion mechanism. Methods In three greenhouse experiments, plants were grown hydroponically with solution B concentration ranging from 0.25 (control) to 25 mg L −1 . Results Tissue B concentration increased with increasing B supply. Boron concentrations in root and leaf tissues were comparable in ‘Tigullio’ and ‘Red Rubin’ or even higher in the purple cultivar. Boron supply did not affect the leaf concentration of total phenolic compounds and other nutrients. Leaf concentrations of total phenols and rosmarinic acid were remarkably higher in ‘Red Rubin’ than in ‘Tigullio’. Conclusions The greater B tolerance of ‘Red Rubin’ was associated with the ability to withstand higher concentrations of this element in plant tissues rather than to reduced B accumulation in the shoot. The high phenolic content was thought to contribute to the B tolerance of ‘Red Rubin’.

Mesotrione Activity on Crabgrass (Digitariaspp.) as Influenced by Nitrogen Fertilization Rate, Source, and Timing

Mesotrione, a 4-hydroxyphenylpyruvate dioxygenase-inhibiting herbicide, is labeled for PRE and POST crabgrass control. It has enhanced efficacy on smooth and large crabgrass when applied in conjunction with soil-applied nitrogen (N). The objectives of this study, using crabgrass as the weed species, were to (1) determine the influence of N rate and tissue N concentration on mesotrione activity, (2) determine the influence of N source on mesotrione activity, and (3) determine the influence of N application timing on mesotrione activity. Large crabgrass plants that received 12 kg N ha−1or more before mesotrione application had more bleached and necrotic leaves compared with plants that received 0 kg N ha−17 d after treatment (DAT) in the greenhouse. Although N application rates as high as 98 kg N ha−1were tested, 90% leaf bleaching and necrosis were observed with rates of 8.9 or 10.1 kg N ha−1in Tennessee and Indiana, respectively. Nitrogen concentration in large crabgrass leaf and stem tissue on the day of the mesotrione application was closely related to the bleaching and necrosis symptoms observed 7 DAT. Although N rate influenced mesotrione activity, N source did not. Nitrogen application timing was also important, with N applications 3, 1, and 0 d before a mesotrione application having the highest percentage of bleached and necrotic leaves in greenhouse experiments. Both greenhouse and field trials support the finding that N applications in proximity to the mesotrione application enhance herbicide activity. Thus, practitioners can pair N and POST mesotrione applications together or in proximity to enhance crabgrass control.

Inhibition of mercury release from forest soil by high atmospheric deposition of Ca2+ and [formula omitted

As one of the most important natural mercury (Hg) sources, soil release (emission to the atmosphere or leaching to soil water) depends on various factors, some of which can be affected by atmospheric deposition. We studied the effect of flue gas desulfurization gypsum (FGDG) addition on soil Hg release in a Masson pine (Pinus massoniana) forest in southwestern China. FGDG addition simulated atmospheric deposition of Ca2+, SO42- and Hg, which are commonly high in China. Results showed that Hg concentration in soil water decreased with the gypsum treatment, suggesting that the mobility of Hg in mineral soil was reduced. Moreover, the application of gypsum also seems to have decreased Hg emission from the soil, shown by the lower Hg contents in leaf tissues of ground vegetation in the treated plots than in the reference. Both Hg mobility in the soil and Hg emission to the atmosphere were decreased despite the additional Hg input from FGDG. The decreased DOC concentration in soil water and the elevated organic sulfur content in the soil Oe & Oa horizons were speculated to result in an enhanced capacity of surface soil to bind Hg, and thus to reduce Hg release from the soil. However, with the increasingly stringent control of particulate matter (PM) and sulfur dioxide (SO2) emissions in China, the deposition of Ca2+ and SO42- is expected to decrease, and their ability to inhibit soil Hg release is likely to decline in the future.

Role of arbuscular mycorrhizal fungi in alleviating the adverse effects of acidity and aluminium toxicity in zucchini squash

The aim of the current research was to assess whether arbuscular mycorrhizal (AM) inoculation would give an advantage to overcome acidity and aluminium (Al) toxicity problems and to study the changes induced by AM at agronomical and physiological level. A greenhouse experiment was carried out, to determine yield, growth, fruit quality, SPAD index, electrolyte leakage, and mineral composition of zucchini squash (Cucurbita pepo L.) inoculated (+AM) and noninoculated (−AM) with arbuscular mycorrhizal and cultured in pots filled with quartziferous sand. Plants were supplied with nutrient solutions having different pH and aluminium concentration (pH 6.0, pH 3.5 or pH 3.5+Al). The low pH treatment had the same nutrient composition plus HCl, whereas the aluminium treatment (pH 3.5+Al) was induced by adding 1.0mM of AlCl3·6H2O. The AM root colonization was higher in the control treatment (pH 6.0; 48.5%), followed by pH 3.5 (23.4%), and finally in pH 3.5+Al treatment (17.1%). Significant depression of yield, biomass, SPAD index, leaf area, N, P, Mg, Fe, and Zn concentration in leaf tissue was observed in response to low pH level with more detrimental effects with pH 3.5+Al. The inoculated plants under acidity and Al conditions had higher total, marketable yield, and total biomass than noninoculated plants. Zucchini-fruit quality, in particular fruit dry matter, total soluble-solids content, P, and Fe concentration, was improved by mycorrhizal colonization. Mycorrhized zucchini plants grown under acidity and Al conditions had a higher macronutrient concentration in leaf tissue compared to noninoculated plants. The better crop performance in inoculated plants were related to the capacity of maintaining higher SPAD index, lower electrolyte leakage, and better nutritional status (high N, P, K, Ca, Mg, Fe, Zn, and B and low Al accumulation) in response to Al stress with respect to −AM plants.

Perchlorate Uptake and its Effect on Physiological, Biochemical and Growth Parameters of Eucalyptusplant under Ammonium Perchlorate Stress

Perchlorate is a significant environmental pollutant affecting public health. When entered in ecosystem it is highly toxic. Present investigation focused on the influence of perchlorate on physiological and biochemical parameters of Eucalyptus citriodora and also its accumulation in plant tissue and depletion from soil. Eucalyptus plants were treated with varying concentration of ammonium perchlorate from 1000ppm, 2000ppm, 5000ppm and 10000 ppm. Perchlorate inside the plant tissue and in soil was quantified at regular intervals. Amount of perchlorate inside plant tissue observed to increase with number of days after treatment and is proportional to concentration of perchlorate in soil. Morphological characters like shoot length, root length, number of leaf were observed to decrease with increasing concentration of perchlorate. The present study revealed decrease in chlorophyll and reducing sugar content in leaf tissue under varying concentration of perchlorate and is indirectly proportional to amount of perchlorate. While total protein, proline, and phenol content showed a gradual increase with increase in concentration of perchlorate and in different experimental set up, suggesting increase in non-enzymatic stress parameters with increased level of toxicity. An increased activity of peroxidase enzyme was observed with increased dose of ammonium perchlorate. It can be concluded that perchlorate related influence on plant are both qualitative and quantitative and depends upon its concentration and duration of exposure.

Wild Edible Species with Phytoremediation Properties

High salinity is an increasing environmental problem that severely affects agriculture by both limiting crop yield and available agricultural land. United Nations Food and Agriculture Organization report that approximately 20-30% of all agricultural land is becoming saline, whereas about 8% of all salt-affected soils are human-induced. In the Mediterranean basin there are many wild species that are consumed as greens or herbs, whereas a few of them have been introduced as alternative crops (e.g. Cichorium spinosum L.).In the present study, various native species (Hymenonema graecum, Reichardia picroides, Sonchus oleraceus, Taraxacum officinale, Urospermum picroides and Picris echioides) were grown under medium to high salinity levels (1.8-8 dS/m) by adding NaCl to irrigation water, in order to evaluate their tolerance under salinity stress conditions. From the results it is observed that Reichardia picroides, Sonchus oleraceus and Urospermum picroides could be considered as tolerant species since their yield was not affected by high salinity, whereas the Na content in leaf tissues increased with increasing salinity for all the species (except for Urospermum picroides) implicating accumulating mechanisms that aleviate the negative effects of salinity on plant growth. For the rest of the species, salinity affected significantly yield, especially when high levels (8 dS/m) were applied.Therefore, these species could be a useful means to alleviate problems of saline soils by cultivating them for phytoremediation purposes, whereas the final products could be marketed as edible herbs. In this context, they could be cultivated in areas where irrigation water is of low quality due to high content of NaCl (coastal areas or areas where ground water is saline), allowing farmers to gradually improve their soils and render them available for other conventional species.

Carbon and Nitrogen Content in leaf Tissue of Different Plant Species, Northeastern Mexico

The present study was undertaken to determine carbon and nitrogen content among 40 plant species of diverse growth habit with a view to select species with high carbon fixation (carbon content) and nitrogen content. In this study, we selected few species with high carbon fixation such as Eugenia caryophyllata (51.66%), Litsea glauscensens (51.54%), Rhusvirens (50.35%), Gochantia hypoleuca (49.86%), Pinus arizonica (49.32%), Eryobotrya japonica (47.98%), Tecoma stans (47.79%), Rosamarinus officinalis (47.77%). Few of these species could be recommended for plantation in CO2 polluted areas to reduce carbon load. In addition these, high carbon concentration could serve as good source of energy. We selected few species with high nitrogen content such as Mimosa malacophylla (8.44%), Capscicum annuum (6.84%), Moringa oleifer (6.25%), Azadirachta indica (5.85%), Eruca sativa (5.46%), Rosamarinus officinalis (5.40%), Mentha piperita (5.40%). These species could serve as good sources of nitrogen for health care. We selected few species with high C/N ratio such Arbutusxalapensis (26.94%), Eryngium heterophyllum (24.29%), Rhus virens (22.52%), Crotonsuaveleons (20.16%), Cinnamomum verum (19.89%) which may be related to high production of secondary metabolites and antioxidants.

Chlorophyll Content Assay to Quantify the Level of Necrosis Induced by Different R Gene/Elicitor Combinations after Transient Expression.

This assay can be used to rapidly and accurately quantify levels of leaf necrosis induced after transient expression of R genes and elicitor combinations (Harris et al., 2013). It is based on the inverse correlation between level of necrosis and chlorophyll content in leaf tissue. It is adapted from the calculations described by (Strain et al., 1971).

Nutrient cycling in an agroforestry alley cropping system receiving poultry litter or nitrogen fertilizer

Optimal utilization of animal manures as a plant nutrient source should also prevent adverse impacts on water quality. The objective of this study was to evaluate long-term poultry litter and N fertilizer application on nutrient cycling following establishment of an alley cropping system with eastern black walnut (Juglans nigra L.), pecan [Carya illinoensis (Wangenh.) K. Koch], and northern red oak (Quercus rubra L.) trees and orchardgrass (Dactylis glomerata L.). One half of a 4.25-ha site in northwestern Arkansas USA received broadcast applications of 3.9–6.7 Mg ha−1 fresh poultry litter and the other half 50–76 kg ha−1 N as NH4NO3 fertilizer each spring from 2001 to 2008. Macronutrient (N, P, K, Ca, Mg, and S) and micronutrient (Na, Fe, Mn, Zn, and Cu) concentrations in soil, forage, and tree leaf tissue were monitored along with NO3-N in soil water and groundwater. Poultry litter application resulted in significantly increased concentrations of each macronutrient except S with increases from 6.3 (N) to 121 % (P). Nitrogen fertilizer application resulted in decreased concentrations from 2.1 (N) to 60.9 % (S) for all macronutrients except Ca. Patterns of nutrient content in forage and tree leaf tissue did not generally follow patterns of soil nutrient concentrations suggesting nutrient sufficiency in most years and that climate and plant growth had a greater effect on nutrient uptake. Soil P with litter application increased 41.3 mg kg−1 over 7 years (from 34.1 to 75.4), which may necessitate a lower litter application rate to avoid excessive P runoff.

Comparison Study on Soil Physical and Chemical Properties, Plant Growth, Yield, and Nutrient Uptakes in Bulb Onion from Organic and Conventional Systems

This study aimed to compare agricultural practices, soil physical and chemical properties, growth characteristics, and nutrient uptake of bulb onions from organic and conventional farms in southeastern Korea during the 2011–12 growing season. Soil and plant samples were collected from eight certified organic fields managed organically for more than 5 years and eight conventional fields adjacent to the organic fields. The amounts of nutrients applied to onion fields were approximately two times greater with the conventional methods than with organic methods. However, the soil physical and chemical properties were not significantly different between the organic and conventional systems, except for NO3-N in early May. Growth characteristics were significantly different in early April with organic bulb yield of 55.9 t·ha−1, which was 21.8% lower than conventionally produced onions. Yield reduction in organic onions was the result of lower large-sized (8 cm or greater) bulb yield compared with conventional production. In the conventional system, phosphorus (P) and potassium (K) content of leaf tissue in early April, and nitrogen (N) and P content of bulb tissue in early May were higher than those in the organic system. Uptake of all nutrients was greater in the conventional onions compared with the organic onions, except for leaf tissue at harvest. In conclusion, organic onions began to grow and absorb soil nutrients later than the conventional onions in the initial vegetative growth stage. Moreover, it led to an organic onion producing a lower bulb yield. To accelerate the initial growth of the organic onion plant, agricultural practices need to be modified. Modifications that may help include using larger sized seedlings at transplanting, covering the plants with nonwoven fabric or transparent plastic film to increase warmth during winter, and harvesting the onions 1 week later than the conventional onions.

Effectiveness of remediation of metal-contaminated mangrove sediments (Sydney estuary, Australia).

Industrial activities and urbanization have had a major consequence for estuarine ecosystem health and water quality globally. Likewise, Sydney estuary has been significantly impacted by widespread, poor industrial practices in the past, and remediation of legacy contaminants have been undertaken in limited parts of this waterway. The objective of the present investigation was to determine the effectiveness of remediation of a former Pb-contaminated industrial site in Homebush Bay on Sydney estuary (Australia) through sampling of inter-tidal sediments and mangrove (Avicennia marina) tissue (fine nutritive roots, pneumatophores, and leaves). Results indicate that since remediation 6 years previously, Pb and other metals (Cu, Ni and Zn) in surficial sediment have increased to concentrations that approach pre-remediation levels and that they were considerably higher than pre-settlement levels (3-30 times), as well as at the reference site. Most metals were compartmentalized in fine nutritive roots with bio-concentration factors greater than unity, while tissues of pneumatophores and leaves contained low metal concentrations. Lead concentrations in fine nutritive root, pneumatophore, and leaf tissue of mangroves from the remediated site were similar to trees in un-remediated sites of the estuary and were substantially higher than plants at the reference site. The situation for Zn in fine nutritive root tissue was similar. The source of the metals was either surface/subsurface water from the catchment or more likely remobilized contaminated sediment from un-remediated parts of Homebush Bay. Results of this study demonstrate the problems facing management in attempting to reduce contamination in small parts of a large impacted area to concentrations below local base level.

Measuring whole plant CO2 exchange with the environment reveals opposing effects of the gin2–1 mutation in shoots and roots of Arabidopsis thaliana

Using a cuvette for simultaneous measurement of net photosynthesis in above ground plant organs and root respiration we investigated the effect of reduced leaf glucokinase activity on plant carbon balance. The gin2–1 mutant of Arabidopsis thaliana is characterized by a 50% reduction of glucokinase activity in the shoot, while activity in roots is about fivefold higher and similar to wild type plants. High levels of sucrose accumulating in leaves during the light period correlated with elevated root respiration in gin2–1. Despite substantial respiratory losses in roots, growth retardation was moderate, probably because photosynthetic carbon fixation was simultaneously elevated in gin2–1. Our data indicate that futile cycling of sucrose in shoots exerts a reduction on net CO2 gain, but this is over-compensated by the prevention of exaggerated root respiration resulting from high sucrose concentration in leaf tissue.

Physiological Changes and Expression of SOD and P5CS Genes in Response to Water Deficit in Sugarcane

Drought stress is one of the major environmental stresses affecting growth and productivity of sugarcane in many areas of tropical and subtropical India. Resistance to water deficit in plants can occur through proline accumulation and higher expression of antioxidant enzymes. The differential expression patterns of drought-responsive genes in different plant tissues at different growth stages could provide an opportunity to characterize the traits associated with yield advantage under drought and to understand the physiological and molecular mechanisms that confer increased drought tolerance. Present study was aimed to examine the effect of short term water deficit on physiological attributes and expression of superoxide dismutase (SOD), and P5CS (pyrroline-5-carboxylate synthetase) genes using two sugarcane varieties, CoLk 94184 (an early maturing) and BO 91 (a mid late maturing). Single bud setts of two varieties of sugarcane were planted in earthen pots filled with soil in the month of February, 2013. After about 60 days of planting, water deficit was created by withholding water supply for 24, 48, and 72 h along with control and recovery treatment. Results obtained indicated increased proline content in leaf tissues with an increase in duration of water deficit; highest increase was observed at 72 h of water deficit conditions. Early maturing variety, CoLk 94184 showed higher accumulation of proline content with severe wilting as compared to mid late maturing variety BO 91. RWC, chlorophyll and carotenoids contents and SPAD reading decreased with water deficit level, while, recovery treatment showed increase in these attributes in both the varieties. Specific activity of SOD and peroxidase enzymes increased due to water deficit conditions. Quantitative expression of SOD and P5CS genes increased only up to 48 h of water deficit treatment and at 72 h treatment their expression was low. After recovery treatment, gene expression increased in both the varieties. Higher expression of SOD and P5CS genes up to certain level of water deficit (48 h), proline content and activity of antioxidant enzymes (SOD and peroxidase) may help in tolerance to water deficit condition.

Exogenous methyl jasmonate treatment increases glucosinolate biosynthesis and quinone reductase activity in kale leaf tissue.

Methyl jasmonate (MeJA) spray treatments were applied to the kale varieties ‘Dwarf Blue Curled Vates’ and ‘Red Winter’ in replicated field plantings in 2010 and 2011 to investigate alteration of glucosinolate (GS) composition in harvested leaf tissue. Aqueous solutions of 250 µM MeJA were sprayed to saturation on aerial plant tissues four days prior to harvest at commercial maturity. The MeJA treatment significantly increased gluconasturtiin (56%), glucobrassicin (98%), and neoglucobrassicin (150%) concentrations in the apical leaf tissue of these genotypes over two seasons. Induction of quinone reductase (QR) activity, a biomarker for anti-carcinogenesis, was significantly increased by the extracts from the leaf tissue of these two cultivars. Extracts of apical leaf tissues had greater MeJA mediated increases in phenolics, glucosinolate concentrations, GS hydrolysis products, and QR activity than extracts from basal leaf tissue samples. The concentration of the hydrolysis product of glucoraphanin, sulforphane was significantly increased in apical leaf tissue of the cultivar ‘Red Winter’ in both 2010 and 2011. There was interaction between exogenous MeJA treatment and environmental conditions to induce endogenous JA. Correlation analysis revealed that indole-3-carbanol (I3C) generated from the hydrolysis of glucobrassicin significantly correlated with QR activity (r = 0.800, P<0.001). Concentrations required to double the specific QR activity (CD values) of I3C was calculated at 230 µM, which is considerably weaker at induction than other isothiocyanates like sulforphane. To confirm relationships between GS hydrolysis products and QR activity, a range of concentrations of MeJA sprays were applied to kale leaf tissues of both cultivars in 2011. Correlation analysis of these results indicated that sulforaphane, NI3C, neoascorbigen, I3C, and diindolylmethane were all significantly correlated with QR activity. Thus, increased QR activity may be due to combined increases in phenolics (quercetin and kaempferol) and GS hydrolysis product concentrations rather than by individual products alone.

Lead heavy metal toxicity induced changes on growth and antioxidative enzymes level in water hyacinths [Eichhornia crassipes (Mart.)

BackgroundLead (Pb) heavy metal pollution in water bodies is one of the serious problems across the world. This study was designed to find out the effect of Pb toxicity on physiological and biochemical changes in Eichhornia crassipes (water hyacinth) seedlings.ResultsThe plant growth was significantly inhibited (50%) at 1000 mg/L Pb concentration. Accumulation of Pb was higher in root than in shoot tissues. The maximum level of Pb accumulation was noticed in roots (5.45%) followed by petiole (2.72%) and leaf tissues (0.66%). Increasing the Pb concentration gradually decreased the chlorophyll content. Intracellular distribution of Pb was also studied using SEM-EDX, where the Pb deposition was observed in both root and leaf tissues. MDA content increased in both the leaf and root tissues up to the 400 mg/L Pb treatment and slightly decreased at higher concentrations. The activity of antioxidative enzymes, such as APX and POX, positively correlated with Pb treatment, while in the case of SOD and CAT enzymes increased up to 800 mg/L treatment and then slightly decreased at higher concentration in both leaf and root tissues.ConclusionsThese results suggest that water hyacinth plants have efficient mechanism to tolerate Pb toxicity, as evidenced by an increased level of antioxidative enzymes. Results clearly indicate that water hyacinth is a feasible plant for hyperaccumulation of heavy metals from polluted wetlands.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0054-6) contains supplementary material, which is available to authorized users.

Creeping Bentgrass Field Response to Pigment‐Containing Products

Reducing summer stress on creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.)] putting greens is a major goal of many turf managers. Use of colorants and pigment‐containing products has been proposed as a means of protecting the plant from environmental stress, especially on bentgrass putting greens grown in heat‐stressed environments. The objective of this research was to investigate the physiological effects of four pigment‐containing products–a combination of zinc oxide (ZnO), green pigment, and titanium dioxide (TiO2) (TurfScreen); Cu‐based pigments (PAR and Foursome); and a Cu‐pigmented paint designed to provide green color to dormant turfgrass in winter months–have on creeping bentgrass under stressful field conditions. Products were applied weekly for 10 wk to two separate studies repeated in time. TurfScreen, PAR, Foursome, and paint all lowered carbon dioxide exchange rate (CER), reduced normalized difference vegetation index (NDVI), and raised canopy temperature relative to nontreated controls. Only paint lowered visual quality and percent turf cover compared to the untreated controls. TurfScreen reduced evapotranspiration (ET) in one of two studies. Root mass was unaffected by any treatment. Zinc (∼800 mg kg−1) and Cu (&gt;155 mg kg−1) concentrations in leaf tissue and soil increased dramatically after TurfScreen and paint application, respectively, and potential toxicity should be considered during long‐term use of these products. The products tested failed to enhance physiological processes normally associated with improved turf health and quality.