Improved Biomass Production Research Articles

Bioregulators Can Improve Biomass Production, Photosynthetic Efficiency, and Ornamental Quality of Gazania rigens L.

Gazania rigens L. is a perennial herbaceous plant that belongs to the Asteraceae family, widely used as bedding or ornamental potted plants. The environmental and economic sustainability of ornamental production can be enhanced using environmentally friendly bioregulators. A pot experiment was conducted to evaluate the influence of key bioregulators gibberellic acid ((GA3) at 50, 100 or 150 mg L−1), humic acid ((HA) at 100, 300 or 600 mg L−1), and ascorbic acid ((AA) at 50, 100 or 200 mg L−1)), on the growth, leaf gas exchange, and ornamental quality of G. rigens. The results indicated that plants treated with foliar applications of GA3, HA, or AA exhibited higher plant fresh and dry biomass, plant height, leaf area, and leaf area ratio, root-shoot ratio, root-shoot mass fractions, and number of flowers, as well as the flowers display time. All bioregulator treatments enhanced the vegetative and floral characteristics of Gazania plants. The GA3 was the most efficient at the concentration of 100 mg L−1. The highest efficacy of HA and AA treatments was observed at the higher concentrations, 600 and 200 mg L−1, respectively. These results were associated with higher photosynthetic rate (A), transpiration rate (E) as well as stomatal conductance (gs), and water use efficiency (WUE). In conclusion, the results suggest that foliar-applied bioregulators to Gazania are promising and represent sustainable strategies to enhance growth, flowering, and flower display time of Gazania plants.

Functional diversity of cover crop mixtures enhances biomass yield and weed suppression in a Mediterranean agroecosystem

SummaryFunctional diversity of cover crop mixtures is thought to improve biomass production and weed suppression, two key agroecosystem services in organic systems. To test this hypothesis, we selected eight cover crop species belonging to four functional groups: (i) vining growing large‐seeded legumes (field pea, common vetch), (ii) erect growing small‐seeded legumes (crimson clover, squarrosum clover), (iii) grasses (barley, oats) and (iv) Brassicaceae (radish, black mustard). Nine cover crop mixtures were designed to create a gradient of diversity in terms of number of species and number of functional groups. A control treatment and all monocrops were included in the trial. Regarding cover crop biomass, mixtures outyielded monocrops by an average of 37%. Both functional identity and composition (i.e. trait complementarity) influenced biomass production and weed suppression provided by cover crops. Regression analysis showed that increase in both species diversity and functional diversity in cover crop mixtures improved the provision of agroecosystem services. Results from this study show that complementarity of species functional traits in cover crop mixtures can be used as a strategy to ensure high biomass production and good weed suppression in changing agroecosystems.

Algae as green energy reserve: Technological outlook on biofuel production.

Depletion of fossil fuel sources and their emissions have triggered a vigorous research in finding alternative and renewable energy sources. In this regard, algae are being exploited as a third generation feedstock for the production of biofuels such as bioethanol, biodiesel, biogas, and biohydrogen. However, algal based biofuel does not reach successful peak due to the higher cost issues in cultivation, harvesting and extraction steps. Therefore, this review presents an extensive detail of deriving biofuels from algal biomass starting from various algae cultivation systems like raceway pond and photobioreactors and its bottlenecks. Evolution of biofuel feedstocks from edible oils to algae have been addressed in the initial section of the manuscript to provide insights on the different generation of biofuel. Different configuration of photobioreactor systems used to reduce contamination risk and improve biomass productivity were extensively discussed. Photobioreactor performance greatly relies on the conditions under which it is operated. Hence, the importance of such conditions alike temperature, light intensity, inoculum size, CO2, nutrient concentration, and mixing in bioreactor performance have been described. As the lipid is the main component in biodiesel production, several pretreatment methods such as physical, chemical and biological for disrupting cell membrane to extract lipid were comprehensively reviewed and presented. This review article had put forth the recent advancement in the pretreatment methods like hydrothermal processing of algal biomasses using acid or alkali. Eventually, challenges and future dimensions in algal cultivation and pretreatment process were discussed in detail for making an economically viable algal biofuel.

Ecological, biophysical and production effects of incorporating rest into grazing regimes: A global meta‐analysis

Abstract Grazing can have considerable ecological impacts when managed inappropriately, however livestock production is a significant contributor to global food security and the removal of land from production is not always a viable option. Grazing management practices that incorporate periods of planned rest (i.e. strategic‐rest grazing) may be an alternative to grazing exclusion or continuous grazing that could achieve ecological and animal production outcomes simultaneously. We conducted a meta‐analysis of global literature to investigate how strategic‐rest grazing mediates ecological (i.e., plant richness and diversity), biophysical (plant biomass and ground cover) and production response variables (animal weight gain and animal production per hectare) compared to continuously grazed or ungrazed areas. Overall, total ground cover and animal production per hectare were significantly greater under strategic‐rest grazing than continuous grazing management, but biomass, plant richness, plant diversity and animal weight gain did not differ between grazing treatments. Increasing the length of rest relative to graze time under strategic‐rest grazing was associated with an increase in plant biomass, ground cover, animal weight gain and animal production per hectare when compared to continuous grazing. Synthesis and applications. Understanding both the ecological and animal production trade‐offs associated with different grazing management strategies is essential to make informed decisions about best‐management practices for the world's grazing lands. We show that incorporating periods of rest into grazing regimes improves ground cover and animal production per hectare and that these benefits are more pronounced with increases in the length of time land is rested for. This extended rest also improves biomass production and weight gain compared to continuous grazing systems. Based on these meta‐analyses, we recommend that future research considers the duration of rest compared to graze time in comparisons of grazing systems.

Effects of gluconate on biomass improvement and light stress tolerance of Haematococcus pluvialis in mixotrophic culture

Mixotrophic culture shows great potential for improving microalgal growth. Currently, the complex roles of organic carbon for biomass enhancement in mixotrophic culture remain a topic of investigation. In this study, the green microalgae Haematococcus pluvialis was cultured for biomass production under mixotrophic conditions using a new organic carbon source, sodium gluconate. Experiments feeding H. pluvialis with sodium gluconate, sodium acetate, and ribose were conducted. The best growth performance was achieved with sodium gluconate exposed to high light intensity. With the addition of 2 g/L gluconate, the maximum cell number achieved 2.43 × 106/mL at 105 ± 3 μmol m−2 s−1 light intensity, a five-fold increase over that of heterotrophic culture and 89.8% increase over ribose-fed mixotrophic culture. The maximum dry cell weight was 2.09 g/L with a specific growth rate of 0.48 d−1, an increase of 77.1% over that with optimal ribose conditions. The cellular motility of microalgae was affected by the culture age and light intensity. At lower light intensity (45 ± 3 μmol m−2 s−1), the highest motile cell number was 7.33 × 105/mL with gluconate. Under mixotrophic conditions, the culture with gluconate kept high numbers of motile cells with the increase of light intensity, 3.17 × 105/mL at 105 ± 3 μmol m−2 s−1. Even high light intensity caused decrease in cellular motility, gluconate-fed microalgae still had active cell activity with more motile cells compared with that fed with ribose. Microalgae with gluconate triggered resistant response against high light intensity under mixotrophic conditions. Moreover, H. pluvialis showed great potential in effective photosynthesis with higher chlorophyll content under high light condition. These results indicate that gluconate is an effective organic carbon source for improving biomass productivity, cell activity, and photosynthesis efficiency for H. pluvialis in mixotrophic culture.

Enhanced biomass production and nutrient removal capacity of duckweed via two-step cultivation process with a plant growth-promoting bacterium, Acinetobacter calcoaceticus P23

Plant growth-promoting bacteria (PGPB) are considered a promising tool to improve biomass production and water remediation by the aquatic plant, duckweed; however, no effective methodology is available to utilize PGPB in large hydroponic systems. In this study, we proposed a two-step cultivation process, which comprised of a “colonization step” and a “mass cultivation step,” and examined its efficacy in both bucket-scale and flask-scale cultivation experiments. We showed that in the outdoor bucket-scale experiments using three kinds of environmental water, plants cultured through the two-step cultivation method with the PGPB strain, Acinetobacter calcoaceticus P23, yielded 1.9 to 2.3 times more biomass than the control (without PGPB inoculation). The greater nitrogen and phosphorus removals compared to control were also attained, indicating that this strategy is useful for accelerating nutrient removal by duckweed. Flask-scale experiments using non-sterile pond water revealed that inoculation of strain P23 altered duckweed surface microbial community structures, and the beneficial effects of the inoculated strain P23 could last for 5–10 d. The loss of the duckweed growth-promoting effect was noticeable when the colonization of strain P23 decreased in the plant. These observations suggest that the stable colonization of the plant with PGPB is the key for maintaining the accelerated duckweed growth and nutrient removal in this cultivation method. Overall, our results suggest the possibility of an improved duckweed production using a two-step cultivation process with PGPB.

Design and Bench-Scale Hydrodynamic Testing of Thin-Layer Wavy Photobioreactors

In a thin-volume photobioreactor where a concentrated suspension of microalgae is circulated throughout the established spatial irradiance gradient, microalgal cells experience a time-variable irradiance. Deploying this feature is the most convenient way of obtaining the so-called “flashing light” effect, improving biomass production in high irradiance. This work investigates the light flashing features of sloping wavy photobioreactors, a recently proposed type, by introducing and validating a computational fluid dynamics (CFD) model. Two characteristic flow zones (straight top-to-bottom stream and local recirculation stream), both effective toward light flashing, have been found and characterized: a recirculation-induced frequency of 3.7 Hz and straight flow-induced frequency of 5.6 Hz were estimated. If the channel slope is increased, the recirculation area becomes less stable while the recirculation frequency is nearly constant with flow rate. The validated CFD model is a mighty tool that could be reliably used to further increase the flashing frequency by optimizing the design, dimensions, installation, and operational parameters of the sloping wavy photobioreactor.

Linear estimators of biomass yield maps for improved biomass supply chain optimisation

Given the need to shift away from fossil fuels, expanding the role of the bioeconomy is vitally important. Biomass supply chain optimisation is a tool that has been used to help the biomass industry gain a foothold. Biomass supply chain models frequently use the average biomass yield of large areas to calculate overall yield. However, there can be large variation in the biomass yield within those areas, losing useful information. A biomass supply chain optimisation framework has been developed which uses information about the quality of land available by incorporating piecewise linear approximation of the biomass yield distribution into the optimisation. Linear approximations of the biomass yield variability allows the supply chain optimisation model to make more accurate decisions about quantity and location of biomass growth operations, affecting all downstream decisions. A case study of southwest Hungary for potential biomass industry viability has been examined using the framework to illustrate the impact of this yield information in the optimisation. The proposed framework successfully optimised the supply chain while accounting for variability in a spatially distributed resource, found that using the biomass yield estimates reduced the overall land usage by up to 17% in some cases, and improved biomass production by over 7%. Further, it improved biomass output, increasing the quantity of bioproducts which can be produced, and increasing the financial performance, thus demonstrating the importance of including yield variability in the optimisation. This framework could be used for other spatially distributed resources, such as solar insolation or wind availability.

Metabolic Profiling and Cold-Starvation Stress Response of Oxygen-Tolerant Lactobacillus gasseri Strains Cultured in Batch Bioreactor.

Phenotypic and genotypic evidence indicates that many LAB strains can grow in presence of oxygen and can shift from fermentative to aerobic and/or respiratory metabolism. The aerobic and respiratory growth of several LAB species have been studied, allowing the selection of strains showing improved biomass production, long-term survival, and resistance under oxygen and stress conditions. The aim of this work was to observe the adaptation of two Lactobacillus gasseri strains, described in a previous work, to aerobic (air injection) and respiratory (air injection plus hemin and menaquionone) conditions obtained in a batch bioreactor. One strain showed the higher biomass production and oxygen consumption as well as the lower acidification in respiratory condition. Instead, the other one grew better in aerobic condition, even though the higher resistance to cold-starvation stress was registered in respiratory condition. In silico analysis revealed notable differences between AL3 and AL5 genomes and that of the type strain. This work contributes to understanding the adaptation response of lactobacilli to aerobic and respiratory metabolism. We demonstrated that the supposed activation of respiratory metabolism may provide several modifications to cell physiology. These features may be relevant in some technological and health-promoting applications, including starter and probiotic formulations.

Model exploration of interactions between algal functional diversity and productivity in chemostats to represent open ponds systems across climate gradients

Eukaryotic microalgae and prokaryotic cyanobacteria (often collectively described as algae) have been proposed as a promising commercially viable feedstock for biofuels and other bioproducts. Open pond algal monocultures are subjected to environmental fluctuations (i.e. temperature), limiting productivity as environmental conditions vary. An approach to overcome such limitation is the replacement of monocultures with customized polycultures that leverage diversity-productivity relationships by exploiting complementary but uninhabited ecological niches. Defining ecological niche complementarity requires an understanding of how traits and trade-offs interact across environmental gradients and for this reason numerical models represent valuable tools to explore the possible solution space prior to experimental design and verification. We have developed a trait-based, dynamic energy budget model (TB-DEB) of microalgal monocultures and polycultures, and simulated the growth of random and customized polycultures under environmental conditions (i.e. temperature, photoperiod) similar to those in operational algal ponds across the US. Each of the algal species selected as a polyculture component is defined by distinct combinations of literature-derived traits related to substrate uptake, light utilization and temperature optima. Members of the polycultures were categorized into algal functional guilds that were defined based on the interaction between thermal traits and pond thermal regimes. When compared to guilds defined by taxonomy, we demonstrate that grouping algal guilds by functional traits can be an effective approach towards improving biomass productivity in operational algal ponds. Simulations show that a polyculture represents the equivalent of a wider niche monoculture, leading to sustained productivity across seasons. Simulations also revealed that higher species diversity and higher functional diversity lead to higher system biomass. In all, results from this modeling study and earlier experimental studies highlight the idea that regardless of the functional group definition, systematic selection of species based on knowledge of physiology, ecology and the environment aiming at maximizing use of niche space through complementarity has positive impacts on system productivity.

Co-cultivation of two freshwater microalgae species to improve biomass productivity and biodiesel production

This study aimed to investigate the symbiotic relationship of two freshwater microalgae species, Ettlia sp. and Chlorella sp. HS-2 to improve biomass productivity. The species were co-cultivated autotrophically under the inoculation ratios (Chlorella/Ettlia) of 1:01, 1:04, 1:08, and 1:16. The performance of co-cultivation was compared with monoculture. It found that the co-cultivation returned higher biomass productivity (P < 0.05) than the monoculture under all inoculation ratios. The highest biomass productivity of 0.70 ± 0.02 g L−1 day−1 was achieved with an inoculation ratio of 1:08. The biomass productivity further increased to 0.74 ± 0.06 g L−1 day−1 by switching the cultivation mode to the mixotrophic condition. The biomass productivity of mixotrophic co-cultivation was higher P < 0.05 (0.74 ± 0.06 g L−1 day−1) than the mixotrophic mono-culture of Ettlia (0.41 ± 0.06 g L−1 day−1) but equal to mixotrophic mono-culture of Chlorella. FACS analysis revealed that the biomass obtained after co-cultivation contained 81% of Chlorella cells. In biochemical composition, co-cultivation (autotrophic) biomass contained protein 41%, carbohydrates 33%, lipids 11%, and pigments 2% of dry cell weight. The major fatty acids produced in the co-cultivation were C16–C18, which are favorable for biodiesel production. It is concluded that the co-cultivation is more favorable than the monoculture to obtain high biomass productivity and stable biomass composition.

Elevated carbon dioxide significantly improves ascorbic acid content, antioxidative properties and restricted biomass production in cruciferous vegetable seedlings

The rise in atmospheric CO2 concentrations has profound impact on nutritional, metabolic and physiological activities of crop plants. In this study, the impact of elevated CO2 ranging from 350 to 4000 ppm on l-ascorbic acid (AsA) content, antioxidative properties and growth characteristics of four cruciferous vegetable seedlings (Chinese cabbage, bok choy, radish and red young radish) was analyzed. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and high performance liquid chromatography (HPLC) analysis showed that elevated CO2 markedly induced AsA biosynthetic and AsA regeneration pathway genes thus accumulating AsA at least 0.53–1.62-folds among seedlings. Subsequent analysis showed that elevated CO2 accumulated relatively more AsA in root vegetables than leafy vegetables. AsA improves the antioxidative properties either directly or indirectly via improving the radical scavenging activities of Super Oxide Dismutase (SOD) in a concentration dependent manner. Additionally, CO2 enrichment activated Ascorbate peroxidase-6 (BrAPX6) to control the accumulation of H2O2. Moreover, CO2 at 700 ppm considerably improved biomass production of Chinese cabbage (1.9%), bok choy (1.84%) and red young radish (3%) seedlings. However, further enrichment of CO2 (1000–4000 ppm) gradually decreased the growth and biomass production (4.91–17.5%) in vegetable seedlings, although it improved AsA content significantly. It is thus apparent that the positive impact of elevated CO2 is restricted to 700 ppm. This study reveals that elevated CO2 can enhance the AsA content significantly, improves antioxidant properties and biomass productions in cruciferous vegetable seedlings in a dose-dependent manner.

Nutritional impact on the biomass yield of Hirsutella citriformis and sporulation on inorganic substrates

ABSTRACTThe Mexican INIFAP-Hir-2 Hirsutella citriformis strain was cultured in six liquid media at different C:N ratios. Glucose and hydrolysed amino acids were used as C and N sources, respectively. During fermentation, low-cost nitrogen sources were used to obtain an improved biomass production, and these cultures were then air-dried, vacuum packed, and evaluated for germination. Cultures containing mycelia were inoculated on different clays to observe spore formation. The highest biomass yield (19.47 g/L) was obtained from the medium supplemented with 36 g/L glucose and hydrolysed casamino acids added at a C:N ratio of 10:1. Furthermore, upon the use of low-cost nitrogen source, the highest dry biomass weights were obtained when cottonseed flour (51.30 g/L) and soybean meal (48.40 g/L) were used. This showed a significant difference with respect to the media supplemented with casamino acids, yeast extract or corn steep powder. Synnemata production on clays was observed only for those cultures grown on soybean meal. Germination and conidia production were evaluated on 8 different clays and diatomaceous earth (Hyflo®). Here, hydrous aluminosilicate (HAS) and montmorillonite (MONT) clay showed a higher percentage of germination, whereas Attapulgite (GA) granulometry −325 y Verge montmorillonite S-140 showed lower germination percentages. Twelve days post inoculation of liquid cultures on various clays, Attapulgite 16/30, HAS 24/48 and Hyflo® showed a higher production of conidia where values reached more than 1 × 107 conidia/g.

Strategy for phytomanagement in an area affected by iron ore dam rupture: A study case in Minas Gerais State, Brazil

In 2015, the Fundão tailing dam collapsed over the district of Bento Rodrigues (Mariana, Minas Gerais, Brazil) causing deaths, hundreds of homeless families and incalculable environmental degradation. Environmentally, economically and socially sustainable strategies are needed for the recovery of the affected areas. The main goal of this study was to evaluate the development, biomass production and toxic mineral elements absorption of three species of aromatic grasses (Chrysopogon zizanioides, Cymbopogon citratus and Cymbopogon winterianus). These three species were planted on polypropylene pots filled with the iron ore tailings collected from the topsoil of the Bento Rodrigues district. The pots were fertilized with increasing doses of organic compost associated with mycorrhizae as a phytomanagement strategy. A 4 × 2 factorial scheme was used. The seedlings were fertilized with four doses of organic compost, with or without mycorrhizae. At the highest dose of the organic compost (2 kg.plant−1), the total dry matter (dry matter of the aerial part + dry matter of the roots) for C. zizanioides was 4.5 times higher than the control (tailing only). For C. winterianus and C. Citratus was 3.8 and 2.8 times higher than the control, respectively. Inoculation with mycorrhizae improved biomass production, especially in C. zizanioides. The Fe and Mn levels found in the aerial part of the plants fertilized with organic compost were lower than those just growing on the iron ore tailings for the three species, which suggest that the organic matter apparently helped the plants in the exclusion of the hazardous substances and therefore increased the tolerance to these adverse environmental conditions. C. zizanioides, associated with organic matter and mycorrhizae, would be the recommended species. The proposed phytomanagement strategy can have a significant contribution to the gradual recovery of the affected area and also serve as a source of income for the local population.

Nannochloropsis gaditana and Dunaliella salina as Feedstock for Biodiesel Production: Lipid Production and Biofuel Quality

Introduction: Microalgal lipids have a wide range of applications, from biodiesel manufacture in the energy industry to the production of polyunsaturated fatty acids for the pharmaceutical industry. Microalgal lipid productivity and quality, however, vary greatly depending on cultivation parameters.&#x0D; Aims: In this study, we investigated the potential of two marine microalgae, Nannochloropsis gaditana and Dunaliella salina, to be used as feedstock for biodiesel production.&#x0D; Methodology: A Taguchi L4 orthogonal array design was applied to understand the effects of sodium acetate (0 or 2 g L−1), sodium bicarbonate (0 or 2 g L−1), and sodium nitrate (25 or 75 mg L−1) concentrations on biomass and lipid productivities. Fatty acid methyl ester (FAME) profiles of microalgal lipids obtained under the best conditions were determined, and FAME results were used to predict biodiesel properties.&#x0D; Results: Both carbon sources (sodium acetate and sodium bicarbonate) improved biomass productivity. Lipid productivity was enhanced only by sodium acetate. The highest lipid productivities obtained were 10.25 ± 1.02 and 12.12 ± 0.28 mg L−1 day−1 for N. gaditana and D. salina, respectively. Palmitic (C16:0), stearic (C18:1), oleic (C18:1), linoleic (C18:2), lauric (C12:0), and myristic (C14:0) acids were the major components of D. salina oil. The major fatty acids in N. gaditana oil were C16:0, C18:0, and C18:1.&#x0D; Conclusion: The great differences in FAME profiles resulted in different biodiesel properties. Biodiesel from N. gaditana oil was predicted to have a higher cetane number (73.20) than that derived from D. salina oil (59.59). D. salina oil biodiesel, however, was predicted to have better properties than N. gaditana oil biodiesel, including lower cloud point (0.46°C) and cold filter plugging point (−7.27°C).

Body Mass Increase Induced by Eight Years of Artificial Selection in the Yellow Mealworm (Coleoptera: Tenebrionidae) and Life History Trade-offs.

Efforts to improve rearing conditions of Tenebrio molitor L. (Coleoptera: Tenebrionidae) for insect biomass production included selecting for larger size pupae. The effects of an 8-yr continuous selection of T. molitor pupae for larger size were studied. Data consisting of daily counts and weights of pupae were analyzed using regression to determine the effects of selection over time. A preliminary evaluation of food conversion, growth, fecundity, and larval survival was done to compare ancestral versus selected strains. A significant positive correlation was identified between pupal size and time indicating a significant increase in pupal size over time in the selected T. molitor strain. A preliminary comparison of ancestral and selected strains showed significantly larger pupal size, growth rate, fecundity, and efficiency of conversion of ingested food in the selected strain. However, the selected strain also showed significantly lower larval survival than the ancestral strain. The low larval survival impacted the overall productivity of the selected strain resulting in no significant differences in biomass production when compared with the ancestral strain. The potential of using selection to improve biomass productivity in T. molitor is discussed.

Selenium enhanced phytoremediation of diesel contaminated soil by Alternanthera philoxeroides

Using a 60-day pot culture experiment, we investigated the effect of selenium on phytoremediation of soil containing high-level diesel by Alternanthera philoxeroides (alligator weed). Diesel (20 g kg−1) decreased the growth of A. philoxeroides and induced oxidative stress, as indicated by tissue levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Adding Se (0.5 or 1.5 mg kg−1) to diesel-treated soil alleviated oxidative stress and improved biomass production, and the low dose was as effective as the high dose. After 60 days, the reduction in rhizospheric soil diesel was 20.1 ± 0.55% without Se and 35.2 ± 3.6% with Se, showing a significant increase in efficiency. Again, the low Se dose was as effective as the high dose. These findings advance the field phytoremediation by demonstrating that Se, at 0.5 mg kg−1, enhances removal and increases plant tolerance to petroleum hydrocarbons.

Biomass Accumulation and Cell Wall Structure of Rice Plants Overexpressing a Dirigent-Jacalin of Sugarcane (ShDJ) Under Varying Conditions of Water Availability

A sugarcane gene encoding a dirigent-jacalin, ShDJ, was induced under drought stress. To elucidate its biological function, we integrated a ShDJ-overexpression construction into the rice Nipponbare genome via Agrobacterium-mediated transformation. Two transgenic lines with a single copy gene in T0 were selected and evaluated in both the T1 and T4 generations. Transgenic lines had drastically improved survival rate under water deficit conditions, at rates close to 100%, while WT did not survive. Besides, transgenic lines had improved biomass production and higher tillering under water deficit conditions compared with WT plants. Reduced pectin and hemicellulose contents were observed in transgenic lines compared with wild-type plants under both well-watered and water deficit conditions, whereas cellulose content was unchanged in line #17 and reduced in line #29 under conditions of low water availability. Changes in lignin content under water deficit were only observed in line #17. However, improvements in saccharification were found in both transgenic lines along with changes in the expression of OsNTS1/2 and OsMYB58/63 secondary cell wall biosynthesis genes. ShDJ-overexpression up-regulated the expression of the OsbZIP23, OsGRAS23, OsP5CS, and OsLea3 genes in rice stems under well-watered conditions. Taken together, our data suggest that ShDJ has the potential for improving drought tolerance, plant biomass accumulation, and saccharification efficiency.

Effects of Mixed Planting of Horizontal- and Erect-Leafed Varieties on Canopy Light Use and Growth in Sugarcane

Improving sugarcane canopy structure using varietal mixtures, by exploiting the diversity of plant types available, is effective for improving biomass production and cane yield. A single variety cannot meet the demands for optimal canopy structure at each growth stage and for adaptability to changing within- and above-canopy light environments. The present study performed mixed planting of two varieties with different plant types to demonstrate the effects of such a mixture on canopy growth and its light use in simulated canopy conditions at the early growth stage. The varietal mixture induced plasticity of plant size, leaf allocation, and nitrogen accumulation, and altered the growth habit of each variety compared with that when each was grown as a monocrop. Mixed-variety planting increased the plant size of the erect-leafed variety while decreasing that of the horizontal-leafed variety; however, the total canopy biomass of the mixture was greater than the one predicted on the basis of the two-component monocropped ones. Leaves of the erect-leafed variety were distributed at a higher canopy layer, whereas those of the horizontal-leafed variety were distributed at a lower canopy layer under mixed planting than under the monocrops. Through such habitat segregation, lower light extinction coefficients were obtained with the moderate leaf area index of the mixture.

External application of NADPH enhances biomass accumulation, seed germination and modulates expression of oxidative pentose phosphate pathway genes in Arabidopsis

NADPH is one of the main reducing powers in plant cells. It plays important roles as cofactor or reductant and is involved in a wide range of anabolic pathways and thus may influence plant growth and development. The present study was conducted with the objective to analyse the effect of NADPH on plant growth and development when applied externally. External application of 10 µM and 30 µM NADPH resulted in 198% and 258%, increase in biomass of Arabidopsis thaliana plants, respectively. Under normal photoperiod of 16 h, 24% increase in seed germination was observed in 10 µM as well as 30 µM NADPH treated seeds on day 8 of the seed sowing. Further, targeted transcriptome profiling of all the eight genes encoding enzymes of oxidative pentose phosphate pathway revealed the differential expression of these genes under light and dark in response to NADPH. Interestingly, expression of glucose-6-phosphate-1-dehydrogenase and 6-phosphogluconolactonase, the first two enzymes of oxidative pentose phosphate pathway was up-regulated many fold under dark, whereas, NADPH treatment significantly increased the expression of the 2nd (6-phosphogluconolactonase) and 3rd gene (6-phosphogluconate dehydrogenase) of oxidative pentose phosphate pathway during light period. Proteomic analysis revealed thirty five proteins expressing differentially in response to NADPH treatment. These differentially expressed proteins were found to be involved in various biological processes. To the best of our knowledge this is the first report about the effect of external application of NADPH on plant biomass and seed germination. The information generated in the present study may be useful in having better insights into the role and influence of NADPH on plant growth and development and may provide platform to devise NADPH associated strategies for improving biomass production of useful plants.