Longer Internodes Research Articles

Yield and Multivariate Analysis among Twelve Sugarcane (Saccharum Officinarum L) Genotypes at Mankusa, North Western, Ethiopia

Smallholders cultivated sugarcane for household consumption, immediate cash, and feeding livestock in Ethiopia. However, its production and productivity are constrained by a lack of improved varieties. Sugarcane germplasm was collected from Districts of West Gojjam, Ethiopia, to evaluate yield and its contributing characters and quantify the phenotypic diversity at Mankusa, Jabitehnan, Ethiopia. The experiment was conducted using a randomised complete block design with three replications for two crop cycles, from April 2020 to March 2023. Data were recorded for the number of tillers, internode length, sellable stalks, plant height, stalk diameter, cane yield and biomass yield from twelve genotypes collected. The data recorded were subjected to analysis of variance, and means were separated using the Duncan Multiple Range Test at a 5% significance level. Variance and multivariate analysis indicated the existence of high phenotypic diversity between genotypes in all quantitative traits studied. Acc 7/20 and Acc 5/20 genotypes produced the highest number of tillers and longest internodes, while Acc 6/20 produced the highest number of sellable stalks. The genotype Acc 4/20 was the longest, and the thickest genotype, which could be elite donors for it respected quality traits through crossing. The highest cane yield was recorded from Acc 4/20 (178.04 t/ha), Acc 7/20 (151.41 t/ha), Acc 8/20 (134.1 t/ha) and Acc 12/20 (132 t/ha), producing 58, 34, 19 and 17% advantageous from the overall genotypes mean, respectively. Cluster analysis grouped the twelve sugarcane genotypes into four clusters, indicating the possibility of broadening the genetic basis by crossing genotypes in the different clusters. It also indicated that a cross between cluster II and III genotypes could create the thickest canes with many sellable stalks. Therefore, genotypes Acc 04/20, Acc 07/20, Acc 8/20 and Acc 12/20 have been recommended and must be evaluated in other sugarcane growing areas to exploit their potential.

The red/far-red light photoreceptor FvePhyB regulates tissue elongation and anthocyanin accumulation in woodland strawberry.

Light is an important environmental signal that influences plant growth and development. Among the photoreceptors, phytochromes can sense red/far-red light to coordinate various biological processes. However, their functions in strawberry are not yet known. In this study, we identified an EMS mutant, named P8, in woodland strawberry (Fragaria vesca) that showed greatly increased plant height and reduced anthocyanin content. Mapping-by-sequencing revealed that the causal mutation in FvePhyB leads to premature termination of translation. The light treatment assay revealed that FvePhyB is a bona fide red/far-red light photoreceptor, as it specifically inhibits hypocotyl length under red light. Transcriptome analysis showed that the FvePhyB mutation affects the expression levels of genes involved in hormone synthesis and signaling and anthocyanin biosynthesis in petioles and fruits. The srl mutant with a longer internode is caused by a mutation in the DELLA gene FveRGA1 (Repressor of GA1) in the gibberellin pathway. We found that the P8 srl double mutant has much longer internodes than srl, suggesting a synergistic role of FvePhyB and FveRGA1 in this process. Taken together, these results demonstrate the important role of FvePhyB in regulating plant architecture and anthocyanin content in woodland strawberry.

Pedicularis rostratospicata subsp. marsica (P. Sect. Rostratae, Orobanchaceae), a New Subspecies from the Central Apennines (Italy).

The new subspecies Pedicularis rostratospicata subsp. marsica is here described based on morphological and molecular analyses. The new taxon is endemic to few localities of the Central Apennines within the Abruzzo, Lazio and Molise National Park (Central Italy). Pedicularis rostratospicata subsp. marsica can be distinguished from the other two currently accepted subspecies (subsp. rostratospicata and subsp. helvetica) by their taller stems, shorter petioles of basal and middle leaves, narrower blades of basal leaves, longer inflorescences with longer internodes and more flowers, and longer calyx lobes. Molecular analysis confirmed the autonomy of the new taxon. Furthermore, the conservation status assessment of the new subspecies according to IUCN categories and criteria is proposed and discussed, and an analytical key to the three subspecies of P. rostratospicata is presented.

Effect of prohexadione-calcium onphotosynthetic and yield parameters in basmati rice (Oryza sativa L.) against lodging stress

Basmati rice cultivators with longer internodes and shallow rooting system are prone to lodging especially during panicle development thus ultimately reducing yield, quality as well as efficiency of mechanical harvesting.Manipulation of GA status both via using exogenous application of GA or use of GA biosynthesis inhibitors or either by genetic alteration are regularly used to optimize plant growth and yields. Keeping this in mind the main objective of the study was to assess the role of Prohexadione-calcium (Pro-Ca) to reduce internode elongation against lodging stress without negatively affecting its productivity. A field experiment was conducted on three cultivars of basmati rice (Punjab Basmati 2, Punjab Basmati 3 and Pusa Basmati 1121) in split plot design at three concentration levels (foliar application) of Pro-Ca @5,10 and 20mg/l at vegetative and anthesis stage. Pro-Ca was found to uphill the concentrations of total chlorophyll (~9%)and Carotenoid(~4%) content in leaves at both vegetative and anthesis stages. An increment in the photosynthetic rate in flag leaf was also recorded in Pro-Ca treated sets in comparison to control, A significant increase in sucrose content in fully expanded leaf at vegetative and flag leaf at anthesis stage was recorded.Plant height significantly decreased in Pro-Ca treated plants and this decrease in height was recorded more with increased concentration of Pro-Ca. The increase in the yield contributing parameters viz., number of spikes/plant and grain/m2might be attributed to the blockage of gibberellins synthesis on account of Pro-Ca applicationin selected basmati rice variety PUSA 1121 by upregulating the photosynthetic rate (2%) andalso increase in sucrose content(2 to 18%).

Morphological characterization of maize genotypes in Sylhet

Maize plays an important role both as food and feed throughout the world. For morphological characterization and evaluation of yield attributes of maize genotypes an experiment was carried out at the experimental field of the Department of Crop Botany and Tea Production Technology, Sylhet Agricultural University (SAU). The experimental materials were seven exotic maize genotypes viz.ZM 0001, ZM 0002, ZM 0003, ZM 0004, ZM 0005, ZM 0006ZM 0007 along with BARI Maize 6 as control. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Significant variations were observed among eight maize genotypes for most of the plant characters studied. The tallest plant was found in ZM 0005(246.5 cm). The highest number of leaves was produced in ZM 0001 (14.01). The longest and widest leaf was recorded in ZM 0004 (94.67 cm) and BARI Maize 6 (10.32 cm), respectively. The longest internode was found in ZM 0004 and ZM 0005 (21.61 cm). The genotype ZM 0004 was the earliest in respect of tasseling and silking. Ear height was highest in ZM 0005 (143.8 cm). The genotype ZM 0004 matured the earliest (109.3 days) while BARI Maize 6 matured the last (126 days). No variation was found for ear shape but in terms of kernel color, kernel type, kernel row arrangement and shape of upper surface of the kernel there were great variations among the genotypes. BARI Maize 6 produced the largest kernel with the highest thousand kernel weight. Grain yield plant-1 t ha-1 was highest in BARI Maize 6 which was closely followed by ZM 0005 and ZM 0004 among the studied genotypes. A correlation study between the yield and yield contributing characters showed that ear length, ear diameter, number of kernels row-1, kernel length, kernel width, kernel thickness, thousand kernel weights, and the weight of kernels ear-1, prolificacy index and weight of kernels plant-1 had a significant positive correlation with grain yield. Vol. 10, No. 1, April 2023: 21-32

The Effect of Alkaline Treatment On the Schizostachyum Grande Fibre for Textile Applications

Among commercial Malaysian bamboo species, Schizostachyum Grandespecies are characterised by their longest internode and thinner culm wall, which allow more attainable fibres during the extraction process. However, the chemical composition of bamboo fibres is higher than any other natural fibre, resulting in coarse and stiff fibres that require alkaline treatment to develop fine fibres. This paper presents the effect of alkaline treatment concentration and soaking time on the physical properties and tensile properties of bamboo fibres. The bamboo fibre was treated with an alkaline solution at 4 and 8 wt.% concentration for 6, 12, 18, and 24 hours. The diameter and fineness of bamboo fibre wereevaluated to determine if alkaline concentration and soaking time affected the fibres. Results showed that the treated fibre diameter decreased by 23.2% to 66.51μm at 8 wt.% alkaline concentrationsfor 12 hours of soaking timecompared to the untreated bamboo fibre of 86.56μm.The fibre fineness of 11.96 tex was produced at 24 hours of soaking time and8 wt.% alkaline concentrations. Alkaline treatment was effective in causing a decrease in fibre diameter and produced the finest fibre. Thinner and finer fibre was produced as alkaline concentration and soaking time increased.The highest tensile strength of treated bamboo fibre was 1.42 GPa at a 4 wt% alkaline concentration and6 hours of soaking time. Elongation at break and tenacity improved remarkably when the alkaline concentration and soaking time were increased, which were 3.11% and 45 cN/Tex, respectively, at 8 wt% alkaline concentrationsfor 12 hours of soaking time. Moreover, the 8 wt% alkaline concentration was the best for bamboo fibre because the treatment was effective in causing a decrease in fibre diameter and produced the finest fibre. The elongation at break and tenacity of fibres were also improved at 12 hours of soaking time. The tensile strength and modulus of fibre were reduced at longer soaking times at high alkaline concentrations of more than 18 hours.

Addition of green light improves fruit weight and dry matter content in sweet pepper due to greater light penetration within the canopy

The use of artificial light to supplement natural light is essential for successful greenhouse winter production in regions with low natural sunlight to meet the increasing consumer demand for fresh vegetables. Traditionally, high-pressure sodium lights have been used. However, light-emitting diodes (LEDs) are receiving substantial interests as they have higher photon efficacy and allow for spectral manipulation. There has been a lot of research on red and blue LED light but green light has not been studied to the same extent due to its perceived lower photosynthetic efficiency. However, green light can penetrate deep into canopy and thus could improve light intensity and photosynthesis deep within canopy. Therefore, we investigated the response of sweet pepper (Capsicum annuum) plants cv. ‘Eurix’ and ‘Gina’ under LED lighting with different percentages of green light (red/blue with 0 (control), 12, 24 and 43% green) at a light intensity of 175 µmol m−2 s−1 during a 6-month winter production period in Ontario, Canada. Gina plants grown under 12% green light had longer internodes than those grown under a red/blue control. The tenth leaves of Eurix plants grown under all green light treatments had higher chlorophyll value than the red/blue control. Leaves of both cultivars grown under the green light treatments tended to have slightly higher photosynthetic rates. The fruit weight (g fruit−1) increased by 2–15% depending on cultivars and percentages of green light, and fruit dry matter content linearly increased with increasing percentages of green light. Notably, the light intensity deep within the canopy (3 m from the tip) in treatments with green light was 43–158% higher. Thus, the increased light deep within the canopy with the green light treatments improved pepper fruit weight and dry matter content through increased photosynthesis and carbon export.

Light intensity can be used to modify the growth and morphological characteristics of cannabis during the vegetative stage of indoor production

Although the vegetative stage of indoor cannabis (Cannabis sativa) production can be relatively short in duration, there is a high energy demand due to higher light intensities (LI) than the clonal propagation stage and longer photoperiods than the flowering stage (i.e., ≥ 16 vs. 12 h). While electric lighting is a major component of both energy consumption and overall production costs, there is a lack of scientific information to guide cultivators in selecting a LI that corresponds to their vegetative stage production strategies. To determine the vegetative plant responses to LI, clonal plants of ‘Gelato’ (indica-dominant hybrid genotype) were grown for 21 days with canopy-level photosynthetic photon flux densities (PPFD) ranging between 135 and 1430 µmol·m−2·s−1 with a 16-h photoperiod (i.e., daily light integrals of 7.8–82.4 mol·m−2·d−1). Plant height and growth index (i.e., a canopy volume metric) responded quadratically; the number of nodes, stem thickness, and aboveground dry weight increased asymptotically; and internode length and water content of aboveground tissues decreased linearly with increasing LI. Foliar attributes had varying responses to LI. Chlorophyll content index (i.e., SPAD value) increased asymptotically, leaf size decreased linearly and specific leaf weight increased linearly with increasing LI. Generally, PPFD levels of ≈ 900 µmol·m−2·s−1 produced compact, robust plants while PPFD levels of ≈ 600 µmol·m−2·s−1 promoted more open plant architecture (i.e., taller plants with longer internodes), which can increase intra-canopy airflow and may reduce development of potential foliar pests in compact (e.g., indica-dominant) genotypes.

Colchicine induced morphological variability in sugarcane

Mutation breeding is one of the tools in genetic improvement. The existence of morphological differences among the mutants and the original indicates genetic changes in putative mutants. The research aimed to determine morphological characters of sugarcane colchicine-induced putative mutants. The materials were 21 numbers of putative mutants derived from the PS 881 variety as a parent. Morphological traits were observed on a seven-month-old plantation of sugarcane mutants in January 2019 at the UPBUP screen houses. The descriptor list consisted of 34 morphological characters, including leaves, sheath, stalks, internodes, and buds. The results showed that putative mutants have a narrow diversity and separated into two large clusters with a dissimilarity level of 0.25 with PS 881. Cluster I consisted of 11 putative mutants (38B, 14A, 33A, 18A, 4B, 31A, 52A, 4A, 3A, 30A, and 6A) and cluster II consisted of 10 putative mutants (54A, 38A, 37A, 36B, 60A, 49A, 27A, 22B, 17A, and 9A). Several mutants have leaves with darker green color, larger stalk diameter, and longer internode than their parents. Further evaluation needs to be done to identify mutants with high production potential.

Transgenic Chrysanthemum indicum overexpressing cin-miR396a exhibits altered plant development and reduced salt and drought tolerance

The conserved microRNA396 (miR396) is involved in growth, development, and abiotic stress responses in a variety of plants by regulating target genes. Here, we obtained transgenic Chrysanthemum indicum (C. indicum) overexpressing the cin-miR396a gene. The transgenic plants (TGs) had longer internodes and fewer epidermal hairs in contrast with the wild-type (WT) control. cin-miR396a overexpression in C. indicum reduced salt tolerance and drought tolerance. After salt and drought stress compared with WT plants, the transgenic C. indicum exhibited a relative decrease in leaf water content, and the leaf free proline content, also exhibited a relative increase, in the leaf conductivity and leaf Malondialdehyde content, while the total chlorophyll content did not differ significantly from WT, and the Na+/K+ ratio in the roots of transgenic C. indicum increased after salt stress. We also identified two target genes of cin-miR396a, CiGRF1 and CiGRF5, whose expression was induced by salt and drought treatments and suppressed in transgenic C. indicum. Taken together, our results reveal a unique role for the regulatory module of miR396a-GRFs in C. indicum development and response to abiotic stresses. cin-miR396a plays a negative regulatory role in C. indicum in response to salt and drought stresses.

In Vitro Induction and Characterization of Polyploid Hydrangea macrophylla and H. serrata

Hydrangea macrophylla (Thunb.) Ser. and H. serrata (Thunb.) Ser. are popular and commercially important landscape and floriculture crops. Although both species are typically diploid, induced polyploids often exhibit horticulturally valuable traits. Procedures for inducing polyploidy vary by species and often have low or inconsistent efficacy. In this study, oryzalin and nitrotyrosine were investigated as in vitro mitotic inhibitors for inducing polyploidy in H. macrophylla ‘Robert’ and H. serrata ‘MAK20’. First, shoot apices of ‘MAK20’ were treated with 15 μm oryzalin for 0, 2, 4, 6, or 8 days, and the ploidy of shoots was determined after 8 weeks. A regression analysis showed that the proportion of polyploids (tetraploid plus mixoploid shoots) increased with the exposure duration. During a follow-up experiment, ‘MAK20’ and ‘Robert’ were treated with oryzalin (0 or 15 μm) and nitrotyrosine (0, 25, 50, and 100 µm for ‘MAK20’ and 0, 12.5, 25, 50, and 100 µm for ‘Robert’) in a factorial treatment arrangement. Oryzalin, nitrotyrosine, and their interaction influenced polyploid frequency for ‘Robert’, whereby the combination of oryzalin (15 μm) and nitrotyrosine (50 μm) resulted in the highest polyploid induction of 50%. Oryzalin influenced polyploid frequency for ‘MAK20’ ( = 30.4%), but not nitrotyrosine or the interaction between nitrotyrosine and oryzalin. Morphology and pollen germination of these autotetraploid ‘Robert’, ‘MAK20’, and previously developed autotetraploid H. macrophylla ‘David Ramsey’ plants were compared with their diploid counterparts 1 year after plants were moved ex vitro. Compared with diploids, tetraploid hydrangeas had larger leaves, thicker stems, lower leaf area/fresh weight ratios, and longer internodes. Although all tetraploids exhibited fewer inflorescences per plant, both H. macrophylla cultivars had larger inflorescence diameters and ‘David Ramsey’ had a greater number of showy florets (sterile florets with enlarged, decorative sepals) per inflorescence. Sepal colors were compared using International Commission on Illumination L*a*b* color space. Tetraploid ‘MAK20’ had lower L* values (darker sepals), and tetraploid ‘Robert’ and ‘MAK20’ both had higher a* values (redder sepals). Pollen germination rates were greatly reduced in all tetraploid lines, but they retained some viability. These results provide an effective protocol for in vitro polyploid induction of Hydrangea sp. and documented certain desirable traits associated with tetraploid phenotypes.

Physiological and transcriptomic responses of Mikania micrantha stem to shading yield novel insights into its invasiveness

The rapid stem elongation of the invasive weed Mikania micrantha in the forest understory is of vital significance for its successful invasion. To understand the physiological and molecular mechanisms for this process, here we comparatively investigated the physiological characteristics and transcriptome patterns of M. micrantha stem under low light (30%) and full light (100%) conditions. The results showed that M. micrantha stem had photosynthetic capacity, which was highly plastic to light intensities, constituting an indispensable part of the plastic response of M. micrantha to shading. M. micrantha had longer internodes, epidermal cells, and consequently longer stems under low light than full light conditions, which could proximally be attributed to phytohormone production and reduction of photoprotective substances as potential metabolic trade-off, as observed here under shading treatment. The transcriptome sequencing and qPCR verified the results from physiological investigation, and showed that under low light condition the expression levels of genes involved in photosynthesis (e.g. MmPsaA, MmPsbO1 and MmFd3) were generally down-regulated in comparison to full light condition, as were genes related to the photoprotective substances synthesis (e.g. MmCHS, and MmF3H1) and the negative regulators of phytohormone (e.g. MmAUX1, MmRR1 and MmGAI). It was concluded that the regulation of phytohormones and photoprotective substances are important material basis for the rapid elongation of M. micrantha stems with high plasticity, which facilitates the vine's invasiveness in the forest understory.

Myelination of parvalbumin interneurons shapes the function of cortical sensory inhibitory circuits

Myelination of projection neurons by oligodendrocytes is key to optimize action potential conduction over long distances. However, a large fraction of myelin enwraps the axons of parvalbumin-positive fast-spiking interneurons (FSI), exclusively involved in local cortical circuits. Whether FSI myelination contributes to the fine‐tuning of intracortical networks is unknown. Here we demonstrate that FSI myelination is required for the establishment and maintenance of the powerful FSI-mediated feedforward inhibition of cortical sensory circuits. The disruption of GABAergic synaptic signaling of oligodendrocyte precursor cells prior to myelination onset resulted in severe FSI myelination defects characterized by longer internodes and nodes, aberrant myelination of branch points and proximal axon malformation. Consequently, high-frequency FSI discharges as well as FSI-dependent postsynaptic latencies and strengths of excitatory neurons were reduced. These dysfunctions generated a strong excitation-inhibition imbalance that correlated with whisker-dependent texture discrimination impairments. FSI myelination is therefore critical for the function of mature cortical inhibitory circuits.

Growth Performance of Different Mango (Mangifera indica L.) Varieties as Rootstock for Harumanis Planting Material Production

Mango (Mangifera indica L.) is one of the important crops cultivated in Malaysia. The purpose of this experiment was to evaluate the germination and the growth of selected seedlings from commercially significant mango varieties such as Chokanan, Sala, Harumanis and Masmuda, and also non-commercially significant varieties namely Telur and Epal. The six tested rootstocks were studied for their effect on grafting success, survival and takes growth of Harumanis variety. The results indicated that Telur scored the highest germination percentage with 74.64%, while Harumanis scored the least germination of 30.76%. A maximum stem diameter was observed in Chokanan rootstocks at 13.41 mm, while the minimum value was observed in Harumanis rootstocks with 9.68 mm. For internodes length, Sala had the longest internode with 12.48 cm, while Epal had the shortest with 8.53 cm with the difference of 31.65%. For grafting performance, all tested rootstocks exhibited 100% success (30 days after grafting, DAG) and survival (60 DAG) when grafted with Harumanis scion, with the exception of Sala with 85% survival. At 21 DAG, Telur was observed to have the maximum bud sprouting with 85% while Sala produced the minimum with 30%. For scion growth, Harumanis rootstocks showed the maximum value in terms of scion length and diameter, while Masmuda produced the shortest.

LOMATOGONIUM GAURGOPALII, A NEW SPECIES OF GENTIANACEAE FROM SIKKIM HIMALAYA

Lomatogonium gaurgopalii sp. nov., a new species of Gentianaceae from Sikkim Himalaya, is described and illustrated. It can be distinguished from its morphologically closest relative, Lomatogonium cherukurianum S.K.Dey & D.Maity, mainly by its robust habit, longer internodes, much larger creamy yellow flower and much larger floral parts; the presence of many hairs in an inverted semilunar arrangement behind the filament bases; and its larger, narrowly ovoid to narrowly ellipsoid ovary. Lomatogonium gaurgopalii is also unique in having pollen grains with striate-reticulate exine ornamentation without perforations.

Ailuroglossum (Boraginaceae, Cynoglosseae), a New Genus Endemic to Southern China, and a New Species

A new genus, Ailuroglossum Sutorý (Boraginaceae), endemic to Sichuan and Yunnan provinces of southern China, is described. It includes two species: A. triste (Diels) Sutorý, formerly recognized as Cynoglossum triste Diels, and the newly described A. breviglochidiatum Sutorý. The genus is distinguished from Cynoglossum L. by a combination of characters, including a rhizome rather than a taproot, an almost flat gynobase, narrowly conical style, and discoid stigma, nutlets with perfect separation, without ventral attachment, and hourglass-shaped tricolporate pollen grains. The new species, A. breviglochidiatum, is distinguished by its more slender rhizomes with longer internodes, differently shaped leaves, and smaller nutlets with a denser indument of shorter glochids.

Phenotypic plasticity influences the success of clonal propagation in industrial pharmaceutical Cannabis sativa.

The burgeoning cannabis market requires evidence-based science such that farmers can quickly and efficiently generate new plants. In part, horticultural operations are limited by the success of cloning procedures. Here, we measured the role of environmental conditions and cultivar identity on the success of generating long branch material with many meristems in planting stock (mothers) and in rooting success of stem-derived clones. To evaluate the influence of lighting treatments on the optimal production of branching mothers, four lighting conditions (Fluorescent High Output T5s [T5], Metal halide lamps [MH], Plasma lamps [PL], or Metal halide lamps augmented with far red LED lights [MH+FR]) were applied to two cultivars of container grown plants (Cannabis sativa L. ‘Bubba Kush’, ‘Ghost Train Haze’) grown in peat-based organic substrates in mylar grow tents. To evaluate the influence of lighting, cutting tool (secateurs or scalpels), and stem wounding (present/absent) on optimal rooting of stems, three lighting conditions (Fluorescent T8s, T5, PL) were applied to three cultivars of peat pellet grown plants (C. sativa L. ‘Bubba Kush’, ‘Ghost Train Haze’, ‘Headband’). Mothers grown under T5 and MH (vs MH+FR) produced ~30% more meristems. However, growing mothers under MH+FR were 19% taller than mothers under T5, with ~25% longer internodes on dominant stems than plants under any other lighting condition. Canopies were denser under T5 because petiole length was ~30% shorter under T5 and fan leaves were longer and narrower under MH+FR and MH+FR and PL, respectively, than under other lighting conditions. Cultivar Ghost Train Haze stems rooted most frequently and most quickly. Wounded stems were 162% more likely to root than unwounded stems and rooted 1.5 days earlier. Our results will guide producers attempting to maximize the rate of clone production in licensed facilities; although results may differ among cultivars, where cultivars differed in their average phenotype as mother plants, and their propensity to root from cuttings, and the speed with which they produced those roots.

Overexpression of OsPIL1 enhanced biomass yield and saccharification efficiency in switchgrass

Switchgrass (Panicum virgatum L.) is a herbaceous cellulosic biofuel plant with broad adaptability. However, the intrinsic recalcitrance of biomass and limited land for switchgrass planting hinder its utilization as feedstock for biofuel ethanol production. The OsPIL1 (PHYTOCHROME INTERACTING FACTOR 3-LIKE 1) gene encodes a basic helix-loop-helix transcription factor. Its expression is induced by light, which facilitated the expression of cell wall-related genes, promoted cell elongation and resulted in longer internode in rice. Here, we introduced the OsPIL1 gene into switchgrass by Agrobacterium-mediated transformation with the aim of improving biomass yield of transgenic switchgrass plants. The transgenic plants were verified by PCR, Southern-blotting, RT-PCR and qRT-PCR tests, respectively. The transgenic plants overexpression of OsPIL1 showed increased plant height and biomass yield. Microscopy analysis showed that the length of epidermal cells of transgenic plants was longer than that of wild type. OsPIL1 overexpressed transgenic switchgrass plants also released more soluble sugar after enzymatic hydrolysis, indicating improved saccharification efficiency. The results suggest OsPIL1 can be used as a useful molecular tool in improving plant biomass and saccharification efficiency with the purpose of plant fiber biofuel ethanol production.

Overexpression of a cytosolic NADP+-isocitrate dehydrogenase causes alterations in the vascular development of hybrid poplars.

Cytosolic NADP+-isocitrate dehydrogenase (ICDH) is one of the major enzymes involved in the production of 2-oxoglutarate for amino acid biosynthesis in plants. In most plants studied, ICDH is encoded by either one gene or a small gene family, and the protein sequence has been highly conserved during evolution, suggesting it plays different and essential roles in metabolism and differentiation. To elucidate the role of ICDH in hybrid poplar (Populus tremula x P. alba), transgenic plants overexpressing the Pinus pinaster gene were generated. Overexpression of ICDH resulted in hybrid poplar (Populus tremula × P. alba) trees with higher expression levels of the endogenous ICDH gene and higher enzyme content than control untransformed plants. Transgenic poplars also showed an increased expression of glutamine synthetase (GS1.3), glutamate decarboxylase (GAD) and other genes associated with vascular differentiation. Furthermore, these plants exhibited increased growth in height, longer internodes and enhanced vascular development in young leaves and the apical region of stem. Modifications in amino acid and organic acid content were observed in young leaves of the transgenic lines, suggesting an increased biosynthesis of amino acids for building new structures and also for transport to other sink organs, as expanding leaves or young stems. Taken together, these results support an important role of ICDH in plant growth and vascular development.

The influence of substrate type and chlormequat on the growth and flowering of marigold (Tagetes L.)

Abstract This study was conducted to investigate the effect of various horticultural substrates (compost, peat-coconut, peat TS1, flower soil, lowmoor peat) and a foliar spray of chlormequat (at a concentration of 1380 mg dm-3) on the growth and flowering of the marigold cultivars belonging to two species: Tagetes erecta - ʻMarvel Mixtureʼ and ʻTaishan Orangeʼ, and Tagetes patula - ʻDurango Redʼ and ʻBonanza Flameʼ. The obtained results show that the plants grown in peat TS1 and peat-coconut were taller, had longer internodes and leaves, and thicker stems than the plants grown in the other substrates. Chlormequat significantly reduced the height of ʻMarvel Mixtureʼ (in peat TS1), ʻTaishan Orangeʼ (in lowmoor peat) and ‘Bonanza Flameʼ (in peat-coconut). The use of chlormequat also accelerated the development of flower heads in ʻTaishan Orangeʼ (in lowmoor peat).