Stem Nodes Research Articles

Effects of node restriction on cadmium accumulation in eight Chinese wheat (Triticum turgidum) cultivars

Minimization of cadmium (Cd) accumulation in wheat is an effective method to prevent Cd-related health risks to humans. To understand the underlying mechanisms of restricting Cd transport, the role of nodes in Cd restriction was studied in eight Chinese wheat cultivars. The Cd accumulation differed significantly among the cultivars. The grain Cd concentrations were mainly dependent on the Cd concentrations in the roots and shoots. The Cd transport in the shoots controlled the wheat grain Cd accumulations. Nodes in the wheat stem have distinct functions in the transfer, distribution, and restriction of Cd. The node connected to the panicle showed the lowest translocation factors. The area of the vascular bundles, especially the diffuse vascular bundles, in the junctional node with the flag leaf was the key factor in restricting Cd transfer to the wheat grain. There was a significant relation between these areas and the grain Cd concentrations. The conclusion of this study is that screening or breeding cultivars with low Cd concentrations in the roots or with smaller areas of diffuse vascular bundles in the junctional nodes with the flag leaf is an effective strategy to decrease Cd concentration in wheat grains.

Emetine and cephaeline production and regulation by in vitro propagation of Psychotria ipecacuanha (Brot.) Stokes in semi-solid media and temporary immersion bioreactor

Psychotria ipecacuanha, is a plant species with known medicinal properties that is critically endangered due to overexploitation of natural populations. Although the difficulties in conventional propagation by seed and by vegetative propagation are generally understood, the present study enhances our knowledge by describing efficient plant regeneration and root induction protocols for P. ipecacuanha while comparing alkaloid content (emetine and cephaeline) in in vitro-derived tissues. Stem node explants were cultured on MS medium MS supplemented with indolbutiric acid (IBA) in semi-solid media and the RITA® temporary immersion bioreactor. The highest root formation (81%) was in MS + 1.5 mg L−1 IBA in the bioreactor. After 24 months of acclimatization, the plants cultivated in MS + 0.50 and 1.0 mg L-1 of IBA had the highest number of roots (3), with mean values of 10.47 and 9.40 cm, respectively. The cultures coming from 1.0 mg L−1 and 0.5 mg L−1 IBA in the bioreactor contained higher cephaeline content, with a relative area of 14.2 and 14.9%, respectively. For emetine, the 1.0 mg L−1 IBA cultures in the bioreactor, 0.5 mg L−1 IBA and MS0 cultures contained higher content than the other treatments, with a relative area of 10.2, 10.2 and 10.1%, respectively.

Exploring the QTL–allele constitution of main stem node number and its differentiation among maturity groups in a Northeast China soybean population

AbstractNortheast China (NEC) is a major soybean [Glycine max (L.) Merr.] production region in China, where the germplasm of American soybeans are mainly from. The main stem node number (MSN) is a trait related to plant type and yield potential. With the soybeans expanded to higher latitudes in NEC, earlier maturity groups (MG 0, MG 00, and MG 000) formed based on MG I + MG II (MG I+II), and correspondingly the MSN decreased. To explore the MSN quantitative trait locus (QTL)–allele constitution, 306 accessions from NEC were studied using the restricted two‐stage multilocus genome‐wide association study (RTM‐GWAS) procedure. In total, 76 MSN QTLs and 183 alleles were identified, with their genetic contribution about 0.04–9.83% per locus for a total of 65.63% for all loci. With the MSN reduction from MG I+II to MG 0, MG 00, and MG 000 (17.89 to 13.11), the changed alleles accounted for 28.42% of all alleles (6.56% for new allele emergence plus 21.86% for old allele exclusion), whereas the major part of the alleles were those inherited from MG I+II (71.58%). Thus in the evolution of MSN in the NEC soybean population, inheritance is the first genetic motivation, exclusion and selection (positive allele exclusion, 65.00%) is the second, emergence and mutation (negative allele emergence, 95.67%) is the third, and recombination among retained alleles is the fourth. A potential of 2–5 MSN improvement keeping the MG earliness was predicted, and 49 candidate genes were identified.

Relative contribution of expected sum of squares values for soybean genotypes × growing environments interaction

The objective of this work was to assess the effects and tendencies weighted by genotypes x environments interaction for soybean, as well as to employ a biometric approach through the relative contribution of the sum of squares expected values (RCSS) and to define which levels of the variation sources determine the differential effects of the interaction. The experimental design was randomized blocks arranged in a factorial scheme (four growing environments x 20 soybean genotypes). The relative contribution of expected sums of squares values to soybean genotypes x growing environments interaction defined that the environment Tenente Portela - RS significantly influence plant height, number of pods per plant, number of reproductive nodes in the main stem, number of reproductive nodes in the ramifications, number of grains per plant and grain yield. The variation factor soybean genotypes define that number of pods per plant, number of reproductive nodes in the ramifications, number of grains per plant and grain yield are potentiated by genotype TMG 7161 RR. The biometric approach is efficient to understand the treatment levels and the slicing of simple effects of a factorial experiment, being possible to apply this methodology extensively in soybean.

Selection of Urban Shade Tolerant Ground Cover Plant Through Photochemical Assessment

In this study, we performed to selection of urban shade tolerant ground cover plant through growth and photochemical reaction analysis. Plants that are not properly planted according to their biological requirements under different growth conditions cause several problems such as poor growth and withering, which wastes an enormous amount of time and budget for maintenance. Multi-layer planting is designed to ensure vegetation resources that lack mobility have their native ecological characteristics, respond to different living environments and show different growth patterns as they are affected by factors such as sunlight on the ground and underground moisture. Against this backdrop, this study aimed to provide base information for planting designs through the evaluation of the growth and photochemical reaction of plants under different partial shading conditions. The results of this study are expected to be utilized in planning and designing planting to reduce factors that may cause flaws in landscape planting and minimize the burden of maintenance. Under different shading conditions (0%, 50% and 80% shading), distinct changes in the growth of plants were observed. Pachysandra terminalis ‘Variegata’, Physostegia virginiana, Carex maculata, Veronica linariifolium are recommended to be planted in 50% - 80%-shading spaces. We performed to evaluate and analyze the growth and light utilization efficiency of garden plants in the shade area through chlorophyll fluorescence reaction analysis. Under shading, the fluorescence parameter related with electron-transport in photosystem II, ET2O/RC was effectively enhanced whereas the electron transport flux until PSI acceptors per reaction center (RE1o/RC) reduced. In addition, some photochemical parameters such as RC/ABS, RE1O/RC, DIo/RC, DFTOTAL ABS were important for the determination of shade tolerance. On the basis of these results, the shade tolerant index deduced from growth and photochemical parameters were useful for an evaluation of shading stress in urban ground cover plants. Changes of plant height and length of stem node every two weeks of Pachysandra terminalis ‘Variegata’ by non shading (top left), 50% shading (top right), and 80% shading (bottom left) treatment relatively. Different letters in one measurement indicate statistically significant difference at p ≤ 0.05 by Duncan multiple range test.

Transcriptome analysis reveals the roles of stem nodes in cadmium transport to rice grain

BackgroundNode is the central organ of transferring nutrients and ions in plants. Cadmium (Cd) induced crop pollution threatens the food safety. Breeding of low Cd accumulation cultivar is a chance to resolve this universal problem. This study was performed to identify tissue specific genes involved in Cd accumulation in different rice stem nodes. Panicle node and the first node under panicle (node I) were sampled in two rice cultivars: Xiangwanxian No. 12 (low Cd accumulation cultivar) and Yuzhenxiang (high Cd accumulation cultivar). RNA-seq analysis was performed to identify differentially expressed genes (DEGs) and microRNAs.ResultsXiangwanxian No. 12 had lower Cd concentration in panicle node, node I and grain compared with Yuzhenxiang, and node I had the highest Cd concentration in the two cultivars. RNA seq analysis identified 4535 DEGs and 70 miRNAs between the two cultivars. Most genesrelated to the “transporter activity”, such as OsIRT1, OsNramp5, OsVIT2, OsNRT1.5A, and OsABCC1, play roles in blocking the upward transport of Cd. Among the genes related to “response to stimulus”, we identified OsHSP70 and OsHSFA2d/B2c in Xiangwanxian No. 12, but not in Yuzhenxiang, were all down-regulated by Cd stimulus. The up-regulation of miRNAs (osa-miR528 and osa-miR408) in Xiangwanxian No. 12 played a potent role in lowering Cd accumulation via down regulating the expression of candidate genes, such as bZIP, ERF, MYB, SnRK1 and HSPs.ConclusionsBoth panicle node and node I of Xiangwanxian No. 12 played a key role in blocking the upward transportation of Cd, while node I played a critical role in Yuzhenxiang. Distinct expression patterns of various transporter genes such as OsNRT1.5A, OsNramp5, OsIRT1, OsVIT2 and OsABCC1 resulted in differential Cd accumulation in different nodes. Likewise, distinct expression patterns of these transporter genes are likely responsible for the low Cd accumulation in Xiangwanxian No. 12 cultivar. MiRNAs drove multiple transcription factors, such as OsbZIPs, OsERFs, OsMYBs, to play a role in Cd stress response.

A Domestication-Associated Gene GmPRR3b Regulates the Circadian Clock and Flowering Time in Soybean

Improved soybean cultivars have been adapted to grow at a wide range of latitudes, enabling expansion of cultivation worldwide. However, the genetic basis of this broad adaptation is still not clear. Here, we report the identification of GmPRR3b as a major flowering time regulatory gene that has been selected during domestication and genetic improvement for geographic expansion. Through a genome-wide association study of a diverse soybean landrace panel consisting of 279 accessions, we identified 16 candidate quantitative loci associated with flowering time and maturity time. The strongest signal resides in the known flowering gene E2, verifying the effectiveness of our approach. We detected strong signals associated with both flowering and maturity time in a genomic region containing GmPRR3b. Haplotype analysis revealed that GmPRR3bH6 is the major form of GmPRR3b that has been utilized during recent breeding of modern cultivars. mRNA profiling analysis showed that GmPRR3bH6 displays rhythmic and photoperiod-dependent expression and is preferentially induced under long-day conditions. Overexpression of GmPRR3bH6 increased main stem node number and yield, while knockout of GmPRR3bH6 using CRISPR/Cas9 technology delayed growth and the floral transition. GmPRR3bH6 appears to act as a transcriptional repressor of multiple predicted circadian clock genes, including GmCCA1a, which directly upregulates J/GmELF3a to modulate flowering time. The causal SNP (Chr12:5520945) likely endows GmPRR3bH6 a moderate but appropriate level of activity, leading to early flowering and vigorous growth traits preferentially selected during broad adaptation of landraces and improvement of cultivars.

Pengaturan Arsitektur Tanaman untuk Menyeimbangkan Sink dan Source serta Meningkatkan Pertumbuhan dan Hasil Kacang Koro Pedang

The research to improve the growth, production, and seed quality of Jack Bean (Canavalia ensiformis L.) through pruning, which was carried out from May to October 2016 in Purwasari Village, Dramaga, Bogor Regency and continued by seed testing at the Seed Testing Laboratory, Bogor Agricultural University in December 2016. The research was designed in a randomized block design (RBD) with eight treatment of stem and branch pruning and one treatment without pruning as a control, i.e. without pruning of branches and stems (P1), pruning on the 10th stem nodes (P2 ), pruning on the 11th stem nodes (P3), pruning on the 5th branch nodes (P4), pruning on the five branch nodes and the 10th stem nodes (P5), pruning on the 5th branch nodes and stem nodes to -11 (P6), pruning on the 6th branch nodes (P7), pruning on the 6th branch nodes and 10th stem nodes (P8), and pruning on the 6th branch nodes and 11th stem nodes (P9). The results showed that pruning affected some of the results of the study, but was not able to increase the production of Jack Bean. Pruning treatment on the 5th branch nodes and 10th stem nodes (P5) produced the highest seed production (3.4 tons ha-1), the physical quality of the seeds produced was classified as moderate with a weight of 1000 seeds between 1273.3-1291.7 g. The physiological quality of the seed is moderate with maximum growth potential 84.0-90.7%, germination percentage 73.3-82.7%, germination speed 9.1-116.1% / etmal, germination uniformity 40.0-49 , 3% and vigor index of 14.0-20.0%. Keywords: germination rate, inflorescence, oas bakol, pod

Identification of Traits Contributing to High and Stable Yields in Different Soybean Varieties Across Three Chinese Latitudes.

Soybean yield is a complex quantitative trait, which is greatly affected by environmental conditions. The main objective of this study is not only to identify specific traits contributing to yield in different latitudes, which can be further used in breeding, but also to identify the outperforming varieties, as this can help to select new lines with these traits. One hundred and seventy-three soybean genotypes were tested in three different ecological environments, including Harbin, Changchun, and Shenyang in China during 2015–2016 cropping seasons. The evaluation on the different agronomic and physiological traits indicated that the soybean varieties with higher plant height, more nodes of main stem, branches, pods, grains, and 100-grain weight, or longer growth periods may have higher yield. Pods, grains and 100-grain weight can be used as direct selection criteria for yield increase, and likewise the other traits such as plant height, nodes of main stem, branches, growth periods indirectly affected yield by affecting the three traits above. The effect of genotype × environment (G × E) interaction on different agronomic traits was significant. The representativeness and discriminability for grains yield per plant was the most significant in Harbin, which could be used to screen varieties with high yield and wider adaptability. Genotype “Suinong 1” was considered stable with higher value of grain yield per plant than other genotypes used in this study. As the yield of certain soybean cultivars may be significantly reduced if they are grown in a region as little as 2°N beyond its normal cultivation latitudes, therefore, the identification and analysis on the stable and widely adaptive soybean genotypes would be very important, and it would provide the significant reference accordance of soybean variety selection for the soybean breeders.

Sugarcane stem nodes based on the maximum value points of the vertical projection function

ABSTRACT: In order to solve the problem that the stem nodes are difficult to identify in the process of sugarcane seed automatic cutting, a method of identifying the stem nodes of sugarcane based on the extreme points of vertical projection function is proposed in this paper. Firstly, in order to reduce the influence of light on image processing, the RGB color image is converted to HSI color image, and the S component image of the HSI color space is extracted as a research object. Then, the S component image is binarized by the Otsu method, the hole of the binary image is filled by morphology closing algorithm, and the sugarcane and the background are initially separated by the horizontal projection map of the binary image. Finally, the position of sugarcane stem is preliminarily determined by continuously taking the derivative of the vertical projection function of the binary image, and the sum of the local pixel value of the suspicious pixel column is compared to further determine the sugarcane stem node. The experimental results showed that the recognition rate of single stem node is 100%, and the standard deviation is less than 1.1 mm. The accuracy of simultaneous identification of double stem nodes is 98%, and the standard deviation is less than 1.7 mm. The accuracy of simultaneous identification of the three stem nodes is 95%, and the standard deviation is less than 2.2 mm. Compared with the other methods introduced in this paper, the proposed method has higher recognition and accuracy.

The productivity and sucrose content on dry land sugarcane influenced by inter-row spacing and transplanting seedlings

Planting sugarcane on dry land is susceptible to drought stress during the vegetative phase thereby reducing productivity. The objectives of this study were to examine the growth and yield of sugarcane transplanting seedling and ascertain their physiological-growth-traits to determine the productivity and sucrose content. The experiment design was a completely randomized block design with four replicates. The treatments were: five varieties and four inter-row spacing of single bud chips seedlings. The study was conducted in Gunung Kidul, Yogyakarta. The parameters were evaluated using analysis of variance followed by Duncan’s multiple range test and analyzed using step-wise regression. The application of 60cm inter-row spacing increase the yield of millable cane by 101.7 tons/ha and sucrose content compared with control, respectively by 38.8%, 5.8%. The net photosynthesis (Pn) of nine months, leaf area index of four months, specific leaf weight of five months, the proline content of nine months and net assimilation rate at the age of six months determined the productivity. The physiological determinants of sugar content were Pn at the age of nine months, stem brix, even distribution of brix on the stem nodes, and level of chlorophyll.

Influence of the Interaction of the Mutant Inl Gene and the Type of Fruiting Branches ss on the Anatomical Features of the Stem in the Indeterminate and Determinant Forms of <i>G. hirsutum</i> L.

For the first time, a comparative analysis of the structure of the apical meristem and the node of the main shoot of two forms of the indeterminate kind Namangan-77 and the determinant line of Determinant-2 and Determinant-3 of G. hirsutum in the kidney ding phase was carried out. In the apical meristem of the indeterminate form Namangan-77 is characterized by the recessive homozygous state of the mutant gene (inlinl) and the dominant homozygous, heterozygous state of the fruiting branch gene S-s: inlinlSS, inlinlSs, inlinlss—more pronounced vegetative, vegetative, with this, this form is predominated by the continuation of first-order shoots and the monopodial branching type with unlimited apical growth, accompanied by a uniform elongation of the internodes. In the apical meristem, in the forms of the determinant lines, Determinant-2 and Determinant-3 are characterized by the dominant homozygous state of the mutant gene (InlInl) and the recessive homozygous state of the allelic gene (ss)—InlInlss—there is a generative collateral kidney in the axillary leaf axial sinus, which is why these forms of the vegetative apex of the shoot when they transit to the reproductive state turn into a floral apical meristem and a sympodial branching type what happens through the development of inflorescences. Obviously, this is a consequence of a change in the phytohormonal status in the apical part of the stem as a result of the interaction of the mutant gene Inl and gene S. The node of the main stem in all forms was also studied, and a three-beam-three-lacuna type of structure was revealed, which is a fairly persistent characterizing feature of large taxa and can be used in their taxonomy.

三峡库区多年高水位运行对消落带狗牙根生长恢复的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡库区多年高水位运行对消落带狗牙根生长恢复的影响 DOI: 10.5846/stxb201809061909 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（51409030）；重庆市科委自然科学基金计划项目（cstc2015jcyjA 20028）；重庆高校创新团队建设计划项目（CXTDX201601037）；重庆市技术创新与应用发展专项面上项目（csct2019jscx-msxm0578） Influence of multi-year high water level running on growth recovery of Cynodon dactylon population in water-level-fluctuating zone of the Three Gorges Reservoir Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为深入了解三峡库区多年高水位运行对消落带优势植物生长恢复的影响，分别于2008年和2017年定量调研了库区长寿段消落带狗牙根（Cynodon dactylon）种群的变化，探讨了库区高水位运行对消落带狗牙根萌发、生长和物质分配的影响。结果表明，多年的高水位运行导致不定芽形成和萌发显著被促进，形成更多的分株；高水位运行导致狗牙根分株的株高、茎宽和叶片数被显著抑制，而叶长和种群的总叶片数被显著促进，且随着消落带水位的降低叶长呈降低趋势，而叶宽和总叶片数呈增加趋势；高水位运行导致狗牙根种群匍匐茎和地下茎的茎长、茎节数和总茎长均被显著促进，且随着消落带水位降低匍匐茎茎长和茎节数呈显著的降低趋势，而地下茎茎长和茎节数呈增加趋势；高水位运行导致狗牙根地下茎储存的干质量呈增加趋势，而分株和匍匐茎的干质量呈降低趋势，而且在种群物质分配中地下茎所占的比例呈增大趋势，低水位狗牙根种群的分株和高水位种群的匍匐茎所占的比例也呈增加趋势。因此，狗牙根不仅具有很强的耐淹和生长恢复能力，也具有很强的拓殖能力，可以作为库区中低位消落带恢复和重建的主要原生物种。 Abstract:To clarify influence of multi-year high water level running on growth recovery of dominant plants in water-level-fluctuating zone of the Three Gorges Reservoir, the quantitative changes of Cynodon dactylon population in Changshou area were investigated in 2008 and 2017. We also discussed the influences of high water level on the germination, growth, and material allocation of C. dactylon. The results showed that multi-year high water level running significantly promoted the formation and germination of adventitious buds which made more ramets to be formed. Multi-year high water level running significantly restrained plant height, stem width, and leaf number of the ramets, while leaf length and total leaf number of the population were significantly promoted. Furthermore, the leaf length was decreased with water level decreasing. However, the leaf width and total leaf number showed the opposite increasing trend. Simultaneously, multi-year high water level running led to the significant promotion of stem length, stem nodes number and total stem length of stolons and rhizomes. The stem length and stem nodes number of the stolons were decreased with the water level decreasing. On the contrary, stem length and stem nodes number of the rhizomes were increased with water level decreasing. As a result of high-water-level operation for many years, dry mass of the rhizomes showed an increasing trend, while dry mass of the ramets and the stolons showed an opposite decreasing trend. In addition, the proportion of the rhizomes, ramets in low water level, and stolons in high water level also showed an increasing trend in material distribution of the population. Therefore, C. dactylon not only have strong flood resistance and growth recovery ability, but also have strong colonization ability, which can be used as one of the primary native species for vegetation recovery and reconstruction of in low or middle water-level-fluctuating zone of the Three Gorges Reservoir. 参考文献 相似文献 引证文献

Modeling leaf area development in soybean (Glycine max L.) based on the branch growth and leaf elongation

ABSTRACT Several models have been proposed to simulate the leaf area index (LAI) in soybean (Glycine max L.); however, these models do not directly account for the effect of branch growth. Because the increases in branches and branch node vary with plant density, the evaluation of branch growth is necessary for the application of the LAI model at various plant densities. In this study, we developed an LAI model for soybean, considering the branch growth and leaf elongation at each node. To simplify this model, we estimated the rate of branch and branch node increase based on the rate of main stem node increase. Branch growth was assumed to be restricted when the fraction of canopy radiation interception was increased. Moreover, we calculated the leaf area growth at each node based on leaf elongation at each leaflet. This LAI model was validated using the data of different years and plant densities for model calibration, and it estimated the LAI with a root mean square error of 0.76, which accounted for 92% of the variation in the data. Although further evaluation is needed, the LAI model proposed in this study reveals a high potential for accurate estimation of LAI at various plant densities.

Geographic differentiation and phylogeographic relationships among world soybean populations

A fast-growing protein and oil crop, soybean was domesticated in ancient China and disseminated early in Asia and afterwards to other continents, in particular the Americas in recent centuries. After adaptation, locally developed landraces and cultivars formed a diversity of geographic-populations. In an investigation of their phylogeographic features, marker-derived traits were combined with geography-related photo- and temperature-sensitive traits to study 13 geographic-populations comprising 371 accessions. Extreme differentiation among geographic-populations was observed for flowering date (33–94 days), maturity date (79–181 days), and main stem node number (6–25 nodes). Restriction-site associated DNA sequencing revealed strong genetic differentiation among these geographic-populations, including genetic richness (alleles, 35,242–44,986) and specific-present alleles (SPAs, 0–67). More SPAs (28–67) emerged in some secondary and tertiary centers than in centers of origin (8–11). Phenotypic and genotypic clustering divided 11 of the 13 geographic-populations into the same five sets of sensitivity-similar geographic-populations and grouped the populations of northeast China and northern North America rather than center-of-origin populations as secondary centers, indicating the importance of geography-related traits in determining genetic differences among geographic-populations. A model of four soybean dissemination paths is presented: from the center of origin to the north, east, and south in Asia and from northeast China to Europe and the Americas. These findings provide a detailed phylogeographic understanding of worldwide soybeans.

JAK2-mutant hematopoietic cells display metabolic alterations that can be targeted to treat myeloproliferative neoplasms

AbstractIncreased energy requirement and metabolic reprogramming are hallmarks of cancer cells. We show that metabolic alterations in hematopoietic cells are fundamental to the pathogenesis of mutant JAK2–driven myeloproliferative neoplasms (MPNs). We found that expression of mutant JAK2 augmented and subverted metabolic activity of MPN cells, resulting in systemic metabolic changes in vivo, including hypoglycemia, adipose tissue atrophy, and early mortality. Hypoglycemia in MPN mouse models correlated with hyperactive erythropoiesis and was due to a combination of elevated glycolysis and increased oxidative phosphorylation. Modulating nutrient supply through high-fat diet improved survival, whereas high-glucose diet augmented the MPN phenotype. Transcriptomic and metabolomic analyses identified numerous metabolic nodes in JAK2-mutant hematopoietic stem and progenitor cells that were altered in comparison with wild-type controls. We studied the consequences of elevated levels of Pfkfb3, a key regulatory enzyme of glycolysis, and found that pharmacological inhibition of Pfkfb3 with the small molecule 3PO reversed hypoglycemia and reduced hematopoietic manifestations of MPNs. These effects were additive with the JAK1/2 inhibitor ruxolitinib in vivo and in vitro. Inhibition of glycolysis by 3PO altered the redox homeostasis, leading to accumulation of reactive oxygen species and augmented apoptosis rate. Our findings reveal the contribution of metabolic alterations to the pathogenesis of MPNs and suggest that metabolic dependencies of mutant cells represent vulnerabilities that can be targeted for treating MPNs.

EFFECTS OF AZOLLA BIOMASS GROWTH ON FLOOD WATER TEMPERATURE AND PH, TILLERING AND YIELD OF PADDY RICE

<p><em>Azolla</em> is a floating pteridophyte, which forms an association with an endosymbiont, the nitrogen-fixing cyanobacterium <em>Anabaena azollae</em>. In Mwea Irrigation Scheme paddies, <em>Azolla</em> biomass coverage ranges from 25 to 50 % with a high biomass growth rate and this has caused a challenge in its management. Knowledge on the effect of <em>Azolla</em> biomass on rice tillering, root development and grain yield are important in order to exploit its potential benefits in Mwea Irrigation Scheme, where nearly 60 % of the total rice in Kenya is produced. The effect of <em>Azolla</em> on tillering, plant biomass, adventitious roots development, basal internode growth and yield of rice, was studied during 2015/2016 short and long rains. <em>Azolla</em> was inoculated in 30 cm x 30 cm plastic pots planted with rice variety Basmati 370. Controls where no <em>Azolla</em> was inoculated were included. Tiller number, plant height, flood water temperature and pH were determined at 21, 32, 42, 60 and 75 days after transplanting (DAT). At 120 DAT, grain yield and yield components were determined. Length of basal node and adventitious root were measured and dry biomass weights of, root and above ground biomass determined. Water temperature in <em>Azolla</em> inoculated pots were significantly lower than in controls by 0.8 °C and 1.3 °C in the second and first seasons respectively with a daily fluctuation of 2 °C. The pH of flood water in potted rice inoculated with <em>Azolla</em> was significantly lower than in control. <em>Azolla</em> inoculated potted rice had significantly higher number of tillers/m<sup>2</sup>, spikelets per panicle<sup>-1</sup>, panicle size m<sup>-2</sup>, 1000 grain weight and plant biomass than in non-inoculated controls. Adventitious roots were significantly longer and more per unit area in all treatments than in controls. The basal stem node length was significantly shorter while root biomass was less for the <em>Azolla</em> inoculated potted rice than in controls. In all treatments, <em>Azolla</em> doubled its biomass within an average of 5 days.</p><p> </p><p> </p>

Struktur Anatomi Daun Artemisia cina Berg. Ex Poljakov Hasil Kultur Jaringan

This study was conducted to investigate the anatomical structure of leaves of Artemisia cina Berg. ex Poljakov due to variances in leaf morphology during grown in vitro. Shaking of culture, position of stem nodes used as explants and concentration of BAP (Benzyl Amino Purin) added to the culture medium were the factors investigated in this study. There was variation in leaves morphology of culture, however this variation did not occur after aclimatization and plant grown in the greenhouse. BAP decreased the level of chlorophyll content of leaves. In general, anatomical characters of leaves were not influenced by shaking, nodes position of stem and level of BAP.

Sensitivity of Seeds to Chemical Mutagens, Detection of DNA Polymorphisms and Agro-Metrical Traits in M1 Generation of Coffee (Coffea arabica L.)

Coffee (Coffea Arabica L.) is threatened by biotic and abiotic stresses. Nevertheless, the breeding of Arabica coffee is restricted due to its low genetic diversity. Crop improvement via mutagenesis represents an alternative for increasing genetic variability and facilitating breeding. In this sense, coffee seeds cv. Catuai were treated for 8 h with a solution of sodium azide (NaN3) (0, 50, 75, 100, and 125 mM) and ethyl methane sulfonate (EMS) (0, 80, 160, 240, 320, and 400 mM). The genetic variability induced in coffee plants after mutagenic treatment with sodium azide was determined by RAPD and AFLP analyses. As the concentration of applied NaN3 and EMS increased, the germination, seedling height, and root length decreased. The LD50 values for NaN3 and EMS were between 50-75 mM and 160-240 mM, respectively. For the 12 RAPD primers evaluated, a total of 46 fragments were obtained of which 34 were polymorphic bands (74%). The amplification with six AFLP selective primer combinations allowed the identification of 36 polymorphisms (17.8%). The analysis revealed that both NaN3 and EMS induced variability within the DNA regions amplified with AFLP and RAPD markers. Finally, under field conditions, significant differences were noticed with respect to plant height, number of nodes in the orthotropic stem, and number of branches of the M1 mutant (NaN3-treated) plants compared to the non-mutant plants. Optimal conditions for NaN3 and EMS mutagenesis using seeds were determined and the optimized conditions have been used to generate a NaN3 mutant M1 coffee var. Catuai population.

Genome-wide identification and characterization, phylogenetic comparison and expression profiles of SPL transcription factor family in B. juncea (Cruciferae).

SQUAMOSA promoter-binding protein-like (SPL), as plant specific transcription factors, is involved in many plant growth and development processes. However, there is less systematical study for SPL transcription factor in B. juncea (Cruciferae). Here, a total of 59 SPL genes classified into eight phylogenetic groups were identified in B. juncea, highly conserved within each ortholog were also found based on gene structure, conserved motif, as well as clustering level. In addition, clustering of SPL domain showed that two zinc finger-like structures and NLS segments were identified in almost of BjuSPLs. Analyzed of putative cis-elements for BjuSPLs demonstrated that SPL transcription factors were involved in adverse environmental changes, such as light, plant stresses and phytohormones response. Expression analysis showed that differentially expressed SPL genes were identified in flower and stem development of Cruciferae; such as BjuSPL3a-B, BjuSPL2b_B and BjuSPL2c_A were significantly expressed in flower; BjuSPL 3b_B and BjuSPL10a_A were significantly expressed in stem node (VP: vegetative period). Moreover, 28 of the 59 BjuSPLs were found involved in their posttranscriptional regulation targeted by miR156. We demonstrated that miR156 negatively regulated BjuSPL10a_A and BjuSPL3b_B to act for stem development in B. juncea.