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Relationships among soil resource acquisition mechanisms and components of shoot tissue production were studied in the late-seral, grazing tolerant and competitive Stipa clarazii Ball and in the earlier-seral, less grazing tolerant and competitive S. tenuis Phil and S. ambigua Speg. History of grazing and/or fire determines abundance of these C3 perennial tussock grasses in temperate, semiarid rangelands of Argentina. We hypothesized lower values for root length density (RLD) and percentage vesicular-arbuscular mycorrhizal (%VAM) colonization on defoliated than on undefoliated plants, and also greater values for RLD and %VAM colonization on defoliated and undefoliated plants of S. clarazii than on those of the other two species, because of its greater competitive ability and defoliation tolerance. Field study was conducted within a 2-year exclosure to domestic herbivory. One group of plants was defoliated once to 5cm stubble height in early spring, while another group was defoliated twice, in early and mid-spring. A third group remained undefoliated (control). Measurements were conducted 6-10 days after each defoliation, and at the end of the growing season. RLD and %VAM colonization were similar on defoliated plants and on undefoliated controls in all three species. Greater regrowth production in S. clarazii was not associated with higher RLD and %VAM colonization in the more competitive species. The positive relationship between RLD and either dry weight production or tissue N and P concentration in these species suggests that their root activity must be maintained after defoliation to rapidly reestablish a photosynthetic canopy and keep resource supply at equilibrium. All perennial grasses showed consistently high %VAM colonization, suggesting they may function as obligate mycotrophs. The negative correlation between %VAM colonization and RLD or soil available P for S. clarazii could represent a mechanism to avoid shifts from mutualism to parasitism in the plant-mycorrhizae relationship. Se estudiaron las relaciones entre los mecanismos de adquisición de recursos del suelo y los componentes de producción de tejido foliar en la especie de etapas serales tardías, tolerante al pastoreo y competitiva Stipa clarazii Ball y en las especies de etapas serales más tempranas, menos tolerantes al pastoreo y competitivas S. tenuis Phil. y S. ambigua Speg. La historia de pastoreo y/o fuego determina la abundancia de estas gramíneas perennes cespitosas C3 en los pastizales templados semiáridos de Argentina. La hipótesis de trabajo fue que las plantas defoliadas tendrían menor densidad de longitud de raíces (DLR) y porcentaje de colonización por micorrizas vesiculares-arbusculares (%MAV) que aquellas no defoliadas, y también que las plantas defoliadas y no defoliadas de S. clarazii tendrían mayores valores de DLR y %MAV que aquellas de las otras especies, por su mayor capacidad competitiva y tolerancia a la defoliación. Se condujo un estudio bajo condiciones de campo en un área excluída al pastoreo por herbívoros domésticos durante 2 años. Un grupo de plantas fue defoliado una vez a 5cm del suelo a principios de primavera, mientras que otro grupo fue defoliado dos veces, a principios y mediados de primavera. Un tercer grupo permaneció no defoliado. Las mediciones se condujeron 6-10 días después de cada defoliación, y al final de la estación de crecimiento. DLR y %MAV fueron similares en plantas defoliadas y no defoliadas en las tres especies. La mayor producción de rebrote en S. clarazii no estuvo asociado con mayores DLR y %MAV en la especie más competitiva. La relación positiva entre DLR y producción de peso seco, o la concentración de N y P en el tejido en estas especies, sugiere que su actividad radical debe mantenerse tras la defoliación para reestablecer una superficie fotosintética y mantener la distribución de recursos en equilibrio. Todas las especies mostraron valores consistentemente altos de % MAV, sugeriendo que pueden tener una asociación mutualística obligada con las micorrizas. La correlación negativa entre %MAV y DLR o P disponible del suelo para S. clarazii podría representar un mecanismo para evitar cambios de asociación mutualística a parasítica en la relación planta-micorriza. Estudaram-se as relações entre os mecanismos de aquisição de recursos do solo e os componentes de produção de tecido foliar na espécie de etapas serais tardias, tolerante ao pastoreio e competitiva Stipa clarazii Ball e nas espécies de etapas serais mais prematuras, menos tolerantes ao pastoreio e competitivas S. tenuis Phil. e S. ambigua Speg. A história de pastoreio e/ou fogo determina a abundância destas gramíneas perenes cespitosas C3 nos pastizais temperados semi-áridos da Argentina. A hipótese de trabalho foi de que as plantas desfolhadas teriam menor densidade de longitude de raízes (DLR) e porcentagem de colonização por micorrizas vesiculares-arbusculares (%MAV) que aquelas não desfolhadas, e também que as plantas desfolhadas e não desfolhadas de S. clarazii teríam maiores valores de DLR y %MAV que aquelas das outras espécies, por sua maior capacidade competitiva e tolerância à desfolhação. Se conduziu um estudo sob condições de campo em uma área excluída ao pastoreio por herbívoros domésticos durante 2 anos. Um grupo de plantas foi desfolhado uma vez a 5 cm do solo no início da primavera, enquanto que outro grupo foi desfolhado duas vezes, no início e na metade da primavera. Um terceiro grupo permaneceu não desfolhado. As medições se conduziram 6-10 dias depois de cada desfolhação, e no final da estação de crescimento. DLR y %MAV foram similares em plantas desfolhadas e não desfolhadas nas três espécies. A maior produção de rebrote em S. clarazii não esteve associado com maiores DLR y %MAV na espécie mais competitiva. A relação positiva entre DLR e produção de peso seco, ou a concentração de N e P no tecido nestas espécies, sugere que sua atividade radical deve se manter após a desfolhação para restabelecer uma superficie fotossintética e manter a distribuição de recursos em equilíbrio. Todas as espécies mostraram valores consistentemente altos de % MAV, sugerindo que podem ter uma associação mutualística obrigada com as micorrizas. A correlação negativa entre %MAV e DLR ou P disponível do solo para S. clarazii poderia representar um mecanismo para evitar mudanças de associação mutualística a parasítica na relação planta-micorriza.

Semillas extraídas de frutos maduros de semeruco (Malpighia emarginata DC), provenientes del huerto de frutales del Posgrado de Horticultura de la Universidad Centroccidental Lisandro Alvarado (10º 01’ N), estado Lara, Venezuela, fueron seleccionadas y sembradas en una mezcla de arena y suelo con el objeto de describir el crecimiento y desarrollo del vástago y del sistema radicular de la plántula, desde la germinación hasta la caída de los cotiledones. Las evaluaciones morfológicas y de crecimiento fueron realizadas a lo largo de 13 muestreos sucesivos a partir de la germinación. Los resultados mostraron que a partir de la erección del hipocótilo, los cotiledones se tornaron verdes y comenzó el desarrollo de la plántula. La formación del vástago quedó establecida al completarse nueve eventos morfológicos cronológicamente progresivos, mientras que al sistema radicular se le identificaron seis estados de desarrollo, sincronizados con el vástago. Al finalizar el estado de plántula, 35 días en promedio luego de la germinación, la misma logró formar tres pares de hojas verdaderas completamente desarrolladas y dispuestas de manera decusada. La raíz principal alcanzó una longitud promedio de 300 mm, con ramificaciones apicales y basales de hasta tercer orden. Las plántulas mostraron inicialmente un desarrollo morfológico rápido y bien sincronizado entre sí, pero a partir de la aparición del primer par de hojas, la intensidad del crecimiento y desarrollo mostró apreciables diferencias entre plántulas atribuible a las variaciones genéticas propias de las semillas provenientes de reproducción sexual. Extracted seeds from mature fruits of acerola (Malpighia emarginata DC) from the orchard of fruit-bearing of the experimental field of the Horticulture Graduate School of the Universidad Centroccidental Lisandro Alvarado (10º 01’ N), Lara State, Venezuela, were selected and sowed in a mixture of sand soil to describe the growth and development of the seedling, from germination to the fall of cotyledons. The morphological evaluations were carried out through 13 successive samplings starting from germination. The results showed that the cotyledons achieve a green color after the hypocotyl upright. The aerial part of the seedling went through nine morphological events chronologically progressive, while the radical system showed only six events. These developmental events occurred synchronistically in the seedling as a whole. After 35 days from germination, the young acerola plant had attained three pairs of true leaves disposed in decussated arrangement. During this period, the main root reached 300 mm length and showed basal and apical ramifications up to the third order. The acerola seedling showed a fast and well synchronized morphological development at the outset but, after the first pair of leaves was formed, the growth and development showed appreciable differences among seedlings as a probable result of the genetic variations of seeds coming from sexual multiplication

Four treatments of experimental humic products and two control plots were observed to determine treatment effects on the shoot and root growth of creeping bentgrass. Data was collected in the rate of germination and the establishment rate of the seed as well as the rate of the shoot and root growth of already established creeping bentgrass. All of the humate treatments showed significant improvement to the root system growth in a high sand media. Little differences were seen between treatments and the differences observed showed no correlation to each other. The strongest treatment effects were seen in the 100% sand medium over the 80:20 plots. Luscar, Ltd.

This study evaluates the performance of a corn gluten meal when applied to Kentucky bluegrass, fine fescue, creeping bentgrass, and perennial ryegrass. Data was collected on the rate of germination, total root and shoot growth of seedlings, as well as the survival rate of the untreated control. The results of the study concluded that there was a reduction in shoot dry matter accumulation and germination in all the grass species treated with 200g m-2 corn meal gluten treatment. Effects were found to be strongest when applied the same day the grasses were seeded. Further investigation must be done to determine the safety intervals for seeding of the turfgrass following the corn meal gluten application. Pickseed

The genetic diversity of plants has traditionally been employed to improve crop plants to suit human needs, and in the future feed the increasing population and protect crops from environmental stresses and climate change. Genome-wide sequencing is a reality and can be used to make association to crop traits to be utilized by high-throughput marker based selection methods. This study describes a strategy of using next generation sequencing (NGS) data from the rice genome to make comparisons to the high-quality reference genome, identify functional polymorphisms within genes that might result in function changes and be used to study correlations to traits and employed in genetic mapping. We analyzed the NGS data of Oryza sativa ssp indica cv. G4 covering 241 Mb with ∼20X coverage and compared to the reference genome of Oryza sativa ssp. japonica to describe the genome-wide distribution of gene-based single nucleotide polymorphisms (SNPs). The analysis shows that the 63% covered genome consists of 1.6 million SNPs with 6.9 SNPs/Kb, and including 80,146 insertions and 92,655 deletions (INDELs) genome-wide. There are a total of 1,139,801 intergenic SNPs, 295,136 SNPs in intronic/non-coding regions, 195,098 in coding regions, 23,242 SNPs at the five-prime (5′) UTR regions and 22,686 SNPs at the three-prime (3′) UTR region. SNP variation was found in 40,761 gene loci, which include 75,262 synonymous and 119,836 non-synonymous changes, and functional reading frame changes through 3,886 inducing STOP-codon (isSNP) and 729 preventing STOP-codon (psSNP) variation. There are quickly evolving 194 high SNP hotspot genes (>100 SNPs/gene), and 1,513 out of 2,458 transcription factors displaying 2,294 non-synonymous SNPs that can be a major source of phenotypic diversity within the species. All data is searchable at https://plantstress-pereira.uark.edu/oryza2. We envision that this strategy will be useful for the identification of genes for crop traits and molecular breeding of rice cultivars.

Improved drought tolerance is always a highly desired trait for agricultural plants. Significantly increased drought tolerance in Arabidopsis thaliana (Columbia-0) has been achieved in our work through the suppression of ESKMO1 (ESK1) gene expression with small-interfering RNA (siRNA) and overexpression of CBF genes with constitutive gene expression. ESK1 has been identified as a gene linked to normal development of the plant vascular system, which is assumed directly related to plant drought response. By using siRNA that specifically targets ESK1, the gene expression has been reduced and drought tolerance of the plant has been enhanced dramatically in the work. However, the plant response to external abscisic acid application has not been changed. ICE1, CBF1, and CBF3 are genes involved in a well-characterized plant stress response pathway, overexpression of them in the plant has demonstrated capable to increase drought tolerance. By overexpression of these genes combining together with suppression of ESK1 gene, the significant increase of plant drought tolerance has been achieved in comparison to single gene manipulation, although the effect is not in an additive way. Accompanying the increase of drought tolerance via suppression of ESK1 gene expression, the negative effect has been observed in seeds yield of transgenic plants in normal watering conditions comparing with wide type plant.

Background: Strigolactones are a new class of plant hormones that play a key role in regulating shoot branching. Studies of branching mutants in Arabidopsis, pea, rice and petunia have identified several key genes involved in strigolactone biosynthesis or signaling pathway. In the model plant Arabidopsis, MORE AXILLARY GROWTH1 (MAX1), MAX2, MAX3 and MAX4 are four founding members of strigolactone pathway genes. However, little is known about the strigolactone pathway genes in the woody perennial plants. Methodology/Principal Finding: Here we report the identification of MAX homologues in the woody model plant Populus trichocarpa. We identified the sequence homologues for each MAX protein in P. trichocarpa. Gene expression analysis revealed that Populus MAX paralogous genes are differentially expressed across various tissues and organs. Furthermore, we showed that Populus MAX genes could complement or partially complement the shoot branching phenotypes of the corresponding Arabidopsis max mutants. Conclusion/Significance: This study provides genetic evidence that strigolactone pathway genes are likely conserved in the woody perennial plants and lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants.

Interaction between the rootstock and scion varieties (clones) was examined. Berlandieri x Riparia T. K. 5BB, Berlandieri x Riparia T.5C being the most widely used varieties in Hungary, Fercal, Ruggeri 140 being recently used on special soil conditions ; Georgikon 28 a new established variety and Berlandieri x Riparia T. 8B GK 10 clone were the rootstocks used. The V. vinifera L. varieties were a clone of Italian Riesling and two new hybrids from the same cross population f ( Noble Italian Riesling X Ezerjó) X ( Noble Italian Riesling X Pinot Gris ) }. This study presents the results how the growth habit depends on different scion/stock combinations in the first three years. Shoot growth characters were observed during the initial years after plantation in the vineyard until we got the first yields. Our results did not agree with those of Pospisilova (1977) that the anticipated vigour of shoot growth will appear later in the vineyard only. However we agree with Zimmerman (1970), who showed that the differences are caused by the rootstocks in the growth habit of vines during the first two years already. The differences in shoot elongation decreased similarly to the rootstocks in the first year of fruit production. It shows us that the intense root development caused vigorous shoot growth, which we think to be a rootstock effect. When the vegetative and generative development are balanced already, the effect of scions in shoot elongation became stronger than the effect of rootstock. We also found great differences in the maturation of wood each year from planting of the vineyard to the year of fruit production. During the first years the differences of cane maturation were greater according to the scion varieties, the means were significantly different. In the first ripening year the differences dwindled or increased due to the rootstocks. This means that the effect of the rootstock on cane maturation became stronger in the first year of fruit production.

Grapevine roots can be exposed to a range of temperatures at any particular moment because the root system can explore large volumes of soil over great depths and distances. A split-pot experiment was designed to assess how vegetative and reproductive development respond to partial and whole root-zone warming following winter dormancy. Simultaneous cooling and warming of parts of the root system slowed shoot elongation, leaf expansion and berry development compared to plants with a fully warmed root-zone, but not to the same extent as those with a fully cooled root-zone., Heterogeneity in root-zone temperature both vertically and horizontally may contribute to the uneven vegetative and reproductive growth often observed across vineyards. An experiment was designed to assess whether the warmed half of a grapevine root zone could compensate for the cooled half in terms of vegetative growth and reproductive development. We divided the root system of potted Shiraz grapevines bilaterally and applied either a cool or a warm treatment to each half from budburst to fruit set. Shoot growth and inflorescence development were monitored over the season. Simultaneous cooling and warming of parts of the root system decreased shoot elongation, leaf emergence and leaf expansion below that of plants with a fully warmed root zone, but not to the same extent as those with a fully cooled root zone. Inflorescence rachis length, flower number and berry number after fertilization were smaller only in those vines exposed to fully cooled root zones. After terminating the treatments, berry enlargement and the onset of veraison were slowed in those vines that had been exposed to complete or partial root-zone cooling. Grapevines exposed to partial root-zone cooling were thus delayed in vegetative and reproductive development, but the inhibition was greater in those plants whose entire root system had been cooled.

Phosphite's capacity to offset phosphorus deficiency was studied on tomato plants through four trials. Different application methods of phosphite (foliar or root) were studied in a nutrient film technique (NFT) disposal, providing optimum conditions for changes to feeding (starvation or nourishment). The ecophysiological approach aimed to characterise the growth and development of plants by the production of dry matter and the formation of the leaf surface, according to environmental conditions during the exponential phase. The results obtained on leaf symptoms and aerial growth emphasize that phosphite is unable to replace phosphate as a phosphorus nutrient, when applied either as a foliar spray or by incorporation in the nutrient solution. What is more, its use on phosphorus deficient plants negatively affects root growth, which is detrimental in case of mineral deficiency. However phosphite does not affect aerial and root growth when plants are normally fed with phosphate.

Under completely controlled conditions fruit set and the effective pollination periods (EPP) of apple cultivar ‘Golden Delicious’ and pear cultivar ‘Doyenne du Comice’ were evaluated as affected by autumn temperature (9°C and 24°C, apple; or 10°C, 14°C, 17°C and 22°C, pear) in combination with two spring temperatures (13°C and 19°C, apple; or 13°C and 17°C, pear). In apple the low-temperature period started just after the end of bloom, in pear the two temperature treatments were already applied in February when the trees were still in rest. In apple and pear there was no effect of the autumn temperature on fruit set. In apple, although bloom temperature was the same, the EPP was extended when the temperature was lowered just after bloom, resulting in a better fruit set in that treatment. There was no severe fruit drop (‘June drop’) between 3 and 6 weeks after full bloom in apple. In pear, fruit set was clearly lower at 17° than at 13°C; the length of the EPP was 4–6 days at 13°C against 2–4 days at 17°C. A marked fruit drop occurred between 3 and 6 weeks after bloom in pear. The data are discussed in terms of a differential effect of temperature on ovule longevity and rate of pollen tube growth.

The effect of assimilate supply on axillary bud development and subsequent shoot growth was investigated in roses. Differences in assimilate supply were imposed by differential defoliation. Fresh and dry mass of axillary buds increased with increased assimilate supply. The growth potential of buds was studied either by pruning the parent shoot above the bud, by grafting the bud or by culturing the bud in vitro. Time until bud break was not clearly affected by assimilate supply during bud development, Increase in assimilate supply slightly increased the number of leaves and leaf primordia in the bud; the number of leaves preceding the flower on the shoot grown from the axillary bud substantially increased. No difference was found in the number of leaves preceding the flower on shoots grown from buds attached to the parent shoot and those from buds grafted on a cutting, indicating that at the moment of release from inhibition the bud meristem became determined to produce a specific number of leaves and to develop into a flower. Assimilate supply during axillary bud development increased the number of pith cells, but the final size of the pith in the subsequent shoot was largely determined by cell enlargement, which was dependent on assimilate supply during shoot growth. Shoot growth after release from inhibition was affected by assimilate supply during axillary bud development only when buds sprouted attached to the parent shoot, indicating that shoot growth is, to a major extent, dependent on the assimilate supply available while growth is taking place.

The effect of axillary bud age on the development and potential for growth of the bud into a shoot was studied in roses. Age of the buds occupying a similar position on the plant varied from 'subtending leaf just unfolded' up to 1 year later. With increasing age of the axillary bud its dry mass, dry-matter percentage and number of leaves, including leaf primordia, increased. The apical meristem of the axillary bud remained vegetative as long as subjected to apical dominance, even for 1 year. The potential for growth of buds was studied either by pruning the parent shoot above the bud, by grafting the bud or by culturing the bud in vitro. When the correlative inhibition (i.e. domination of the apical region over the axillary buds) was released, additional leaves and eventually a flower formed. The number of additional leaves decreased with increasing bud age and became more or less constant for axillary buds of shoots beyond the harvestable stage, while the total number of leaves preceding the flower increased. An increase in bud age was reflected in a greater number of scales, including transitional leaves, and in a greater number of non-elongated internodes of the subsequent shoot. Time until bud break slightly decreased with increasing bud age; it was long, relatively, for 1 year old buds, when they sprouted attached to the parent shoot. Shoot length, mass and leaf area were not clearly affected by the age of the bud that developed into the shoot. With increasing bud age the number of pith cells in the subsequent shoot increased, indicating a greater potential diameter of the shoot. However, final diameter was dependent on the assimilate supply after bud break. Axillary buds obviously need a certain developmental stage to be able to break. When released from correlative inhibition at an earlier stage, increased leaf initiation occurs before bud break.

Nous avons étudié pendant 3 ans, en serre et en plein champ, l'effet sur la vigne (cépage Merlot) d'applications foliaires de 9 produits commerciaux associant à une fraction minérale divers constituants organiques, et conseillés pour stimuler la végétation et améliorer la récolte. Nous nous sommes intéressés à la croissance des rameaux et à la production (coulure, rendement, teneur en sucre des moûts).Dans nos conditions expérimentales, ces produits ont peu modifié, et de façon aléatoire, les paramètres mesurés. L'intérêt de l'utilisation de telles substances dans la pratique viticole reste donc à démontrer.