Stem Height Research Articles

Fungal Presence and Changes of Wood Structure in Bark Stripping Wounds Made by Red Deer (Cervus elaphus L.) on Stems of Fraxinus angustifolia (Vahl)

Narrow-leaved ash (Fraxinus angustifolia Vahl), a highly valued European forest tree species, has been severely affected by a large-scale decline, which is most probably driven by a complex of multiple interacting factors including fungi, which contribute to and accelerate this process. Red deer (Cervus elaphus L.) can be considered as one of the contributing factors, as they inflict damage on the stems of young trees by stripping the bark. These wounds not only represent suitable entry points for fungi which can cause tissue necroses and decomposition, they can lead to changes in the wood structure as well. The aims of this research were to analyze chosen parameters of bark stripping wounds in narrow-leaved ash stands, identify fungi present in the tissue exposed by wounding, and inspect the effect of wounding on the wood structure. Bark stripping was observed on ash trees from 2 cm up to 18 cm of DBH and between 0.1 m and 1.9 m of stem height. The most susceptible trees were those with an average DBH of 5 ± 2.5 cm. On most of the ash trees (51%), one-third to two-thirds of the circumference was damaged. In wounded tissue, 174 fungal isolates were found, most of which belonged to known endophytic fungi from the genera Trichoderma, Fusarium, and Clonostachys. It was observed that earlywood cells in the wounding zone had narrower lumens compared to ones in adjacent healthy zone with regard to different trees and stem heights.

The effect of corn (Zea mays L.) kernel extract as a natural growth regulator in pacthouli (Pogostemon cablin Benth.) subculture plantlet

Patchouli is an essential oil producing plant which has high demand in the market. The high demand for patchouli cannot be met by conventional methods so it is diverted to use the in-vitro culture method. In-vitro culture media and plant growth regulators (PGR) are the keys to the success of culture. The study was conducted using corn kernel extract as natural PGR on in-vitro culture media with the aim of observing the effect of corn kernel extract on Patchouli plant explants. This research was designed in a completely randomized design with 6 treatments and 5 replications, namely the addition of 2, 6, 12, 18, 24 mg/L extract and no extract as a control. The parameters measured in this study were stem height, number of shoots, number of leaves and number of roots. The research results showed that the addition of corn kernel extract has a significant effect on stem height and number of roots, inversely for number of shoots and number of leaves. Media sterilization is thought to damage natural PGR due to the low stability of PGR. The starch content in corn kernel extract is thought to have the potential to inhibit the growth of Aceh patchouli explants.

Design modification and selection of improved stem design of the conical stem tibial implant for TAR using FE analysis and different MCDM methods.

The conical stem tibial design of total ankle replacement (TAR) has high implant-bone micromotion. This may lead to aseptic loosening which can be avoided by improving the tibial design. The objective was to propose the best stem design parameters to reduce implant-bone micromotion along with minimizing stress shielding using an integrated Finite Element-Multi Criteria Decision Making (FE-MCDM) approach. FE models of implanted tibia bones were prepared by changing the height of the stem, the diameter of the stem, and the slant of the stem. Weighted Aggregated Sum Product Assessment (WASPAS), Technique for Order of Preference by Similarities to Ideal Solution (TOPSIS), Evaluation based on Distance from Average Solution (EDAS), and VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) MCDM techniques with equal weights for micromotion and stress shielding were considered. The micromotion and stress shielding were greater when the height of the stem was increased. Whereas, the increase in diameter and slant affected them marginally. The best-performing design was the Model with stem height 6 mm (diameter 6.4 mm and slant 4°) and after that was the Model with stem height 8 mm (diameter 6.4 mm and slant 4°), and then the Model with stem height 10 mm (diameter 6.4 mm and slant 4°). The height of the stem is the most important stem design parameter. Shorter height, moderate thickness, and moderate slanting stem designs are recommended.

Effects of light and water availability on the growth of Aglaia duperreana seedlings.

Aglaia duperreana, a species with a long cultivation history, is of high ornamental value. To understand the growth and photosynthetic changes of A. duperreana seedlings under variable environmental conditions, we conducted an experiment with light intensities adjusted at 70%, 50% and 30%, crossed with three moisture treatments at 70%, 50% and 30% of field capacity, and a control group which maintained 90% light intensity and 90% field capacity. The results showed that both drought stress and shading propensity significantly inhibited the growth of A. duperreana seedlings, with stronger impacts from drought stress. The increments in stem height and ground diameter, net photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll content were decreased with the maximum declines by 71.4%, 81.2%, 93.2%, 71.5%, 70.6% and 30.4%, respectively. Under severe drought stress (30% of field capacity), partial shading (50% of translucency) appeared to lessen the detrimental effects of drought. The combination of 70% translucency and 70% field capacity was optimal, resulting in higher increments in stem height, leaf area, net photosynthetic rate, transpiration rate, and stomatal conductance. The maximum fluorescence, variable fluorescence, PSⅡ potential activity, and PSⅡ maximum light energy conversion efficiency increased and then decreased with decreasing moisture. These findings suggested that A. duperreana could adapt to drought and shading stress by modulating growth, enhancing chlorophyll content, and adjusting photosynthetic system. Maintaining translucency at 70% and field moisture capacity at 70% could promote photosynthesis, with positive consequences on growth of A. duperreana.

Morphological Diversity and Production of Six Sago (Metroxylon spp.) Accessions from Tana Luwu, South Sulawesi, Indonesia

Tana Luwu area owns a relatively high diversity and production potential of sago, but it has not yet been managed optimally. This study aims to identify and analyze the diversity of morphological characteristics and the production of various sago accessions in Tana Luwu. Based on morphological characteristics, the sago palm in Tana Luwu is divided into two groups by the presence of thorns on the rachis and petioles. The presence of thorns has the largest coordinate axis angles, representing a higher diversity distance than other morphological characteristics. Some accessions show very high production potential, with a total production of 476.66 kg per dry tree starch. The average sago production in the six accessions is 276.40 kg per dry tree starch. Accessions with a yield potential > 200 kg per dry starch are observed in Kapa, Uso, Kasimpo, and Sabbe. Therefore, sago in these accessions is potentially developed to obtain superior varieties. Two significant morphological characteristics that contribute to sago production are stem height (r = 0.73) and the number of leaves (r = 0.78).

Simulated drift of 2,4-D and dicamba in pecan (<i>Carya illinoinensis</i> K. Koch) and olive trees (<i>Olea europaea</i> L.)

The cultivation of pecan (Carya illinoinensis K. Koch) and olive trees (Olea europaea L.) near pasture and grain cultivation areas in southern Brazil has caused herbicide drift problems. Therefore, the objective of this study was to evaluate the phytotoxic effects of herbicides 2,4-D and dicamba on the growth of pecan and olive tree seedlings. A total of 8 underdoses were used, as follows: 0, 1.56, 3.125, 6.25, 12.0, 25.0, 50.0, and 100% of the recommended doses of herbicides 2,4-D (670 g a.e ha−1) and dicamba (720 g a.e ha−1) for burndown. The applications were carried out in 80 cm-high seedlings with the aid of a CO2 pressurized sprayer with a spray solution volume of 150 L. ha−1. The analyzed variables were phytotoxicity at 7, 14, 21, 30 and 60 days after spray (DAA) and plant height and stem diameter at 30 and 60 DAA. The drift of hormonal herbicides caused damage to the growth of pecan and olive trees, decreasing their stem diameter and height, with the herbicide dicamba showing the greatest damage. In addition, doses above 12.5% of both herbicides resulted in phytotoxicity levels greater than 60%, and doses of 50 and 100% were responsible for leaf senescence.

Allometric equations to calculate living and dead fuel loads in Mediterranean species

Determining the structure and fuel load is key to know the flammability of vegetation in the Mediterranean Basin where forest fires are frequent. Determine which plant structural variable is best related to living and dead fuel to develop allometric equations in nine species in the Western Mediterranean Basin. In the east of the Iberian Peninsula (Valencia Province), we measured four structural variables (basal stem diameter, height, maximum diameter and perpendicular diameter) that were related, by means of allometric equations, to the living and dead fuel separated into different size classes. We also analyze fuel changes across developmental states of the studied species, and the vertical distribution of dead fuel. General equations that consider all development states can be used to determine living fuel. However to obtain dead fuel, we recommend using specific equations for each development state and fuel fraction for better accuracy. The basal stem diameter was the best structural variable in almost all cases for estimating fuel in the studied species. Dead fuel load throughout species’ ontological development is a key factor to manage Mediterranean plant communities.

Effects of CO2 Treatments on Functional Carbon Efficiencies and Growth of Forest Tree Seedlings: A Study of Four Early-Successional Deciduous Species

Atmospheric CO2 levels have been increasing, and these changes may result in differential adaptive responses in both genera and species and highlight the need to increase carbon sequestration. Ecophysiological and morphological responses of four early-successional deciduous species were examined under ambient CO2 (aCO2, 400 ppm) and elevated CO2 (eCO2, 800 ppm) treatments. The four species, all of which are used in restoration, were Alnus viridis subsp. crispa (Ait.) Turrill (green alder), A. incana subsp. rugosa (Du Roi) R.T. Clausen (speckled alder), Betula populifolia (Marshall) (gray birch), and B. papyrifera (Marshall) (white birch); all are from the same phylogenetic family, Betulaceae. We examined biochemical efficiencies, gas exchange, chlorophyll fluorescence, chlorophyll concentrations, foliar nitrogen (N), and growth traits. A general linear model, analysis of variance, was used to analyze the functional carbon efficiency and growth differences, if any, among genera, species, and provenances (only for growth traits). The alders had greater biochemical efficiency traits than birches, and alders upregulated these traits, whereas birches mostly downregulated these traits in response to eCO2. In response to eCO2, assimilation either remained the same or was upregulated for alders but downregulated for birches. Stomatal conductance was downregulated for all four species in response to eCO2. Intrinsic water use efficiency was greater for alders than for birches. Alders exhibited a consistent upregulation of stem dry mass and height growth, whereas birches were somewhat lower in height and stem dry mass in response to eCO2. Foliar N played an important role in relation to ecophysiological traits and had significant effects relative to genus (alders > birches) and CO2 (aCO2 > eCO2), and a significant genus × CO2 interaction, with alders downregulating foliar N less than did birches. Covariate analysis examining carbon efficiency traits in relation to foliar N showed clear functional responses. Both species in both genera were consistent in their ecophysiological and morphological responses to CO2 treatments. There was supporting evidence that assimilation was sink-driven, which is related to a plant organ’s ability to continue to grow and incorporate assimilates. The alders used in this study are actinorhizal, and the additional available foliar N, paired with increased stem dry mass sink activity, appeared to be driving upregulation of the carbon efficiencies and growth in response to eCO2. Alders’ greater carbon efficiencies and carbon sequestration in impoverished soils demonstrate that alders, as opposed to birches, should be used to accelerate ecological restoration in a world of increasing atmospheric CO2.

Mechanisms involved in plant growth promotion by Enterobacter cloacae DJ under salinity-alkalinity stress

BackgroundPlant-promoting bacteria are safer alternatives to pesticides and fertilizers, reduce environmental pollution, and increase crop yields. We isolated an Enterobacter cloacae strain DJ with plant-promoting effects from the rhizosphere soil of a plant (Leymus chinensis (Trin.) Tzvel) in the western region of Jilin Province of China and investigated the mechanisms underlying the adaptation of the DJ bacteria to salinity-alkalinity environments and the molecular mechanisms of the cross-talk between DJ bacteria and cucumber seedlings.ResultsThe average diameter of the colonies on the salinity-alkalinity medium after incubation for 24 h was 3.3 cm, and this was significantly higher than the 1.9 cm diameter in ADF medium (p < 0.01). Comparative proteomic analysis revealed that 188 differentially expressed proteins, comprising 116 upregulated and 72 downregulated proteins, significantly changed in salinity-alkalinity groups compared to the control groups. The top one upregulated pathway of KEGG enrichment was bacterial chemotaxis, DJ bacteria adapted to salinity-alkalinity environments by upregulating the genes associated with bacterial chemotaxis. The contents of putrescine in salinity-alkalinity and control groups were 4.73 μg/mL and 3.02 μg/mL, whereas the contents of spermidine were 46.18 ng/mL and 0.34 ng/mL, respectively. Comparing to the control cohorts, the concentrations of both polyamines in the experimental cohorts exhibited statistically significant increases (p < 0.01). The expression of Pt gene encoding polyamine transporter protein was sharply up-regulated in cucumber roots after treatment with DJ bacteria under salinity-alkalinity stress; the expression was more than tenfold higher than that in the control groups. The enzyme activities of POD, SOD, and CAT in cucumber seedlings were higher compared to those in the control groups (p < 0.01). The stem height, number of lateral roots, and fresh weight of cucumber seedlings in the DJ treatment groups were 6.0 cm, 17 roots, and 0.42 g, respectively, whereas those of the control groups were 3.8 cm, 14 roots, and 0.28 g, respectively, with a notable difference between two cohorts (p < 0.01).ConclusionsDJ bacteria can live in salinity-alkalinity conditions by upregulating the expression of genes associated with chemotaxis. The resistance of cucumber seedlings under salinity-alkalinity conditions through the antioxidant pathway was increased by polyamines produced by DJ bacteria.Graphical

Chestnut blight (Cryphonectria parasitica (Murr.) Barr) disease incidence and its effect on the morphological and anatomical features of Castanea sativa trees

AbstractSweet chestnut (Castanea sativa) is an ecologically and economically valuable tree species worldwide. Various pathogens, both endemic or introduced, cause severe damage or death to chestnut trees. Chestnut blight, caused by the fungus Cryphonectria parasitica, is one of the most devastating plant diseases known which influences chestnut trees in all major cultivation regions. The work presented here aimed to investigate how the incidence of chestnut blight varied between trees growing at two altitudes (200–400 m vs. 400–600 m) and to determine the impact of chestnut blight on tree‐ring width, morphology and anatomy of C. sativa trees. The incidence of C. parasitica infections was greater at 200–400 m than at 400–600 m. Greater stem diameters were found at 200–400 m than at 400–600 m. There were no differences in stem diameters and heights, however, between healthy and C. parasitica infected chestnut trees. The anatomical characteristics of wood were also compared between healthy and C. parasitica‐infected chestnut trees. Fibre cell traits (length/width, lumen width, lumen area) were higher in healthy trees than in C. parasitica‐diseased trees. Vessel diameters were greater in infected compared with healthy trees. Tree ring widths and wood anatomical characteristics therefore were significantly influenced by C. parasitica infections.

Height–diameter allometry for a dominant palm to improve understanding of carbon and forest dynamics in forests of Puerto Rico

AbstractTropical forests play a major role in the global carbon cycle but their diversity and structural complexity challenge our ability to accurately estimate carbon stocks and dynamics. Palms, in particular, are prominent components of many tropical forests that have unique anatomical, physiological, and allometric differences from dicot trees, which impede accurate estimates of their aboveground biomass (AGB) and population dynamics. We focused on improving height estimates and, ultimately, AGB estimates for a highly abundant palm in Puerto Rico, Prestoea acuminata. Based on field measurements of 1003 individuals, we found a strong relationship between stem height and diameter. We also found some evidence that height–diameter allometry of P. acuminata is mediated by various sources of environmental heterogeneity including slope and neighborhood crowding. We then examined variability in AGB estimates derived from three models developed to estimate palm AGB. Finally, we applied our novel height:diameter allometric model to hindcast dynamics of P. acuminata in the Luquillo Forest Dynamics Plot during a 27‐year period (1989–2016) of post‐hurricane recovery. Overall, our study provides improved estimates of AGB in wet forests of Puerto Rico and will facilitate novel insights to the dynamics of palms in tropical forests.Abstract in Spanish is available with online material.

Effect of drought stress on the physiology and early growth of seven Senegalia (Acacia) Senegal (L.) Britton provenances

Decline of Senegalia senegal (Acacia senegal) in its natural range has been observed and attributed mainly to harsh environmental conditions such as frequent drought occurrences. The objective of this study is to assess the effect of water stress on growth, biomass allocation and photosynthetic capacity in Senegalia senegal seedlings. Seeds were collected from seven provenances in Senegal and grown under greenhouse conditions in a randomized complete block design with 5 replications. Seedlings were subjected to three cyclic droughts by watering them when average soil moisture content dropped to 4.7%, 2.7%, and 2.1% during the first, second, and third dry down cycles, respectively. With the exception of net photosynthetic rate, stomatal conductance and transpiration at the second and third dry down cycles, no drought by provenance interaction was found for any trait measured. Ngane provenance had a lower root/shoot ratio and allometric analysis revealed that Ngane allocated less biomass to roots than shoots. Ngane developed superior growth traits and biomass production, despite similar net photosynthetic rate with other provenances before treatments started. Overall, drought stress significantly reduced biomass, stem height, diameter and leaf gas exchange. Total biomass was reduced by 28.5%, whereas root/shoot ratio was increased by 25% compared to control. Significant interaction on leaf gas exchanges at the second and third dry down cycles reveals different sensitivity levels to drought among provenances with the Ranerou provenance exhibiting no decline in leaf gas exchange. No significant difference of stomatal limitation among genotypes was found, which is indicative of the complex process of photosynthesis and the need for extended times scales for measurements to better depict physiological sensitivity of Senegalia senegal to drought.

Scientific basis of approval of planting periods and standards of winter barley varieties in rainfall lands

This article analyzes stem height, crop structure, productivity and effect on grain quality of barley varieties. According to the results of the experiment, it was noted that the highest plant height in the full ripening phase of Lalmikor and Mushtarak varieties of barley was 62.8-64.6 cm and 62.4-64.1 cm in the early (October 15) planting period. In both varieties, stem height resulted in lower plant height with delayed planting dates. The decrease in the planting rate caused the plant to grow taller. In all planting periods, the plant height was the highest in the option with 2.0 million grains/ha of seeds, and the shortest in the option with 3.0 million grains/ha of seeds. The number of productive stems in the Lalmikor variety was from 176.1 to 235.2 grains per 1 m2, and this indicator was 12.7 to 8.4 more than the Mushtarak variety. While the number of productive stems per 1 m2 was the highest 235.2 in the Lalmikor variety, when the sowing rate was 2.5 million grains/ha and planting time on October 30, 226.8 grains were observed in the Mushtarak variety, in which 3.0 million grains/ha of seeds were used on October 15.

Annual dynamics of ammonium and nitrate nitrogen content by using capsulated carbamide in cassettes of one-year-old seedlings of Scots Pine (Pinus sylvestris)

Over the past decades of forestry development in Russia, the main trends have been identified, according to which P. sylvestris planting material can be effectively grown in a container method with a closed root system, considering the forest-seed area. The purpose of the study was to study the annual dynamics of ammonium and nitrate nitrogen in a soil with P. sylvestris with a closed root system using encapsulated urea with hydroquinone and mulch. The objectives of the study were based on the study of the effect of mineral fertilizers on the annual dynamics of ammonium and nitrate nitrogen and their effect on the growth of seedlings. The object of the study was the dynamics of the content of these nitrogen compounds in the soil. The study was carried out by methods of agrochemical, biometric and statistical analysis. Thus, the use of extended-form carbamide makes it possible to cover the need of plants for nitrogen nutrition throughout the growing season, having a significant impact on their growth in stem height. The use of encapsulated carbamide with hydroquinone, 0.5 cm pine mulch, potassium monophosphate and phosphorous flour allows the production of the best P. sylvestris seedlings with a maximum height of 188.82±15.41 mm per year due to constant saturation of the soil with available nitrogen, on which a change in the growth rate of seedlings is almost directly dependent (R = 0.99821-0.99988; Multiple R = 0.99643-0.99977; Adjusted R = 0.98928-0.99930; p &lt; 0.01525-0.05978). At the same time, ammonium nitrogen has the greatest effect on it (p &lt; 0.01633-0.05436).

VALUATION OF THE INFLUENCE OF ENCAPSULATED MINERAL FERTILIZERS ON PLANT GROWTH KINETICS

The work investigated the effect of encapsulated mineral fertilizers on the growth and development of plants for 45 days. As a mineral fertilizer, nitroammophoska was used, which was encapsulated by a shell of different compositions: sample KD1 – a mixture of polystyrene, lignin, and carbon; sample KD2 – a mixture of polystyrene, lignin, and zeolite. The bioindication method was used to determine the effect of encapsulated mineral fertilizers on plant growth kinetics. Based on the study's results, the average rate of germination of ryegrass in the experimental samples and the average rates of the main plant parameters (stem height, root length, plant weight) were determined. It was established that the highest rate of germination was in the sample with encapsulated mineral fertilizer KD1 — 100%, and the lowest in the sample GD — 85%. The highest average indicators of measurement of the main parameters of ryegrass were in samples KD1 and KD2. The highest average indicators of measurement of the main parameters of ryegrass were in samples KD1 and KD2, and the lowest in the control sample (soil). It was established that on the 45th day, the mineral fertilizer in the KD1 sample was fully absorbed by the plants.

Nanocellulose/wood ash-reinforced starch-chitosan hydrogel composites for soil conditioning and their impact on pea plant growth.

Hydrogels are 3-dimensional polymer networks capable of absorbing a large amount of water. Natural polymeric hydrogels are biodegradable, non-toxic and biocompatible. They can effectively retain nutrients for the plant and can be used as soil conditioners. This study uses a chemical cross-linking technique to synthesize starch and chitosan-based hydrogel using citric acid as a cross-linker. Additionally, hydrogel composites were developed by incorporating wood ash, nano-cellulose, and NPK (nitrogen-phosphorus-potassium) fertilizer as fillers to enhance their properties. The formulated hydrogel/hydrogel composite samples were characterized by FTIR spectroscopy, SEM analysis, X-ray diffraction and thermo-gravimetric analysis. The experiment results showed the chemical cross-linking among the polymeric chain and the semi-crystalline nature of the hydrogel/hydrogel composite samples. The swelling capacity of the hydrogel/hydrogel composite samples was 200-420% (in distilled water) and 104-220% (in saline medium) and demonstrated biodegradability within 110 days. The NPK reinforced hydrogel composite showed an excellent effect on the growth of pea plants (leaves count = 37, stem height = 20.2 cm), and could be effectively used as soil conditioners for agricultural applications. Considering the ability of hydrogel composites to reduce irrigation needs, enhance nutrient retention, and improve crop production, these novel hydrogel composites present an economically viable solution for sustainable agricultural practices.

The inadequacy of current carbon storage assessment methods for rewilding: A Knepp Estate case study

Abstract In the context of global climate change mitigation, carbon storage in woody vegetation plays a crucial role. Recognising the value of the i‐Tree Eco model for carbon storage in urban and forestry settings, this study aimed to explore its applicability to rewilded landscapes. Using direct measurements from destructively sampled scrub from the Knepp Estate, our goal was to determine the model's suitability to this landscape. Our findings reveal that these methods are not appropriate for multi‐stemmed trees below browsing height, as we observed no significant relationship between stem basal diameter and height. The i‐Tree tool's assumption of below‐ground biomass being 26% of above‐ground biomass may not be applicable to herbivore‐influenced landscapes. Additionally, we found that, on average, scrub at Knepp had more biomass below the ground than above, with a root:shoot ratio of 1.07, which is more than four times the amount predicted by current models using the 0.26 estimate ratio. This study underscores the need for novel allometric approaches that consider species‐specific biomass and the impact of external factors, such as herbivory, on carbon storage. Accurate carbon accounting in future rewilding projects is essential for their contribution to both biodiversity enhancement and climate change mitigation. While the i‐Tree Eco model provides valuable insights for many ecosystems, our findings suggest that its applicability may be limited in scrubland ecosystems, especially in rewilded landscapes where natural processes create semi‐stable scrub and open wood pastures. Nonetheless, with suitable adjustments or when complemented with other methods, the i‐Tree Eco model could be a valuable tool for specific scrub or rewilding scenarios.

Atributos das árvores hospedeiras, e não a diversidade da comunidade, conduzem a abundância de epífitas em florestas tropicais sazonais

Abstract Epiphytes are considered indicators of forest ecological integrity, but the factors that explain their abundance are still not well understood. We here evaluated tree colonization by epiphytes in old-growth monospecific reforestation stands of Astronium urundeuva (M.Allemão) Engl. (Anacardiaceae) and Eucalyptus saligna Sm. (Myrtaceae), in comparison to a neighbor seasonal tropical forest fragment under similar environmental conditions. In each forest type, we identified and measured all trees (planted and colonizers) from 5-cm stem diameter in five 200 m² plots and quantified all vascular epiphytes per tree. Tree species were categorized by bark roughness, canopy deciduousness and growth rate. The abundance of epiphytes and the frequency of host trees were higher in the A. urundeuva plantation than in the native forest, with the E. saligna stand in an intermediate position. Also, we found that host traits influenced the abundance of epiphytes in their trunks. Host trees had average stem perimeter and height both higher than non-hosts, which indicates that colonization is more likely to occur in older trees. The average abundance of epiphytes per tree was higher in species with rough bark, but no relationship was found with canopy deciduousness or tree growth rate. We evidenced, therefore, that forest plantations, even if monospecific, can provide habitat for epiphytes. However, at community level, colonization success, either in native or restored forest, depends on the relative abundance of species whose bark type favors epiphytes establishment.

Mechanically induced localisation of SECONDARY WALL INTERACTING bZIP is associated with thigmomorphogenic and secondary cell wall gene expression.

Plant growth requires the integration of internal and external cues, perceived and transduced into a developmental programme of cell division, elongation and wall thickening. Mechanical forces contribute to this regulation, and thigmomorphogenesis typically includes reducing stem height, increasing stem diameter, and a canonical transcriptomic response. We present data on a bZIP transcription factor involved in this process in grasses. Brachypodium distachyon SECONDARY WALL INTERACTING bZIP (SWIZ) protein translocated into the nucleus following mechanostimulation. Classical touch-responsive genes were upregulated in B. distachyon roots following touch, including significant induction of the glycoside hydrolase 17 family, which may be unique to grass thigmomorphogenesis. SWIZ protein binding to an E-box variant in exons and introns was associated with immediate activation followed by repression of gene expression. SWIZ overexpression resulted in plants with reduced stem and root elongation. These data further define plant touch-responsive transcriptomics and physiology, offering insights into grass mechanotranduction dynamics.

Influence of Explants Type, Nodal Positions and Two Cytokinins on Cassava (Manihot esculenta, Crantz) In vitro Organogenesis

Cassava In vitro regeneration is essentially influenced by exogen factors as well as explants nature. This work aimed to evaluate explants type and positions influence, phytohormone on cassava plantlets regeneration in modified MS media. The apex and nodes of the position 3, 5, and 7 were initiated on Murashige and Skoog (MS) based media supplemented with Gamborg B5 vitamins and growth regulators such as naphthalene acetic acid (NAA), 6-benzylaminopurine (BAP) and zeatin (ZEAT) in different concentrations. The results indicated a significant difference (p=0.0001) among explants sprouted regarding the nodes position and the cultivar genotype during the time of culture. The highest rate of regenerated plantlets was found with nodes of position 5 (95.33%) followed respectively by nodes of the position 7 (93.33%), nodes of the position 3 (89.33%), and the apex (76%). Regarding the growth regulators, NAA (0.5 mg/l) + BAP (0.5 mg/l) combination was favorable for height growth (26.2cm), and leaves development (7.84 cm) in most of cultivars, whereas NAA (0.5 mg/l) + ZEAT (0.5 mg/l) combination was more favorable to rhizogenesis in overall cultivars. Among the cultivars, the best performance in stem height (26.2 cm), in leaf length (7.84 cm), and roots number (4.64) were observed with INA 1er cultivar. The cultivars RB89509, BEN 86052, and DOKU were less grown on MS supplemented with 0.5 mg/l of BAP or ZEAT. These findings could contribute of using nodes of the positions 5, 7 as potential explants and Zeatin for cassava plantlets rhizogenesis.