Leaf Blade Thickness Research Articles

Integrated Ca, Mg, Cu, and Zn supply upregulates leaf anatomy and metabolic adjustments in Eucalyptus seedlings

Adaptive responses to abiotic stresses such as soil acidity in Eucalyptus—the most widely planted broad-leaf forest genus globally—are poorly understood. This is particularly evident in physiological and anatomical disorders that inhibit plant development and wood quality. We aimed to explore how the supply of Ca and Mg through liming (lime), combined with Cu and Zn fertilization (CZF), influences physiological and anatomical responses during Eucalyptus grandis seedlings growth in tropical acid soil. Therefore, related parameters of leaf area and leaf anatomy, stomatal size, leaf gas exchange, antioxidant system, nutrient partitioning, and biomass allocation responses were monitored. Liming alone in Eucalyptus increased specific leaf area, stomatal density on the abaxial leaf surface, and Ca and Mg content. Also, Eucalyptus exposed only to CZF increased Cu and Zn content. Lime and CZF increased leaf blade and adaxial epidermal thickness, and improved the structural organization of the spongy mesophyll, promoting increased net CO2 assimilation, and stomatal conductance. Fertilization with Ca, Mg, Cu, and Zn positively affects plant nutrition, light utilization, photosynthetic rate, and antioxidant performance, improving growth. Our results indicate that lime and CZF induce adaptive responses in the physiological and anatomical adjustments of Eucalyptus plantation, thereby promoting biomass accumulation.

ANATOMICAL STRUCTURE OF THE LEAFS OF ORNAMENTAL STONECROPS OF THE GENERA SEDUM L. AND HYLOTELEPHIUM H. OHBA UNDER CONDITIONS OF DIFFERENT LIGHT LEVELS

The paper presents the results of determining the quantitative and qualitative characteristics of the anatomical structure of the leaf of the ornamental stonecrops of the genera Sedum L. and Hylotelephium H. Ohba during the seasonal development at different levels of illumination in the conditions of the Kryvyi Rih Botanical Garden of the NAS of Ukraine, which is located in the steppe zone of Ukraine (arid agroclimatic zone).The objects of the study were the plants Hylotelephium ewersii, Hylotelephium spectabile, Sedum album, Sedum reflexum and Sedum spurium. Research was carried out on sites with different levels of illumination: a well-lit place of growth (control site) - the level of illumination at lunchtime reached 39,000–56,500 lux in clear weather and 14,500–23,500 lux on an overcast day; shadow area - the light level at lunch time in clear weather reached 2,500-3,500 lux, and on an overcast day 1,200-2,000 lux. The research was conducted in three stages: the end of May, the end of July, and the end of September. We used 5 individuals of each species, which were grown in open ground (ordinary black soil) at a natural level of moisture supply. Anatomical studies were performed on live specimens using standard methods. The material for the studies was preparations of morphologically mature leaves taken from the middle tier of individuals. It was found that during the seasonal development of plants, changes occur in the anatomical structure of leaves. In plants of H. ewersii, H. spectabile, S. reflexum and S. spurium, leaf thickness was greater in conditions of sufficient light and there was a decrease in leaf blade thickness during seasonal development (from May to September), both in the sun and in the shade. Under conditions of shade at the end of the season, leaf thickness decreased most significantly in H. spectabile and S. spurium - almost twice. On the other hand, in S. spurium, under insufficient lighting, the thickness of the lower and upper epidermis increased more than twice, and in H. spectabile, the thickness of the cuticle increased in both variants of the experiment - in the sun by 2.1 times, in the shade by 1.4 times. In stonecrops with flat leaves, the diameter of the central conducting bundle during the season in sunny conditions was 26 % (S. spurium) – 52 % (H. spectabile) larger than in the shade. Only in S. album, from May to September, leaf thickness and the diameter of the central conductive bundle, in absolute terms, were larger in the shade than in the sun. The obtained results indicate high plasticity of the studied species and peculiarities of phenotypic changes in the anatomical structure of leaves. Key words: family Crassulaceae, leaf anatomy, light level, steppe zone, Krуvorіzhzhуа, seasonal development

Morphophysiological changes of Acca sellowiana (Myrtaceae: Myrtoideae) saplings under shade gradient.

Understanding morphological and physiological changes under different light conditions in native fruit species in juveniles' stage is important, as it indicate the appropriate environment to achieve vigorous saplings. We aimed to verify growth and morphophysiological changes under shade gradient in feijoa (Acca sellowiana (O. Berg) Burret) to achieve good quality saplings adequate to improve cultivation in orchards. The saplings were grown for twenty-one-month under four shading treatments (0%, 30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy parameters were evaluated. Saplings under full sun and 30% shade had higher height and diameter growth and dry mass accumulation due to higher photosynthesis rate. As main acclimatization mechanisms in feijoa saplings under 80% shade were developed larger leaf area, reduced leaf blade thickness, and enhanced quantum yield of photosystem II. Even so, the net CO2 assimilation and the electron transport rate was lower and, consequently, there was a restriction on the growth and dry mass in saplings under deep shade. Therefore, to obtain higher quality feijoa saplings, we recommend that it be carried out in full sun or up to 30% shade, to maximize the sapling vigor in nurseries and, later, this light environment can also be used in orchards for favor growth and fruit production.

Biogeochemical and microscopic studies of soil and Phragmites australis (Cav.) Trin. ex Steud. plants affected by coal mine dumps.

Developed areas of the coal industry are subjected to long-term anthropogenic impacts from the input and accumulation of overburdened coal material, containing potentially toxic heavy metals and metalloids (HMM). For the first time, comprehensive studies of soils and plants in the territory of the Donetsk coal basin were carried out using X-ray fluorescence, atomic absorption analysis, and electron microscopy. The observed changes in the soil redox conditions were characterized by a high sulfur content, and formations of new microphases of S-containing compounds: FeS2, PbFe6(SO4)4(OH)12, ZnSO4·nH2O, revealed the presence of technogenic salinization, increased Сorg content, and low pH contents. Exceedances of soil maximum permissible concentrations of Pb, Zn, Cu, and As in areas affected by coal dumps were apparent. As a consequence of long-term transformation of the environment with changes in properties and chemical pollution, a phytotoxic effect was revealed in Phragmites australis (Cav.) Trin. ex Steud, accompanied by changes in ultrastructural and organization features of roots and leaves such as increases in root diameters and thickness of leaf blades. The changes in the ultrastructure of cell organelles: a violation of the grana formation process, an increase in the number of plastoglobules, a decrease in the number of mitochondrial cristae, and a reduction in the electron density of the matrix in peroxisomes were also observed. The accumulation of large electron-dense inclusions and membrane fragments in cell vacuoles was observed. Such ultrastructural changes may indicate the existence of a P. australis ecotype due to its long-term adaptation to the disturbed environment.

EVALUACIÓN DE DAÑO POR Spodoptera frugiperda (J.E. SMITH) (LEPIDOPTERA: NOCTUIDAE) Y CARACTERIZACIÓN DE LOS RASGOS MORFOLÓGICOS FOLIARES EN POBLACIONES CRIOLLAS DE MAÍZ (Zea mays L.)

<p><strong>Background.</strong> The fall armyworm <em>Spodoptera frugiperda </em>is one of the most damaging pests of maize in tropical areas. <strong>Objective.</strong> To evaluate the damage caused by <em>S. frugiperda</em> and the leaf morphological traits in 15 populations of maize landrace. <strong>Methodology.</strong> The leaf damage caused by <em>S. frugiperda</em> and four-leaf morphological traits (leaf blade thickness, leaf blade hardness, specific leaf area and trichome density) were evaluated at 20, 30 and 40 days after emergence (DAE) in two seasons, dry (March and April) and rainy (June and July). Spearman correlation between the degree of leaf damage and each leaf morphological trait was also evaluated. <strong>Results.</strong> Maize populations showed differential response to the damage caused by <em>S. frugiperda</em> among seasons and evaluating date. The leaf morphological traits were different between seasons and among evaluating dates. The trichome density had intermediate negative correlation with the level of leaf damage in rainy season (<em>r<sub>s</sub></em> = − 0.32,<em> p</em> < 0.001). <strong>Implications.</strong> The lower leaf damage may be indicator of resistance against <em>S. frugiperda</em>. <strong>Conclusion.</strong> The population 2020−M62 had low susceptibility to <em>S. frugiperda</em>, this population may be candidate for maize breeding program.</p>

Morphoanatomical Changes in Eucalyptus grandis Leaves Associated with Resistance to Austropuccinia psidii in Plants of Two Ages.

The fungus Austropuccinia psidii infects young tissues of Eucalyptus plants until they are two years old in the nursery and field, causing Myrtaceae rust. The characteristics making older eucalypt leaves resistant to A. psidii and the reason for the low levels of this pathogen in older plants need evaluations. The aim of this study was to evaluate the morphological differences between Eucalyptus grandis leaves of different growth stages and two plant ages to propose a visual phenological scale to classify E. grandis leaves according to their maturation stages and to evaluate the time of leaf maturation for young and adult plants. A scale, based on a morphological differentiation for E. grandis leaves, was made. The color, shape and size distinguished the leaves of the first five leaf pairs. Anatomical analysis showed a higher percentage of reinforced tissue, such as sclerenchyma-like tissue and collenchyma, greater leaf blade thickness, absence of lower palisade parenchyma in the mature leaves and a higher number of cavities with essential oils than in younger ones. Changes in anatomical characteristics that could reduce the susceptibility of older E. grandis leaves to A. psidii coincide with the time of developing leaf resistance. Reduced infection of this pathogen in older plants appears to be associated with a more rapid maturation of their leaf tissues.

QUANTITATIVE AND QUALITATIVE INDEXES OF THE FUNCTIONING OF PHOTOSYNTHETIC APPARATUS OF ORNAMENTAL SUNFLOWER PLANTS WITH DIFFERENT SEEDING RATES UNDER CONDITIONS OF THE SOUTHERN STEPPE OF UKRAINE

The research revealed the tendency for an increase in the index of the average area of an individual leaf blade when the seeding rate rose from 50 to 60 thous. pcs./ha, and further there was a reduction in this index when the seeding rate increased to 70 thous. pcs./ha. The average index in the variant of the hybrid Teddy F1 was 72.6 cm<sup<2</sup<, Double Sunking F1 - 70.3 cm<sup<2</sup<, Santa Fe F1 - 70.8 cm<sup<2</sup<, respectively. The dependence of the index of leaf blade thickness of sunflower hybrids on the factors under study was analogous: this index was minimal in the variant of the hybrid Teddy F1 - 0.58 mm, it fell to 0.55 mm in the variant of the hybrid Double Sunking F1, it was minimal in the variant of the hybrid Santa Fe F1 - 0.52 mm on the average by Factor В. According to our data, the dependence of the intensity of green color of a leaf blade of sunflower hybrids was similar: this index was not essentially dependent on Factor А, but an increase in the seeding rate caused a reduction in the intensity of green color of leaves in comparison with the sample. If the intensity of the sample color is considered to be 100%, the color of a leaf blade in the variant of the hybrid Teddy F1 was at the level of 73%, that of the hybrid Double Sunking F1 - 69%, and that of the hybrid Santa Fe F1 - 69% of the sample. The least intensity of green color of sunflower leaves was with the maximum seeding rate and did not exceed 62% on the average by Factor А. On the average by Factor В, the hybrid Teddy F1 was considered to be a leader by the content of green pigment in its leaves - 8.69 mg/g, in the variant of the hybrid Santa Fe F1 it was 7.45 mg/g, Double Sunking F1 - 8.02 mg/g. The maximum area of the crop photosynthetic apparatus was formed in the variant of the hybrid Teddy F1 being 30.7 thous. m2/ha at the stage of flowering, in the variant of the hybrid Double Sunking F1 - 29.5 thous. m<sup<2</sup</ha and in the variant of the hybrid Santa Fe F1 - 26.1 thous. m<sup<2</sup</ha, respectively. In all the variants of the crop hybrids there was a correlation according to which there was an increase in the index of leaf surface area when the seeding rate rose from 50 to 60 thous. pcs./ha, and when there was a further increase in the seeding rate to 70 thous. pcs./ha, vice versa, this index started decreasing considerably. The index of net productivity of photosynthesis reached its maximum values in the variant of the hybrid Teddy F1 being 1.99 g/m<sup<2</sup</day, on the average by Factor В, that of the hybrid Double Sunking F1 - 1.93 g/m<sup<2</sup</day and that of the hybrid Santa Fe F1 - 1.84 g/m<sup<2</sup</day, respectively.

Change in leaf anatomy, physiology, and essential oil of Varronia curassavica Jacq. accessions under two light conditions

The aim of this study was to evaluate the effect of light on anatomy, physiology and essential oil content and composition of Varronia curassavica. They were analysed two light conditions (full sunlight and protected environment with 50% shade screen) and five accessions (VCUR-101, VCUR-102, VCUR-201, VCUR-302, VCUR-802). V. curassavicacultivated in full sun presented a greater development of the leaf blade and palisade parenchyma thickness for all accessions. Chlorophyll levels did not differ according to the two light environments. The leaf area was larger in the protected environment. The essential oil yield of the accessions ranged from 0.26 to 0.87 mL/plant in full sun and from 0.34 to 0.53 mL/plant in the protected environment. The composition of the essential oil was influenced by the light and the accession. All accessions presented (E)-caryophyllene and α-humulene. The influence of light on the evaluated variables is genotype dependent.

High-throughput in vitro propagation and evaluation of foliar micro-morpho-anatomical stability in Musa acuminata cv. ‘Grand Nain’ using 6-benzoyladenine (BOA) in the nutrient medium

The present study was intended to develop an effective micropropagation system of the economically important ‘Grand Nain’ variety of Musa acuminata Colla (AAA) having high structural fidelity and significant potential to multiply shoots under in vitro conditions using the non-conventional cytokinin 6-benzoyladenine (BOA, C12H9N5O). The young sword sucker explants were cultured on MS medium supplemented with 4.0 mg L − 1 of BOA and 2.0 mg L − 1 IAA resulted in the formation of 6.0 shoots (3.8 cm length) within 21 days. Cytokinins with NAA resulted in callus development and stalled the shoot development. Further subculturing of shoots on MS medium containing 6.0 mg L − 1 of BOA and 2.0 mg L − 1 IAA had a significant influence on overall shoot multiplication and elongation (36.2 shoots with 7.0 cm length after 3rd subculture), while 6.0 mg L − 1 of 6-benzylaminopurine (BAP, C12H11N5) and 2.0 mg L − 1 IAA produced only 20.0 shoots. The use of BOA increased the content of the photosynthetic pigments and shoots biomass. A comparative foliar micro-morpho-structural assessment revealed that the leaves derived from BOA and IAA combination had greater leaf blade thickness, well-differentiated mesophyll tissues, larger air cavities, and developed vascular tissues. Indole-3-butyric acid (IBA) was found to be more effective in root induction than α-naphthalene acetic acid (NAA) and the highest root induction (100% response, 11.0 roots with 5.5 cm length) per shootlet was detected on MS medium augmented with 2% sucrose, 50 mg L − 1 Activated charcoal and 2.0 mg L − 1 IBA. The primary hardening of plantlets was accomplished using cocopeat, and 96.5% of the plantlets survived after secondary hardening in garden soil and vermicompost mixture under ex vitro conditions. In conclusion, the use of BOA in the medium improved the quantitative and qualitative morphometric attributes of Musa acuminata cv. ‘Grand Nain’ increasing the survival rate of in vitro raised plantlets under field conditions.

Structural plasticity in leaves of Schinus terebinthifolius (Anacardiaceae) populations from three contrasting tropical ecosystems1

Schinus terebinthifolius Raddi (Anacardiaceae) is a pioneer tropical species that has been largely used in Brazil for land restoration. The species occurrence encompasses inland ecosystems such as the neotropical savanna (cerrado sensu stricto; Cerrado domain) through coastal ecosystems such as mangroves and the restinga (Atlantic Forest domain), all of which are characterized by environmental factors that highly contrast with one another. We analyzed the leaf anatomy of S. terebinthifolius populations from those three ecosystems aiming to verify whether any particular trait would provide the species with foliar anatomical plasticity, thereby enabling it to adapt to such environmentally disparate areas. We found that thickness of the leaf blade, adaxial palisade parenchyma, and spongy parenchyma differed significantly among the three ecosystems. The population from the restinga, an open, coastal ecosystem subjected to high light incidence, showed the highest means for these variables, followed by the populations from mangrove and cerrado. Leaf blade thickness in the restinga population was higher due mainly to increased palisade parenchyma thickness. The adaxial palisade parenchyma thickness in mangrove individuals was more than double the one in the cerrado population. The abaxial palisade parenchyma thickness showed no difference between the mangrove and restinga populations, yet in those two it was higher than in the cerrado population. Schinus terebinthifolius was revealed to have high potential of acclimating to different ecosystems, owing to a high capacity of developing anatomical responses to distinct stress conditions imposed by the surrounding environment, which confirms the species high phenotypic plasticity. Such high capacity of acclimating to contrasting environmental conditions by means of modulating the thickness of different leaf tissues could provide the species with an adaptive advantage in a climate-change scenario.

Morpho-anatomical, biochemical and molecular genetic responses of canola (Brassica napus L.) to sulphur application

Brassica napus (canola), a major economic crop in Egypt, contains much oils and proteins. In the present study, the foliar applications of ammonium sulphate (A.S.) [(NH4)2SO4] (0, 1% 0.2% and 0.3%) to canola plants had distinctive impacts on the morpho-anatomical, biochemical, and molecular genetic responses. Interestingly, there is a positive impact when sulphur (S) is foliarly applied at 0.2% of A.S. as revealed in antioxidants, flavonoids, total carbohydrates, and protein contents which were significantly affected. On the other hand, higher levels of glucosinolates were recorded for 0.3% and 1% A.S. (4.838 and 1.905, respectively). The electrophoretic analysis of proteins displayed 51 bands of molecular weights ranging from 8.555 to 240.6 kDa with 88.24% polymorphism with a mean band frequency of 0.373. Cytotoxicity assay revealed that the lower cell death was detected in treated root tips of canola plants following 0.2% A.S. treatment, as compared to control. With increasing of sulphur treatment, the root cortex thickness, number of conducting elements, and pericycle thickness decreased while root pith area increased. In canola leaves of high S level, the leaf blade thickness, the thickness of abaxial and adaxial epidermis surface, mesophyll thickness, and metaxylem area increased, while the xylem conducting elements number decreased. Moreover, SCoT molecular markers have been used to evaluate the genetic variation among Brassica napus genotypes subjected to different A.S. treatments. Four of the seven SCoT primers were revealed to be polymorphic in both treated and untreated samples. A total of 39 amplicons, ranging in size from 200 to 1080 bp, were amplified, with 9 (23.07%) of them being polymorphic. Clustering dendogram based on SCot markers data divided Brassica genotypes into two main clusters based on similarity coefficients indices. B. napus treated with 0.2% A.S. was separated in a distinct cluster. Furthermore, treatments with sulphur enhanced the activity of antioxidant enzymes as well as the expression level of their encoding genes (CAT, catalase; POD, peroxidase; APX, ascorbate peroxidase; SOD, superoxide dismutase; GR, glutathione reductase), particularly at 1% and 0.2% A.S. treatments. Taken together, this study revealed that foliar application of sulphur treatments, particularly at 0.2%, have a great potential to improve canola crop.

CITOCININA E VEDAÇÃO DE FRASCOS AFETAM A PROLIFERAÇÃO DE GEMAS E O DESENVOLVIMENTO In Vitro DE MICROESTACAS DE Jacaranda cuspidifolia MART.

ABSTRACT Plant growth regulators (PGRs) and types of flasks sealing that allow gas exchange can favor the development of in vitro plant propagation systems. The objective of the present study was to evaluate the eff ects of cytokinin supplementation on the induction of shoot proliferation and the influence of gas exchange on the in vitro development of Jacaranda cuspidifolia Mart microcuttings. Nodal segments were cultured in medium supplemented with diff erent concentrations (0.25; 0.5; 1.0 and 2.0 mg L-1) of 6-benzyladenine (BA). In the control treatment, there was no addition of PGRs. After 30 days of culture, the microcuttings were isolated and transferred to a rooting medium supplemented with 1.0 mg L-1 indole-3-butyric acid. At this stage, the culture fl asks were sealed with rigid polypropylene lids with a porous membrane (1 M; 21 μL L-1 s-1 CO2) or with no membrane (0 M; 14 μL L-1 s-1 CO2). Cytokinin supplementation induced the activation of axillary buds of J. cuspidifolia. The highest numbers of shoots were observed in explants cultivated in the presence of 0.5–1.0 mg L-1 BA. The microcuttings kept in flasks with a higher level of gas exchange (1M) had a higher percentage of rooting and greater root and shoot lengths. Microscopic analysis showed a greater differentiation of leaf tissues in plants kept in flasks with a higher level of gas exchange (1M). These plants also showed greater mesophyll thickness and, consequently, greater leaf blade thickness. The results provide new information for establishing an efficient in vitro propagation system for J. cuspidifolia.

Infestation of the gall midgeDasineura oleaeprovides first evidence of induced plant volatiles in olive leaves

In this study, we present the first characterization of herbivore-induced plant volatiles (HIPVs) released from infested olive leaves. The gall midge Dasineura oleae is a specific pest of Olea europaea and endemic of the Mediterranean Basin, an area in which severe outbreaks currently occurred. Little is known about the damage caused by the pest and the relationship with its host. Since gall formation and larval feeding activity may lead to the release of specific plant volatile compounds, we investigated the volatile profiles emitted from infested plants compared with healthy plants under both laboratory and field conditions. Additionally, the volatiles emitted from mechanically damaged plants were considered. A blend of 12 volatiles was emitted from olive trees infested by D. oleae. Of these, β-copaene, β-ocimene, cosmene, unknown 1 and unknown 3 were found to be exclusively emitted in infested plants. The emission of germacrene-D, (E,E)-α-farnesene, and (Z,E)-α-farnesene, α-copaene, (E)-4,8-dimethylnona-1,3,7-triene, (E)-β-guaiene and heptadecane significantly increased in infested trees. Linalool, β-copaen-4-α-ol, β-bourbonene, β-cubebene, β-elemene, β-copaene and δ-amorphene were found only in the field trial and showed differences depending on the level of infestation and the plant stage. (Z)-3-Hexenol, (E)-4-oxohen-2-enal, and 2-(2-butoxyethoxy)-ethanol, were exclusively emitted from the leaves after mechanical damage. In a field trial in Italy, we also demonstrated spring synchronization between adults of D. oleae and O. europaea trees. Analyses of morphoanatomical malformations of gall leaves showed that tissue alterations occur at the spongy parenchyma causing an increase of the leaf blade thickness. We speculate that tissue alterations may lead to HIPV release, in turn potentially attracting D. oleae natural enemies.

Dynamic of recovery growth of intercropped soybean after maize harvest in maize–soybean relay strip intercropping system

AbstractRecovery growth is common in relay intercropping systems and is a useful practice to increase total productivity of these systems. A field experiment was conducted during 2014–2016 to investigate the phenotypic and physiological traits related to light interception and utilization changes and cultivars difference of soybean during the recovery growth period. Two cropping patterns (maize–soybean relay strip intercropping (RSI), analogous soybean monoculture (CK)) and two soybean cultivars (shade‐tolerant Nandou12 and shade non‐tolerant Jiuyuehuang) were evaluated. During the co‐growth period, the growth of both two soybean cultivars was suppressed and showed a series of shade avoidance traits. After maize harvest, the LAI and leaflet number of intercropped soybean exhibited rapid growth, the LAI of Nandou12 (3.09) and Jiuyuehuang (1.32) recovered to 79% and 43% of corresponding CK level, respectively. Subsequently, final biomass of Nandou12 (3972.7 kg ha−1) and Jiuyuehuang (2263.3 kg ha−1) recovered 85.7% and 52% of corresponding CK level, respectively. Leaf blade thickness of Nandou12 recovered to the corresponding CK level, while Jiuyuehuang was not. Pn recovered to 84.5% and 82.8% of sole Pn at 80 days after soybean sowing in 2015 and to 72% and 91.2% at 66 days after soybean sowing in 2016 for Nandou12 and Jiuyuehuang, respectively. The above recovery process promoted the recovery of pod formation and grain yield. The yield of Nandou12 (1159.5 kg ha−1) has no significant difference between the CK level (1325.5 kg ha−1) but significantly higher than that of Jiuyuehuang (566.8 kg ha−1). Taken together, some recovery growth did occur in Jiuyuehuang, but it did not completely compensate for the growth reduction that occurred during the co‐growth period. Shade‐tolerant soybean cultivar has more stronger recovery growth ability in LAI, leaflet number, leaf thickness, and photosynthesis after maize harvest, which promoted the recovery growth of aboveground biomass and grain yield.

Minimum temperature drives community leaf trait variation in secondary montane forests along a 3000-m elevation gradient in the tropical Andes

ABSTRACT Background: Leaf functional traits (LFT) influence resource acquisition and are important for understanding ecosystem processes. Climate and land use are key filters of community composition and LFT, however, how the relative importance of these filter changes with elevation has been little studied in the Andes. Aims: To gain insight into the functional response of Andean forests to climate and disturbance in naturally regenerated forest stands. Methods: We measured leaf blade thickness (LBT), leaf area (LA), specific leaf area (SLA), and leaf dry matter content (LDMC) from 13 secondary forest communities, along a 3000-m elevation transect. We derived basal area-weighted mean community (CWM) trait values to assess the effect of climate and disturbance on the functional structure of regenerating tree communities. Results: Community LFT progressively shifted along the elevation gradient driven by changes in temperature and successional stages towards communities with thicker leaves with low SLA. Reduction in LDMC with elevation suggested that both succulence and sclerophylly were important strategies in these forests. Conclusions: Our findings reinforce the validity of LFT as a powerful predictor to explore the ecological strategies of tree species in climate scenarios. Warmer conditions could result in a shift from slower to faster resource acquisition strategies at higher elevations.

Leaf development and anatomy of in vitro-grown Polygala paniculata L. are affected by light quality, gelling agents, and sucrose

Plant in vitro growth performance is influenced by environmental, physical, and chemical conditions. The present study evaluated the mutual effect of light, gelling agents, and sucrose concentration on leaf anatomical structure of in vitro-grown Polygala paniculata. Nodal segments were inoculated on agar- or Phytagel®-gelified medium supplemented with 15 g L−1 or 30 g L−1 sucrose. Cultures were grown under fluorescent lamps, light-emitting diodes (LEDs) with white light, and LEDs with blue and red light at 56 µmol m−2 s−1 photon flux. After 45 days of culture, leaf histology was assessed. The leaves of P. paniculata had an uniseriate epidermis and dorsiventral mesophyll. Gelling agents had antagonistic effects in relation to sucrose concentration. Growth on agar and 30 g L−1 sucrose induced greater leaf blade thickness, with expanded palisade and spongy parenchyma but looser intercellular spaces. In contrast, growth on Phytagel® led to significantly thicker palisade parenchyma at 15 g L−1 sucrose. Fluorescent lamp light favored in vitro leaf development of P. paniculata grown on agar; whereas spectral quality had no effect on leaf blade thickness in Phytagel®-grown plants. In summary, mutual combinations of gelling agent, light quality, and sucrose concentration influence the establishment and anatomic structure of leaves in P. paniculata plantlets grown in vitro. This result will facilitate studies on in vitro propagation of this important medicinal species.

THE INFLUENCE OF SOME CHARACTERISTICS OF THE LEAF FLAG ON THE PRODUCTION OF AUTUMN OATS

In recent years, the production and quality of autumn oats have been influenced by the evolution of climate change, characterized by high temperatures and low rainfall.This agricultural year is part of the evolution of the climate through a very warm autumn, extremely poor in rainfall, which led to a difficult preparation of the germination bed for sowing, of poor quality, and the growth of the crop began in winter and ended in next spring. Rainfall and storms in June and July caused a strong fall of plants with major consequences on the quantity and quality of production and delaying the optimal time for harvesting.The ideal production for oats is about 6 tons per hectare, but depending on climatic conditions, technologicaland quality parameters, this value can fluctuatefor autumn oats, an essential requirement is frost and winter hardness, which is also conditioned by other factors.In this study, 15 genotypes from the comparative competition culture for autumn oats were analyzed in the Oat Breeding Laboratory of S.C.D.A. Lovrin to determine the factor with the greatest influence on production in terms of chlorophyll variation,blade thickness and leaf area. Thus, the impact of the flag leaf on the production parameters was determined, by establishing the factor with the most obvious influence.The parameters studied in this experiment were leaf area, leaf blade thickness and chlorophyll content. The flag leaf was used for the indicated determinations. In each of the 15 variants, 40 standard leaves were harvested and analyzed in the laboratory, using the following devices: LI-300 Portable Area Meter (leaf surface) and SPAD 502 Chlorophyllmeter.Following the evolution of production in the analyzed period under the influence of the 3 factorsstudied, we can conclude the following: when the chlorophyll content increases by 1%, the production increases by 0.26%; when the thickness of the leaf blade increases by 1%, the production decreases on average by 0.13%; when the leaf area increases by 1%, the production decreases on average by 0.001%.

Leaf angle distribution in Johnsongrass, leaf thickness in sorghum and Johnsongrass, and association with response to Colletotrichum sublineola

Basal leaf angle distribution was surveyed in twenty-one Johnsongrass cultivars near the end of the vegetative stage. The angles increased from the top to the bottom leaves, and compared to cultivated grain sorghums, the average angle was larger in Johnsongrass. When basal leaf angle distribution data were correlated with pathogenicity test data from excised-leaf assays for three isolates of Colletotrichum sublineola, the results showed a weak positive correlation between basal leaf angle and pathogenicity level in Johnsongrass. In order to investigate a protective role of leaf thickness to C. sublineola, leaf thickness was measured in three sorghum cultivars and one Johnsongrass cultivar at the 8-leaf-stage. Leaf thickness near the apex, near the base, and half-way between the two points were measured in the top four leaves of each plant. Thickness of leaf blade and midrib were recorded separately. Using an excised-leaf-assay, the three points were inoculated with C. sublineola, and pathogenicity level was recorded 4-days-post-inoculation. Results showed strong negative correlations between leaf midrib thickness and pathogenicity level in sorghum and Johnsongrass but not in leaf blades.

A Preliminary Study on Morphological Variations from Wet and Dry Microhabitats of Hyophila involuta (Pottiaceae, Bryophyta): A Case Study from Chiang Mai Province, Northern Thailand

The morphological variations of a cosmopolitan moss, Hyophila involuta (Hook.) A. Jaeger, are reported here using t-test to distinguish 2 distinct forms of ecotypes (humid and arid forms). Three replicates each from 145 collections from 27 places in Doi Inthanon National Park, Doi Suthep-Pui National Park, and Chiang Dao Wildlife Sanctuary, Chiang Mai province, northern Thailand were examined. Eleven gametophytic characters were measured such as stem height, branching, stem diameter, leaf size, leaf blade thickness, size of median and basal laminal cells, length of innermost perichaetial leaf, and length of archegonia. Of these, 10 characters, viz. stem height, leaf size, stem diameter, branching, length of basal laminal cells, length of innermost perichaetial leaf, and length of archegonia were significantly different among populations. Other additional features of the two different ecotypes of H. involuta were recorded and discussed including leaf apices, innermost perichaetial leaf apices, marginal teeth, hyaline nodules, and number of cortical and medullary central strand cells.

Leaf Response to Different Light Spectrum Compositions during Micropropagation of Gerbera Axillary Shoots

The experiment evaluated the influence of different light qualities and 6-benzyladenine (BA) concentration in a medium on the leaf response of multiplied Gerbera jamesonii Bolus ex Hook. f.‘Big Apple’ shoots. Three different light-emitting diode (LED) spectra—100% blue (B), 100% red (R) and red and blue mixture (7:3, RB)—were used, and a fluorescent lamp was used as a control (Fl). Concentrations of BA in Murashige and Skoog (MS) medium were 1, 2.5 and 5 µM. Leaves developed under 100% blue light had a lower frequency of stomata and a smaller area as compared with those from plants exposed to light with red in spectrum. Under 100% red light, the leaf area and the frequency of stomata increased along with growing concentration of BA in the medium. The thickest mesophyll was spotted in the cross-section of leaves exposed to the blue LED light. Leaves developed under the 100% red light had the thinnest mesophyll layers. Increasing concentration of BA in the medium resulted in enhanced leaf blade thickness. The cross-section of leaf vascular bundles was only half of that in petioles. The leaves under the LED combinations had larger vascular bundles than those under fluorescent light. The highest level of photosynthetic pigments was noticed in the leaves grown under LED R and RB lights. Our study demonstrated that 2.5 µM BA and a mixture of blue and red light provided by LED improved leaf quality during multiplication of gerbera shoots.