Leaf Blade Thickness Research Articles

Effects of crude oil on plant growth and leaf anatomical structures in a common coastal plant

Phenotypic plasticity is one mechanism that allows organisms to adapt to changing environmental conditions, and is especially important for plants since they are generally immobile. Recent anthropogenic disturbances such as oil spills have expanded the types of stressors that plants must cope with, and more work is needed to understand the extent to which plants can adapt. This study examined the physiological and anatomical responses of Ipomoea pes-caprae to crude oil, and determined its plasticity in response to crude oil. Four concentrations of crude oil (1%, 2%, 3%, and 4% v/w) were applied to experimental plants and then compared with control plants over the next 120 days. Crude oil meaningfully impacted 4 out of 5 physiological characters (survival time, leaf length, leaf width, and chlorophyll content) and 4 out of 19 anatomical characters (leaf blade thickness, leaf spongy layer height, leaf adaxial cutin thickness, and leaf abaxial cutin thickness). These results demonstrate that I. pes-caprae exhibits low anatomical plasticity in response to crude oil, resulting in reduced survival and physiological performance. Our findings highlight the importance of understanding how anthropogenic actions affect relatively immobile plants, which are not always able to cope with such stressors.

EFFECT OF SEQUENTIAL CONCENTRATIONS OF ZINC AND ITS COMBINATION WITH CALCIUM OR GLUTATHIONE ON THE GROWTH, WATER RELATIONS AND ANATOMY OF ROOTS, STEMS AND LEAVES OF PHASEOLUS VULGARIS CV. CONTENDER

Zinc (Zn) is one of the eight essential micronutrients. It is needed by plants in small amounts, but yet crucial to plant development. A solution culture experiment was conducted to study the variation in growth, water relations and anatomy of roots, stems and leaves of Phaseolus vulgaris cv. contender treated with 1, 200, 400, 600, 800, 1000and 1200 mMZnSO4. Maximum significant deplete in parameters of growth (Length of root and shoot; fresh and dry weights, relative growth rate; No of leaves and leaf area), stomatal index and rate of transpiration was observed with, 200, 400, 600, 800, 1000and 1200 mM ZnSO4. These effects were improved by the addition of Ca2+than the addition of glutathione at 10 mM. Moreover, there were a significant increase at low concentration (1mM) treatment. Width of root, width of cortex and width of vascular bundles were increase with increasing Zn concentrations either alone or in combination with glutathione >Ca (NO3)2. For stem, the No of vascular bundles were decreased with increase in Zn concentration alone and with Ca (NO3)2, meanwhile increase with glutathione. Width of cortex and No of its rows were decrease with increase Zn concentrations. For leaves, the thickness of leaf blade, mid rib and vascular bundle were increase with increase the Zn concentrations alone, On other hands, they records a significant decrease in combination of Zn with Ca(NO3)2 or glutathione . In general, an increase in total uptake of zinc with increasing the concentration of Zn in all treatments. However, Ca (NO3)2 decrease these amounts than glutathione.

Stem and leaf functional traits allow successional classification in six pioneer and non-pioneer tree species in Tropical Moist Broadleaved Forests

More than half of the tropical forests are secondary forests that are undergoing a highly dynamic interplay of forest succession of uncertain outcome. Vegetation models can help predict forest trajectory but require simplifying the high biodiversity of these forests into a few distinct classes of functional or successional groups. The classification of tree species by successional groups has traditionally relied on qualitative criteria such as life span, or on parameters that are difficult to measure on mature trees in the field, like photosynthetic activity, in particular in tropical forests. Hence, quantitative traits that can be easily measured in a number of species may provide more accurate classification thresholds. The present study identifies quantitative anatomical and biochemical traits of leaf and stem of six species that are useful for classification of successional groups in the Tropical Moist Broadleaved Forest (TMBF) of south-eastern Brazil. Consistent with assumed fast growth and high light requirements of pioneers the investigated pioneer species presented higher stem glucose content (600%), larger vessel elements (162%), greater stomatal density (72%) and higher chloroplastic pigments concentrations (90%) than non-pioneer species. By contrast, non-pioneers were characterized by larger mesophyll cells (70%) and higher cell wall polymers concentrations (65–100%) in leaf and stem. The biggest differences between pioneer and non-pioneer species were observed in leaf blade thickness, followed by vessel lumen diameter, and stem lignin. We provide research laboratories a variety of different tools that they can use as a guideline to accurately assess the successional class of tree species in the TMBF of south-eastern Brazil.

The effect of pruning practice and term on a leaf area of apple-trees

The article is devoted to the study of morphological changes of the apple leaf apparatus in the intensive plantations depending on different methods and terms of pruning. The article scientifically substantiates and proves that changes in the leaf apparatus primarily depend on the timing and methods of pruning the crown. It was found out that the contour pruning of apple trees is 14% larger than the area of the leaf blade, and after pruning in the pink cone phase - 11%, the implementation of this agricultural measure in the pink cone phase increases the total leaf surface by 20%, thickens the leaf blade by 8% and reduces the number of leaves of apple trees by 17%. Key words: apple tree, pruning method, pruning period, mechanical (contour) pruning, leaf surface area, leaf blade thickness.

Leaf characterization of Spermacoce verticillata at three stages of development

Weed control is an essential practice in crop management. However, the use of herbicides may not be effective in certain situations, such as when problems are encountered in the application technology and when tolerant individuals and resistant biotypes are observed. In the cotton producing areas of the state of Bahia, Brazil, Spermacoce verticillata (shrubby false buttonweed) is not effectively controlled during burndown applications. During different developmental stages, plants can modify their leaves’ anatomical structures, which may influence herbicide control by modifying the retention, absorption, translocation and final effect of the chemical. This study assessed the morphological and histological differences in Spermacoce verticillata leaves at different stages of development. Leaves were collected from plants at different phenological stages (2-4 leaves, 4-6 leaves and flowering) and subjected to histological and scanning electron microscopy analyses. In the histological analysis, four leaves were collected from the upper nodes. The evaluated characteristics were the total leaf blade thickness, palisade and spongy parenchymal thicknesses, cuticle and epidermal cell thicknesses on the abaxial and adaxial surfaces and midrib height and width. Surface analyses were performed by observing the leaves under a scanning electron microscope. As the developmental stages of Spermacoce verticillata advanced, the plants began to show reduced leaf thickness due to the decreased abaxial epidermal thickness, transport vessel size and parenchymal thickness. At more advanced stages of development (4-6 leaves and flowering), the adaxial leaf surfaces showed fewer stomata and more trichomes.

Utilization of Volcanic Ash and Magnetite Mineral for Peanut Crop Production

A field experiment was carried out on sandy soil at Ismailia Governorate during two consecutive seasons of 2017-2018 under dripping irrigation system to study the effect of applied volcanic ash and magnetite mineral alone or mixture compared to recommended fertilizers (chemical fertilizers) as control on soil properties, peanut yield and its quality.The obtained results show that soil salinity, pH and soil bulk density were decreased in volcanic ash, magnetite mineral and volcanic ash + magnetite mineral combined treatments, as compared to the control one. The total porosity and water holding capacity (WHC) values were augmented when soil treated by volcanic ash, magnetite mineral and volcanic ash + magnetite mineral, as compared to control. In addition, Hay and pod dry weight were significantly increased with combined treatment 26.40 and 65.00 %, respectively over the control treatment. The NPK contents were augmented due to the application of volcanic ash; it also amplified zinc concentration in hay four times and in seed three times that of control treatment. Manganese concentration followed the same trend of Zn concentration. Iron concentration increased almost five and four times compared with control treatment in hay and seed. Cupper concentration increased by 30 and 70 % in comparison to control treatment in hay and peanut seed, respectively due to volcanic ash application. The highest values of net photosynthesis rate as well as water use efficiency were also obtained from volcanic ash + magnetite mineral combined treatment as compared to those under control plants. The mixture of volcanic ash with magnetite mineral realized the highest oil content and total amino acids. Anatomical studies revealed significant increase in leaf features represented in midrib thickness, length and width of vascular bundle, phloem and xylem tissues and number of xylem vessels in vascular bundle as well as the leaf blade thickness compared to control plants. Combination of volcanic ash with magnetite mineral gave the maximum net profit as compared to control treatment. The agronomic efficiency could be arranged in the following descending order of volcanic ash plus magnetite mineral, > volcanic ash, > magnetite mineral, and finally > control.

Morphological and physiological features of the miniature rose cultivar ‘Rise’n’Shine’ under long time culture in vitro and in vivo

Due to the early, long-term (over 200 days) and multiple repeated flowering, miniature roses (Rosa chinensis var. minima (Sims) Voss) are very popular in southern Russia. The morphogenetic and adaptive capacity of hardly propagated perspective cultivar ‘Rise’n’Shine’ from the collection of the Nikita Botanical Gardens cultured in vitro and in vivo was analyzed. The microshoots were regenerated on MS medium with 0.25 and 0.50 mg L-1 BAP in a growth chamber (24±1°C, 16-h photoperiod, 37.5 μmol m-2 s-1). The term of in vitro culture was 2 years. Adaptation in vivo and a subsequent cultivation of plantlets were carried out in the greenhouse for one year. Under in vitro conditions 1-3 microshoots per explant were obtained, 5.2-5.6 cm height with 9-16 ternate leaves. Leaflets’ size was 0.4×0.5 cm. Leaf blades were of bifacial type, 92±6 μm thick, covered with a single layer of epidermis and a thin cuticle. Mesophyll was differentiated and consisted of one palisade cells layer and 3-4 layers of spongy tissue. Palisade ratio was 0.47. The leaves were hypostomatic, stomatal apparatus were of anomocytic type, 270-292 stomata mm-2 of adaxial epidermis. The hydration was 86% with a bound water part – 53% of the total water content. Photosynthetic activity was 0.66-0.70 relative fluorescence units (RFU). A plant height ex vitro was 15.3-31.8 cm. Each plant had 5-7 shoots with imparipinnate leaves (with 5 leaflets). The leaflets were up to 2.5 cm long. Leaf blade thickness was 172±14 μm, the cuticle – 3-6 μm, single-layer mesophyll – 5-7. Palisade ratio was 0.58. Stomata length – 18-20 μm; 120-136 stomata mm-2. The total water content was lower than in the microshoots in vitro – 74%, and the part of bound water was 78%. Photosynthetic activity increased up to 0.82 RFU.

Ecological anatomy of Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks. (Myrtaceae) leaves in the Restinga region, state of Ceara

Abstract Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks. (Myrtaceae) species, commonly known as pitomba-da-baía, occurs in Restinga region in the state of Ceara and has medicinal potential. The present study aimed to characterize the anatomy of E. luschnathiana leaves in the rainy and dry seasons, as well as in the sun and shade in the Restinga region of Ceara, aiming to generate useful information to understand the adaptive value of morphoanatomic responses to the natural conditions of occurrence of the species. Collections were performed at the State Botanical Park of Ceara, and leaves were completely expanded and fixed in FAA70, being replaced by 70% ethanol after 24 h. Samples were submitted to standard plant anatomy methodologies in order to qualitatively and quantitatively analyze the leaf blade and petiole structures. As a result, there were differences among sun and shade leaves, rain and dry. In relation to luminosity, most determinations were higher in sun leaves: trichome density and frequency; trichome scar frequency; stomatal frequency, stomatal index, length, width and area of stomata; thickness of leaf blade, mesophyll, cuticle, epidermis, palisade and spongy parenchyma; length and width of the central vein, area of the central vein vascular bundle, number of secretory cavities in the central vein; length and width of the petiole, area of the petiole vascular bundle; amount and area of secretory cavities in the petiole. In shade leaves, only the number of druses in the central vein and petiole were larger. Regarding seasonality, all determinations were higher in the rainy season, except for the length and width of the central vein; number of druses in the central vein and petiole; length of the petiole, area of the vascular bundle and secretory cavities of the petiole. Therefore, it could be concluded that E. luschnathiana has great acclimative capacity to conditions of intense luminosity and periods of water deficit.

Effects of temperature and light intensity on morphological and phytochemical characters and antioxidant potential of wormwood (Artemisia absinthium L.)

The effect of temperature and light intensity on the growth and the production of active ingredients of Artemisia absinthium L. was studied. To this purpose, young plants of two wormwood accessions with different geographical origin were grown for 14 weeks in climatic chambers under two controlled conditions identified as "warm" and "cold", respectively. Both the tested environments (warm, with temperature from 18 °C/10 °C to 27 °C/19 °C and 16 klx light intensity, and cold, with increasing temperature from 13 °C/8 °C to 18 °C/10 °C and 8 klx light intensity) were with 14h day/10h night rhythm. The results showed that the leaf blade thickness of both accessions increased and an approximately 50% higher biomass was achieved in the “warm” chamber. Volatile compounds were accumulated in both the wormwood accessions, but some differences, mostly quantitative, in the chemical composition of their essential oils could were observed. In particular, it was found that Spanish accession was a “cis-epoxy-ocimene” chemotype, while the Hungarian accession had a variable profile with sabinene and â-myrcene as the most characteristic components. The ratio of cis-chrysanthenyl acetate grew from 8.0% (in the “cold” chamber) to 13.8% (in the “warm” chamber) in the Spanish plants, while sabinene increased from 2.3% to 10.8% and β-myrcene rose from 8.0% to 16.5% in the “warm” and “cold” chambers, respectively in the Hungarian samples. The total phenolic content (44% increase) and the FRAP antioxidant capacity (77% increase) were detected under higher temperature conditions, especially in the Spanish accession. In this respect, significant differences between the accessions appeared only in the “warm” chamber.

Colored shade nets induced changes in growth, anatomy and essential oil of Pogostemon cablin.

The purpose of this investigation was to determine the influence of colored shade nets on the growth, anatomy and essential oil content, yield and chemical composition of Pogostemon cablin. The plants were cultivated under full sunlight, black, blue and red nets. The harvesting was performed 5 months after planting and it was followed by the analysis of plant growth parameters, leaf anatomy, essential oil content, yield and chemical composition. The plants grown under red net have produced more leaf, shoot, total dry weight and leaf area. Plants cultivated under colored nets showed differences in morphological features. Plants maintained under red net had a higher leaf blade thickness and polar and equatorial diameter of the stomata ratio. Additionally, higher yield of essential oil in the leaves was observed under red and blue colored shade net. The essential oil of the plants grown under red net showed the highest relative percentage of patchoulol (66.84%). Therefore, it is possible using colored shade nets to manipulate P. cablin growth, as well as its essential oil production with several chemical compositions. The analyses of principal components allowed observing that pogostol has negative correlation with α-guaiene and α-bulnesene. There was difference in total dry weight and patchoulol content when the patchouli is cultured under the red colored shade nets.

Beating cold by being tough: impact of elevation on leaf characteristics in Phleum himalaicum Mez. endemic to Himalaya

Effect of altitude on leaf responses in Phleum himalaicum populations was evaluated at three different elevation levels, viz. (Low 1200 m.a.s.l.), middle (1600 m a.s.l.) and high (1900 m a.s.l.) in western part of Himalaya. We hypothesized that physico-chemical properties of soil varied along elevation and Phleum populations located at high elevation would adapt more distinct morphological and physiological traits than those originating from middle and low elevation sites. Our study revealed that soil pH, Ec Mg, Ca, and P decreased at high elevation however, significant increase was recorded in soil K, organic matter, and total nitrogen along the elevation gradient. A significant correlation between leaf characteristics and elevation sites was recorded along the gradient. The outcomes of this study showed that highland population had better adjustments under low temperature and exhibited adaptive traits. These were, decreased number of leaves and leaf area, increased leaf blade thickness, intensive sclerification, and greater stomatal and trichome density. Apart from these, high elevation population had more physiological adjustment in terms of low stomatal conductance, low transpiration rate, high water use efficiency, and synthesis of more osmolytes in leaf. We argued that certain level of sugar and protein must be attained by high population to dodge the aggressive climatic forces in order to grow successfully at the highest elevation. Furthermore, altitude between 1600 and 1900 m was more likely an optimum zone for vigorous growth of P. himalaicum at the highest level of elevation.

Anatomic and physiological responses of Panicum aquaticum related to cadmium tolerance

This study evaluated anatomic and physiological modifications in <i>Panicum aquaticum</i> plants related to cadmium (Cd) tolerance. The plants were cultivated in a nutritive solution, with addition of increasing concentration of Cd. The following parameters were analyzed: absorption, translocation, concentration and Cd accumulation, growth, gas exchanges, activity of the antioxidant system, and anatomy of roots and leaves. Absorption and Cd concentration increased throughout the treatments, while accumulation and Cd translocation did not vary, due to maintenance of the biomass. Gas exchanges were not affected by Cd. Specific foliar area increased in the presence of the metal, and might be related to the reduction in leaf blade thickness and chlorophyllic parenchyma. Modifications in stomatal characteristics did not negatively affect gas exchanges. An increase in the exodermis and endodermis thickness restricted Cd translocation to the aerial part, avoiding damages to the photosynthetic system. Activity of the ascorbate peroxidase and catalase in the root contributed to a reduction in the metal toxicity. <i>P. aquaticum</i> presented an efficient capacity for Cd absorption, but restricted translocation. Cd accumulation was higher in the roots. Anatomic and physiological responses show a tolerance of the species to Cd in the evaluated concentrations.

Silicon and agar on in vitro development of cockscomb (Amaranthaceae)

Abstract: The objective of this work was to evaluate the effect of silicon and agar concentrations on cockscomb (Celosia cristata) (Amaranthaceae) development in vitro. Phytotechnical, anatomical, and ultrastructural analyses were carried out in a completely randomized design, in a 4x3 factorial arrangment, with four silicic acid concentrations (0.0, 0.5, 1.0, and 1.5 g L-1) and three agar concentrations (5.5, 8.0, and 10.5 g L-1), totaling 12 treatments with seven replicates. Celosia cristata explants were inoculated in vitro in a Murashige &amp; Skoog (MS) culture medium, with 30 g L-1 sucrose. The analyses were conducted 30 days after inoculation. Phytotechnical traits improve with agar concentration of 8.0 g L-1, and the association of this concentration with 1.0 g L-1 silicon also contributes to the improvement of anatomical attributes, especially of leaf blade width and thickness of the palisade and spongy parenchyma, which contributes to the development of C. cristata. None of the evaluated combinations of agar and silicon contributes to Si deposition on the foliar epidermis of this ornamental species.

Production and leaf plasticity of rose plants sprayed with paclobutrazol and daminozide

The aim of this work was to evaluate morphological and anatomical alterations in leaves of ‘Yellow Terrazza’® and ‘Red White Terrazza’® pot roses sprayed with paclobutrazol (0, 40, 60, 80 mg L-1) and daminozide (0, 2000, 4000, 6000, 8000 mg L-1). The experiments were conducted under greenhouse conditions using a factorial treatment design (cultivars x growth retardant doses) with five replications and experimental units arranged in randomized blocks. Cv. Yellow Terrazza ® presented higher plants, greater floral diameter and leaf area than cv. Red White Terrazza ®. Plant height, leaf area, and flower diameter decreased linearly with paclobutrazol and daminozide doses. In addition, paclobutrazol and daminozide applications changed leaf tissue proportions by increasing the thickness of leaf blade, mesophyll, palisade parenchyma, and spongy parenchyma but did not influence the thickness of leaf epidermis.

Practical aspects of applying statistical analysis of quantitative characters of сutting lettuce varieties var. &lt;em&gt;сapitata&lt;/em&gt; L.

Purpose. To determine and substantiate practical aspects of statistical analysis application for management results of the morphological description of cutting lettuce (Lactuca sativa L.) varieties when identifying them during corresponding phenological phases of growth and development. Methods. Field study, analytical approach based on descriptive statistics and cluster analysis. Results. Quantitative values of display of such morphological characters as leaf rosette diameter, lettuce head size, leaf blade thickness and its venation were determined for the Lactuca sativa L. varieties. Statistical indices of four morphological characters of randomized sampling frame of seven cutting lettuce varie­ties were determined and the results of statistical analysis were interpreted. Cutting lettuce of loose leaf and capitate varieties was identified during corresponding phenological phases of growth and development. The most suitable method for clustering cutting lettuce varieties was defined. The results of clustering were interpreted. It was found that ‘Hodar’ variety differed greatly from others, ‘Dumka’ and ‘Olzhych’ varieties were the most similar. Conclusions. The results of the identification allowed to establish that capitate lettuce varieties were similar in the following combinations: ‘Bona’ and ‘Dyvohray’, ‘Olzhych’ and ‘Dumka’. According to the duration of interphase periods, it can be noted that such varieties as ‘Dumka’ and ‘Dyvohrai’ had the highest rate of maturation in comparison with ‘Bona’ and ‘Hodar’ varieties, and the lowest one as compared to the ‘Olzhych’ variety

Leaf anatomy of cassava (Manihot esculenta Crantz. cv. IAC-12) after herbicides application to control weeds in Minas Gerais, Brazil

Micro-morphological changes precede the appearance of visible damage after herbicide application and are essential in providing data for the safe recommendation in chemical management of weeds. Therefore, the aim of this research was to verify the anatomical changes of leaf tissue caused by application of herbicides in cassava (Manihot esculenta Crantz. cv. IAC-12). A greenhouse experiment was conducted with post-emergence herbicides treatments as follows: nicossulfuron (60 g a.i ha-1), fluazifop (250 g a.i ha-1), fomesafem (250 g a.i ha-1), metribuzin (480 g a.i ha-1), oxyfluorfen (720 g a.i ha-1) and the mixture fluazifop + fomesafen (200 + 250 g a.i ha-1), and an untreated control, respectively. The results obtained have allowed to affirm the cassava plants (cultivar IAC-12), exhibited changes in leaf anatomy in response to herbicide application even on cassava leaves without no visual toxicity symptoms. The products caused alterations both in tissue thickness as in tissue proportion in the leaf blade. For the fluazifop, a eudicotyledonous selective herbicide, changes were observed in tissue thickness and proportion of leaf blade, even without any visual toxicity detected. Cassava plants (IAC-12), showed structural changes in leaf anatomy in response to application of herbicides. The leaf anatomy of cassava cv. IAC-12, can be used to indicate the herbicide effect on cassava (Manihot esculenta Crantz.cv. IAC-12) plants.

Salt stress and exogenous silicon influence physiological and anatomical features of in vitro-grown cape gooseberry

ABSTRACT: Salt stress is one of several major abiotic stresses that affect plant growth and development, and there are many evidences that silicon can ameliorate the injuries caused by high salinity. This study presents the results of an assay concerning: (1) the effect of in vitro NaCl-induced salt stress in cape gooseberry plants and (2) the possible mitigating effect of silicon in saline conditions. For that, nodal segments were inoculated in Murashige and Skoog (MS) medium under salinity (0.5 and 1.0% NaCl) with different silicic acid concentrations (0, 0.5 and 1.0g L-1). Phytotechnical characteristics, photosynthetic pigments content, and leaf anatomy were evaluated after 30 days. Shoot length, root length, number of leaves and buds, fresh and dry weight, pigment content, stomatal density and leaf blade thickness were drastically reduced by increased salt level. The supply of silicon (1.0g L-1) has successfully mitigated the effect of salinity at 0.5% NaCl for chlorophyll, carotenoids, stomatal density and leaf blade thickness. When salt stress was about 1.0%, Si was not effective anymore. In conclusion, we affirmed that, in in vitro conditions, salt stress is harmful for cape gooseberry plants and the addition of silicon showed effective in mitigating the saline effects of some features.

Shading and natural rooting biostimulator enhance potential for vegetative propagation of dogwood plants (Cornus alba L.) via stem cuttings

Auxins have been widely used to stimulate rhizogenesis in stem woody cuttings. Recently, more environmentally friendly biostimulators are reported to enhance rhizogenesis. Also, stock plants shading appears to be an easy and effective method to increase rooting of cuttings. The aim of the study was to examine the effect of shading and exogenous application of auxin or biostimulator AlgaminoPlant on rooting potential of two cultivars of dogwood (Cornus alba L.) and to detect anatomical modifications induced by shading that may be related to rooting ability. Stock plants were shaded with a nursery net reducing 50% of light for 6weeks prior to cuttings' harvest while the control stock plants were grown under ambient light. Cuttings from shaded and non-shaded plants were treated with a commercial rooting powder (1% IBA), sprayed with water solution of IBA (200mg·l−1) or with biostimulator AlgaminoPlant (0.2% v/v), whereas the control cuttings were sprayed with water. The effects of treatments were evaluated after 8weeks of rooting in a plastic tunnel. The two cultivars tested differed in natural as well as induced rooting potential, both in cuttings harvested from shaded stock plants and those grown under ambient light. Shading of stock plants significantly improved rooting abilities in comparison to control cuttings from plants grown under ambient light. Shading reduced diameters of stem and pith, with thinner layers of cortex, epidermis and collenchyma; vascular bundles and diameters of xylem vessels were also smaller. The thickness of leaf blades collected from shaded stock plants was lower due to thinner epidermal as well as spongy and palisade mesophyll layers. The best effects in rooting were obtained when shading was followed by the application of rooting inducers. The effects of synthetic auxin IBA and biostimulator AlgaminoPlant were similar; therefore, the latter is a viable option to reduce widespread use of rooting inducing chemicals based on synthetic auxins.

In vitro conservation and leaf anatomy of different chemotypes of Lippia alba (Mill.) N. E. BR

The aim of this work was to develop an in vitro conservation protocol for Lippia alba that involved mineral oil and to study the leaf anatomy of L. alba genotypes in in vitro and ex vitro environments. In vitro conservation involved five genotypes; LA-13 and LA-57 (carvone chemotype); LA-22 (linalool chemotype); and LA-29 and LA-44 (citral chemotype). Each genotype was treated with mineral oil, with water, and a control at 18°C and 23°C. Survival (%), shoot height (cm) and leaf color were assessed at 180 and 270 days. The genotypes with the best in vitro conservation outcomes (LA-13 and LA-57) were used to study the anatomy of the leaves. Midrib thickness, leaf blade thickness, adaxial and abaxial cuticles and the number of glandular and tector trichomes were assessed. A temperature of 18°C was optimal for the conservation of genotypes of the carvone chemotypes. The explants were short and had green leaves. This was especially true for LA-57, whose height did not exceed 2.0 cm. At 270 days, the LA-13 and LA-57 genotypes continued to have green and viable leaves, especially LA-57, which had the lowest mean height. Field plants of the carvone chemotype had thicker midribs, leaf blades, and cuticles and had more trichomes. The LA-57 genotype had the most glandular and tector trichomes.

Structural changes in leaves and roots are anatomical markers of aluminum sensitivity in sunflower1

ABSTRACT Aluminum (Al) toxicity in plants evidences the importance of genotype evaluation to the identification of tolerance markers. This study aimed at evaluating the effects of aluminum stress on the relative water content, membrane damages and anatomical changes, in Al-tolerant and Al-sensitive sunflower cultivars. Sunflower plants [Catissol (Al-tolerant) and IAC-Uruguai (Al-sensitive)] were grown in nutrient solution (control) or nutrient solution containing 0.15 mM of AlCl3 (Al-stress treatment), in a greenhouse. The experimental design was completely randomized, in a factorial arrangement consisting of four harvest times x two sunflower cultivars x two Al levels, with four replications. The results showed that Al negatively affected the absolute integrity percentage and relative water content only for the IAC-Uruguay cultivar. These results in the stressed leaves of the Al-sensitive cultivar may be due to damage in the xylem structure. In addition, the increase in leaf blade thickness and parenchyma layers, as well as lignification of root tissues, are important traits of IAC-Uruguay plants and may be used as anatomical markers of Al sensitivity in sunflower.