Effects of different LEDs light spectrum on the growth,leaf anatomy,and chloroplast ultrastructure of potato plantlets in vitro and minituber production after transplanting in the greenhouse

Light spectrum plays an important role in regulating the growth and development of in vitro cultured potato(Solanum tuberosum L.) plantlets. The status of potato plantlets at the end of in vitro stage influences the minituber production after transplanting. With 100 μmol m^-2s^-1 total photosynthetic photon flux density(PPFD), a light spectrum study of 100% red light emitting diodes(LEDs) light spectrum(RR), 100% blue LEDs light spectrum(BB), 65% red+35% blue LEDs light spectrum(RB), and 45% red+35% blue+20% green LEDs light spectrum(RBG) providing illumination at the in vitro cultured stage of potato plantlets for 4 weeks using fluorescent lamp as control(CK) was performed to investigate the effects of LEDs light spectrum on the growth, leaf anatomy, and chloroplast ultrastructure of potato plantlets in vitro as well as the minituber yield after 2 months transplanting in the greenhouse. Compared to CK, RB and RBG promoted the growth of potato plantlets in vitro with increased stem diameter, plantlet fresh weight, plantlet dry weight, and health index. Furthermore, BB induced the greatest stem diameter as well as the highest health index in potato plantlets in vitro. Root activity, soluble protein, and free amino acid were also significantly enhanced by BB, whereas carbohydrates were improved by RR. In addition, thickness of leaf, palisade parenchyma and spongy parenchyma was significantly increased by BB and RBG. Chloroplasts under BB and RBG showed well-developed grana thylakoid and stroma thylakoid. Unexpectedly, distinct upper epidermis with greatest thickness was induced and palisade parenchyma and spongy parenchyma were arranged neatly in RR. After transplanting in the greenhouse for 2 months, potato plantlets in vitro from BB, RB, and RBG produced high percentage of large size tuber. BB improved fresh and dry weights of the biggest tuber but decreased tuber number per plantlet. In addition, RBG increased tuber number as well as tuber fresh and dry weight slightly. Our results suggested monochromatic blue LEDs as well as combined red, blue or/and green LEDs light spectrum were superior to fluorescent lamp spectrum in micro-propagation of potato plantlets. Therefore, the application of RBG was suitable;BB and RB could be used as alternatives.

Yield photosynthesis and leaf anatomy of maize in inter-and mono-cropping systems at varying plant densities

Increasing plant density can increase cereal crop yields. However, the physiological and anatomical mechanisms of grain yield increase at high plant densities in maize-based intercropping systems are not well understood. A two-year field experiment was conducted in 2018 and 2019 to investigate grain yield, photosynthetic characteristics, stomatal traits, and leaf anatomy of maize plants in an intercropping system with high plant densities. Two cropping patterns(monocropping and intercropping) and three plant densities(D1, 78,000 plants ha^(-1);D2, 103,500 plants ha^(-1);D3, 129,000 plants ha;were arranged in a randomized block design. Increasing maize plant density significantly increased maize yield, and intercropping gave a significant yield advantage over monocropping under the same plant density. Intercropping combined with high plant density increased the leaf area and SPAD value of maize,increasing the photosynthesis rates after the harvest of pea. At the twelfth leaf stage, the stomatal density and stomatal area of intercrops combined with medium plant density increased by respectively 10.5%and 18.4% relative to their values for the corresponding density of monocrops. Although leaf thickness of maize was reduced by increasing plant density, the chloroplast number and grana lamella number were higher in intercropping than in monocropping under different plant densities. These positive changes in leaf anatomy resulted in increased photosynthesis, suggesting a physiological basis for the increase in grain yield.

Comparative analyses of leaf anatomy of dicotyledonous species in Tibetan and Inner Mongolian grasslands

Knowledge of the leaf anatomy of grassland plants is crucial for understanding how these plants adapt to the environment. Tibetan alpine grasslands and Inner Mongolian temperate grasslands are two major grassland types in northern China. Tibetan alpine grasslands occur in high-altitude regions where the low temperatures limit plant growth. Inner Mongolian temperate grasslands are found in arid regions where moisture is the limiting factor. Few comparative studies concerning the leaf anatomy of grassland plants of the Tibetan Plateau and Inner Mongolian Plateau have been conducted. We examined leaf characteristics at 71 sites and among 65 species, across the alpine grasslands of the Tibetan Plateau and the temperate grasslands of the Inner Mongolian Plateau. We compared the leaf structures of plants with different life forms and taxonomies, and their adaptation to arid or cold environments. We explored relationships among leaf features and the effects of climatic factors (i.e., growing season temperature and precipitation) on leaf characteristics. Our results showed that (i) there were significant differences in leaf anatomy between Tibetan alpine and Inner Mongolian temperate grasslands. Except for mesophyll cell density, the values obtained for thickness of leaf tissue, surface area and volume of mesophyll cells were larger on the Tibetan Plateau than on the Inner Mongolian Plateau. (ii) Within the same family or genus, leaf anatomy showed significant differences between two regions, and trends were consistent with those of whole species. (iii) Leaf anatomy of woody and herbaceous plants also showed significant differences between the regions. Except for mesophyll cell density, the values obtained for the thickness of leaf tissue, and the surface area and volume of mesophyll cells were larger in herbaceous than in woody plants. (iv) Leaf anatomical traits changed accordingly. Total leaf thickness, thicknesses of lower and upper epidermal cells, and surface area and volume of mesophyll cells were positively correlated, while mesophyll cell density was negatively associated with those traits. (v) Growing season temperature had stronger effects on leaf anatomy than growing season precipitation. Although the communities in Tibetan and Inner Mongolian grasslands were similar in appearance, leaf anatomy differed; this was probably due to the combined effects of evolutionary adaptation of plants to environment and environmental stress induced by climatic factors.

Leaf physiological and anatomical responses of two sympatric Paphiopedilum species to temperature

Paphiopedilum dianthum and P.micranthum are two endangered orchid species,with high ornamental and conservation values.They are sympatric species,but their leaf anatomical traits and flowering period have significant differences.However,it is unclear whether the differences in leaf structure of the two species will affect their adaptabilities to temperature.Here,we investigated the leaf photosynthetic,anatomical,and flowering traits of these two species at three sites with different temperatures(Kunming,16.7±0.2°C;Puer,17.7±0.2°C;Menglun,23.3±0.2°C)in southwest China.Compared with those at Puer and Kunming,the values of light-saturated photosynthetic rate(Pmax).stomatai conductance(gs),leaf thickness(LT),and stomatai density(SD)in both species were lower at Menglun.The values of Pmax,gs,仃,adaxial cuticle thickness(CTad)and SD in P.dianthum were higher than those of P.micranthum at the three sites.Compared with P.dianthum,there were no flowering plants of P.micranthum at Menglun.These results indicated that both species were less resistance to high temperature,and P.dianthum had a stronger adaptability to high-temperature than P.micranthum.Our findings can provide valuable information for the conservation and cultivation of Paphiopedilum species.

Systematic Importance of Leaf Anatomical Characters in Some Species of Microcos Linn. Section Eumicrocos Burret. in Nigeria

The leaf anatomy of six Microcos L. species belonging to section Eumicrocos in Nigeria was investigated by transverse sectioning of the lamina and examined by light microscope to determine their taxonomic significance in species delimitation and classification. The common anatomical characteristics in all the species are as follows: the uniseriate epidermis;the hypostomatic and bifacial leaves;presence of 2 layers of palisade tissues;presence of bundle sheath extension to both epidermises;presence of glandular and non-glandular trichomes;presence of secretory ducts on abaxial surface;presence of druse crystal in the mesophyll and midrib and;sclerenchyma cells associated with the phloem. Anatomical characters which are significant for species delimitation include: the presence/absence of sclerenchyma cells associated with the xylem in the midrib;presence/absence of starch grains in the mesophyll and midrib;the presence/absence of secretory ducts on the adaxial surface of the midrib;the presence/absence of medullary plates in midrib;the number of secretory ducts in the midrib and the midrib adaxial outline. The section can be separated into two distinct groups based on the number of spongy tissue layers in the mesophyll, number of sclerenchyma cells associated with the phloem and presence/absence of sclerenchyma cells in xylem both groupings correlated with those obtained from foliar epidermal and pollen characters. The importance of these characters is discussed in relation to the taxonomy of the taxon.

Anatomical and Molecular Identification of Ornamental Plant Ficus L.Species

This present study includes twelve species that represent the Ficus genus,namely;aspera,carica,tinctoria subsp.gibbosa,hirta,hispida,neriifolia,palmata,pumila,racemosa,septica,sur,and sycomorus,belonging to the Moraceae family.The species samples were collected from various locations in Egypt.The study focused on the anatomical and molecular characteristics of mature foliage leaves.Since the identification and classification of taxa are highly dependent on the anatomical features of leaves,the anatomical characteristics were recorded in the form of a comparison between the examined plants in the data matrix.This study aims to contribute to the identification of the studied species based on the anatomical details of the matured leaves.Anatomical characterization includes the variations in upper and lower epidermal layers that are covered by a thin or thick cuticle;the number of palisade and spongy layers;crystals;secretory elements;lithocysts;the midrib zone has parenchyma associated with mechanical tissue,vascular system,and investigation of trichomes;on the other hand,in the current study,the phylogenetic analysis was conducted by using the ITS and 5.8 S sequences.From the analysis of all the available data,it could be stated that there is an overall agreement with the anatomical character dendrogram.

Study on Adaptability of Datura stramonium and Datura stramonium var. tatual to Temperature

This study was conducted to investigate the temperature adaptability of Datura stramonium and D. stramonium var. tatual. Under 4 temperature levels,plantgrowth and pigment concentrations in leaves and stems were determined, and leaf anatomic structures of D. stramonium var. tatual and D. stramonium were analyzed. The results showed that the palisade tissue thickness/sponge tissue thickness,stomatal density and stomatal index values of D. stramonium var. tatual were significantly greater than D. stramonium; the chlorophyll content/carotenoid content in leaves of D. stramonium var. tatual increased at first and decreased then, while no regularity was found in leaves of D. stramonium; and the contents of anthocyanin,flavonoids, and total phenols in stems of D. stramonium var. tatual were significantly higher than those in stems of D. stramonium. The temperature adaptability of D.stramonium var. tatual is stronger than that of D. stramonium.

Mesophyll thickness and sclerophylly among Calotropis procera morphotypes reveal water-saved adaptation to environments

Calotropis procera(Aiton)Dryand(Apocynaceae)is a native species in tropical and subtropical Africa and Asia.However,due to its fast growing and drought-tolerant,it has become an invasive species when it was introduced into Central and South America,as well as the Caribbean Islands.Currently,C.procera displays a wide distribution in the world.Invasiveness is important,in particular,because many invasive species exert a high reproductive pressure on the invaded communities or are highly productive in their new distributed areas.It has been suggested that a very deep root system and a high capacity to reduce stomatal conductance during water shortage could allow this species to maintain the water status required for a normal function.However,the true mechanism behind the successful distribution of C.procera across wet and dry environments is still unknown.C.procera leaves were collected from 12 natural populations in Brazil,Colombia and Mexico,ranging from wet to dry environments during 2014–2015.Many traits of morphology and anatomy from these distinct morphotypes were evaluated.We found that C.procera leaves had a considerable capacity to adjust their morphological,anatomical and physiological traits to different environments.The magnitude of acclimation responses,i.e.,plasticity,had been hypothesized to reflect the specialized adaptation of plant species to a particular environment.However,allometric models for leaf area(LA)estimation cannot be grouped as a single model.Leaves are narrower and thicker with low amounts of air spaces inside the leaf parenchyma in wet environments,while they are broader and thinner with a small number of palisade cell layers in dry environments.Based on these,we argue that broader and thinner leaves of C.procera dissipate incident energy at the expense of a higher rate of transpiration to survive in environments in which water is the most limiting factor and to compete in favorable wet environments.

Responses of the Host Plant Tissues to Gall Induction in Aspidosperma spruceanum Müell.Arg.(Apocynaceae)

The ontogenetic characterization of the leaf galls induced in the internervural region and in the second and third order veins of A. spruceanum Müell Arg. (Apocynaceae) aims to evaluate the distinct levels of cell reaction during the process of gall formation, and the relation between external gall morphology and the oviposition sites. The ground system had the most remarkable alterations, namely, the non differentiation of palisade parenchyma in both leaf sides, the hyperplasia of the spongy parenchyma and the neoformation of fibersclereids, a cell type not observed in non galled leaves. Changes of the feeding sites inside the larval chamber reveal distinct levels of cell competence to respond to the insects stimuli and explain the variations in the shape of the larval chamber.

Shade and sapling size influence restoration of Araucaria angustifolia

Toward improving reforestation of Brazilian pine(Araucaria angustifolia),two contrasting sapling sizes in either full sun or in the shade of a mixed plantation and the effect of opening the canopy were evaluated for survival,growth,gas exchange,photosynthetic pigments,and leaf anatomy 18 months after being planted.At 23 months after planting,a partial opening was made in the canopy in the mixed plantation,then the saplings were evaluated again after 2 months for the same morphophysiological traits.After 18 months,saplings planted in the full sun had higher survival,growth,pigments,and photosynthesis compared to the shaded saplings.Large saplings had higher survival and growth compared to the small ones.Shaded leaves were thinner and little differentiation of palisade parenchyma and hypodermis.After opening of the canopy,photo synthetically active radiation was 10 times higher,and the saplings quickly grew in height due to increased photosynthesis.Thus,although the species can tolerate shade,growth in the shade is limited.We recommend that for reforestation purposes of Brazilian pine,large saplings should be selected and planted in the open for better development.

The anatomical structure of woody plants in arid habitats is closely related to nonstructural carbohydrates storage

Background:The high temperatures and drought conditions associated with global climate change have led to the widespread death of trees and forests,which has generated research interest in the impact of non-structural carbohydrates(NSC)reserves on woody plant survival in changing environments.The anatomical characteristics of plants can affect the scale and variability of NSC reserves,and linking the anatomical characteristics of trees to NSC concentration can help answer questions about the potential role of NSC in the repair of xylem embolism during drought.Results:The anatomical characteristics,NSC concentrations and gas exchange parameters were determined in 16 common afforestation tree species in typical arid limestone habitats in rocky mountain regions.We found that the anatomical structures varied greatly among the tree species studied,and a branch xylem hydraulic efficiency-safety tradeoff was not observed.NSC concentration was significantly and positively correlated with variables including mean vessel diameter(MVD),maximum vessel diameter(XVD),potential hydraulic conductivity(Kp),vessel wall thickness(VWT),ratio of palisade tissue thickness to sponge tissue thickness(PT/ST),net photosynthetic rate(Pn),water use efficiency(WUE)and axial parenchyma cell area,and negatively with sponge tissue thickness(ST)and lower epidermis thickness(LET)of leaves.Among the four latent variables,mechanical strength was inversely related to NSC concentration,whilst hydraulic efficiency,leaf carbon fixation,and the embolism repair and storage capacity all had a positive effect.Conclusions:Our study revealed that tree species with larger vessel diameters,thicker vessel walls,more abundant axial parenchyma,and higher PT/ST have higher NSC storage in arid habitats in northern China.Varying xylem anatomical characteristics and leaf anatomical characteristics among different tree species lead to differentiated water transport and photosynthetic processes,thereby regulating the NSC concentrations.A higher NSC concentration may enhance the embolism repair capacity of plants and play an important role in maintaining hydraulic integrity in arid habitats.

Comparative Leaves Anatomical Studies of Bouea, Mangifera and Spondias （Anacardiaceae） in Malaysia

Leaves anatomy of two species of Bouea, 11 species of Mangifera and two species of Spondias were studied in order to see the differences in stomata type, petiole, midrib and lamina anatomy and leaf venation. This study aims to use anatomical characters for species and genus identification. Common characters observed were the absence of trichomes, closed vascular bundles, uniseriate epidermal layers, resin canal in parenchyma cells, anticline wall pattems and druses crystals in leaf lamina transverse sections. All species displayed closed vascular bundles except Mangiferapajang which showed a combination of medullary vascular bundles. Uniseriate epidermal layer was observed in all species. All the species showed straight-wavy anticlinal walls. Druses crystals were found in the parenchyma cells of all the species. Four types of stomata were observed namely anomocytic, anisocytic, staurocytic and diacytic. Anomocytic, anisocytic and staurocytic stomata were observed in Mangifera, diacytic in Bouea and anomocytic in Spondias.

Marigold(Tagetes erecta): The Potential Value in the Phytoremediation of Chromium

Environmental pollution with chromium （Cr） is harmful to humans, animals and plants, while in plants it causes diminished growth, anatomical alterations and death. In the present study, the potential value of marigold （Tagetes erecta） in the phytoremediation of Cr has been investigated. The randomized experimental design involved the exposure of plants to nutrient solutions containing 0.00, 0.04, 0.08, 0.12, 0.16 or 0.24 mmol L-1 Cr（III）. Chromium toxicity was observed at Cr（III） concentrations ≥ 0.12 mmol L-1 as demonstrated by diminished growth of the aerial parts and reduced density of the root system. Increasing Cr（III） concentrations in the nutrient solution resulted in a higher bioaccumulation of total Cr in the tissues, although translocation from roots to aerial parts was not efficient （maximum value of 25% at 0.12 mmol L-1 Cr（III））. The Cr bioaccumulation was up to 11-fold greater in roots than in the aerial parts. Tagetes erecta exhibited leaf plasticity when exposed to Cr, indicating the existence of a tolerance mechanism to Cr in this species. Chromium caused a reduction in xilem vases, resulting in a plastic effect in T. erecta leaves that increased the metal tolerance in culture solution. Tagetes spp. are potential Cr hyperaccumulators; at Cr（III） concentrations up to 0.12 mmol L-1, the plants accumulated levels above that proposed for hyperaccumulators and still maintained a considerable growth and even flourished. However, this study was conducted in nutrient solution, and studies on species confirmation as Cr hyperaccumulator should be conducted in soils for further clarification.