Apple Autotetraploids—Phenotypic Characterisation and Response to Drought Stress

Polyploidization is an important source of variability for plant breeding. Polyploids are often characterised by increased resistance to biotic and abiotic stresses. Since drought and pathogen attack are the main threats to apple cultivation, obtaining new sources of resistance is an important issue for apple breeding. The newly obtained autotetraploid clones of apple cv. ‘Redchief’ showed superior resistance to fire blight. The aim of the presented research was the in-depth phenotypic characterisation of ‘Redchief’ tetraploids and assessment of their response to drought at the physiological and genetic level. The growth of own-rooted five-year-old trees of ‘Redchief’ tetraploids was poor compared with diploids; all growth parameters—the number and length of current season shoots, the total length of current season shoots per tree and the cross-section area of the trunk—were reduced in tetraploid clones. Grafting on M9 rootstock improved the growth characteristics of ‘Redchief’ tetraploids. Compared with diploid plants, the leaves of tetraploids were thicker, with altered shape, higher chlorophyll content, and larger stomata, but the stomatal density decreased. The leaf anatomical structure of tetraploids was changed, the adaxial and abaxial epidermis and both types of mesophyll were significantly thicker than in diploids. Moreover, the pollen grains of tetraploids were larger, but their viability and germination were reduced. Under conditions of limited water supply, the reduction in growth parameters was smaller and the physiological parameters were higher in the ‘Redchief’ tetraploid clone 4x-25 than in diploid plants. The expression of APX gene was higher in tetraploids than in diploids 15 days after drought stress induction. The results suggest the enhanced drought tolerance of the studied ‘Redchief’ autotetraploid clone compared with its diploid counterpart.

Leaf epidermal micromorphology in Aspidistra (Asparagaceae): diversity and taxonomic significance

Micromorphological characters of leaf epidermis were investigated in 69 species of Aspidistra using scanning electron microscopy. Sculpture of epidermis varies from smooth to verrucose and rugose in the genus. The abaxial epidermis of some species bears papillae, whereas the adaxial surface uniformly lacks the papillae. Sculpture type of epidermis and density of papillae are generally found to be stable characters at a species level. The infraspecific variation of epidermis sculpture, where present, ranges from smooth to verrucose or from verrucose to rugose. Micromorphological characters of leaf epidermis are shown to have potential taxonomic significance in Aspidistra; in combination with the type of shoot structure, they allow to subdivide the species into 13 groups. The groups are largely incongruent with floral morphological traits. An identification key to the studied species of Aspidistra based on vegetative characters (gross leaf and shoot morphology and characters of leaf epidermis) is presented.

Morphological Characterization and Transcriptional Regulation of Corolla Closure in Ipomoea purpurea

Corolla closure protects pollen from high-temperature stress during pollen germination and fertilization in the ornamental plant morning glory (Ipomoea purpurea). However, the morphological nature of this process and the molecular events underpinning it remain largely unclear. Here, we examined the cellular and gene expression changes that occur during corolla closure in the I. purpurea. We divided the corolla closure process into eight stages (S0–S7) based on corolla morphology. During flower opening, bulliform cells appear papillate, with pigments in the adaxial epidermis of the corolla. These cells have distinct morphology from the smaller, flat cells in the abaxial epidermis in the corolla limb and intermediate of the corolla. During corolla closure, the bulliform cells of the adaxial epidermis severely collapse compared to cells on the abaxial side. Analysis of transparent tissue and cross sections revealed that acuminate veins in the corolla are composed of spiral vessels that begin to curve during corolla closure. When the acuminate veins were compromised, the corolla failed to close normally. We performed transcriptome analysis to obtain a time-course profile of gene expression during the process from the open corolla stage (S0) to semi-closure (S3). Genes that were upregulated from S0 to S1 were enriched in the polysaccharide degradation pathway, which positively regulates cell wall reorganization. Senescence-related transcription factor genes were expressed beginning at S1, leading to the activation of downstream autophagy-related genes at S2. Genes associated with peroxisomes and ubiquitin-mediated proteolysis were upregulated at S3 to enhance reactive oxygen species scavenging and protein degradation. Therefore, bulliform cells and acuminate veins play essential roles in corolla closure. Our findings provide a global understanding of the gene regulatory processes that occur during corolla closure in I. purpurea.

Microscopical Characterization and Physicochemical Standardization of Leaves, Stems and Roots of Spondias mombin L. (Anacardiaceae)

Background: Spondias mombin L. belongs to the family Anacardiaceae. Despite its wide ethnomedicinal applications in the management of diverse diseases, there is a paucity of documented reports on its standardization.Objectives: The present study evaluated microscopical characters and some physicochemical properties of different parts of the plant for its identification and standardization.Material and Methods: Epidermal tissue preparation of the leaf of Spondias mombin (SM) was obtained using physical method while thin sections (10-12 μm) of the stem bark and root were obtained using a rotary microtome. Physicochemical parameters were determined for the powdered samples of SM using standard methods.Results: Diagnostic characters from the epidermal tissue of the leaf revealed anomocytic, paracytic stomatal type, non-glandular trichome, smooth to slightly wavy anticlinal walls while sections of the stem bark and root were characterized with abundant sclereids and calcium oxalate crystals. The stomatal number and stomatal index of the abaxial epidermis were 23.70±0.86 and 24.62±0.78 %, respectively. Ethanol had the highest extractive value (17.84±0.50) % in the leaf whereas it was lowest in petroleum ether (1.92±0.08) %. The leaf had the lowest ash value (7.13±0.76) %.Conclusion: The microscopical characterization and some of the physicochemical parameters reported herein could be useful in the compilation of monograph for the correct identification of Spondias mombin, thus contributing to the knowledge of its collection and preservation.

Organization of leaf vascular system and gas exchange in seedlings of Guazuma ulmifolia Lam. in different light conditions

In tropical forests, different physiological characteristics of leaves in tree species are evidenced by variations in different incident light conditions. We aim to evaluate gas exchange and organization of leaf vascular system in Guazuma ulmifolia Lam. seedlings under different light conditions. Seedlings were obtained from seeds germinated under greenhouse conditions with controlled environment. Ninety days after germination, seedlings in 8kg pots were transferred to the experimental site to allow acclimatization under sun and shade conditions. The experimental design was completely randomized, with two treatments: full sunlight and artificial shading, limiting the luminosity to about 5% of irradiance. Seedlings were maintained under these conditions for 120 days before measuring gas exchange parameters. We measured photosynthetic rate, stomatal conductance, sub-stomatic CO2 concentration, transpiration, and chlorophyll content. Anatomical analysis measured distance between veins, distance from veins to abaxial epidermis, distance from veins to adaxial epidermis, distance from veins to stomata, total leaf thickness, abaxial epidermis thickness, adaxial epidermis thickness, palisade parenchyma thickness, and spongy parenchyma thickness of foliar gas exchange of G. ulmifolia which presented significant differences between light environments. Photosynthetic rate and stomatal conductance were reduced by 78% and 39%, respectively, in shade, while stomatal conductance increased by 31% in full sunlight. Transpiration showed no significant difference between the two treatments, but chlorophyll content was 30% lower in full sunlight. Distance between veins and distance from veins to stomata showed no difference between treatments, but the other parameters increased in full sunlight. Thus, the results showed that the pioneer species G. ulmifolia presented leaf gas exchange acclimated to environments with high luminosity.

Floral Longevity of Paphiopedilum and Cypripedium Is Associated With Floral Morphology

Floral longevity (FL) is an important trait influencing plant reproductive success by affecting the chance of insect pollination. However, it is still unclear which factors affect FL, and whether FL is evolutionarily associated with structural traits. Since construction costs and water loss by transpiration play a role in leaf longevity, we speculated that floral structures may affect the maintenance and loss of water in flowers and, therefore, FL. Here, we investigated the slipper orchid Paphiopedilum and Cypripedium, which are closely related, but strongly differ in their FL. To understand the evolutionary association of floral anatomical traits with FL, we used a phylogenetic independent comparative method to examine the relationships between 30 floral anatomical traits and FL in 18 species of Paphiopedilum and Cypripedium. Compared with Paphiopedilum species, Cypripedium species have lower values for floral traits related to drought tolerance and water retention capacity. Long FL was basically accompanied by the thicker epidermal and endodermal tissues of the floral stem, the thicker adaxial and abaxial epidermis of the flower, and low floral vein and stomatal densities. Vein density of the dorsal sepals and synsepals was negatively correlated with stomatal density. Our results supported the hypothesis that there was a correlation between FL and floral anatomical traits in slipper orchids. The ability to retain water in the flowers was associated with FL. These findings provide a new insight into the evolutionary association of floral traits with transpirational water loss for orchids under natural selection.

MORPHOPHYSIOLOGICAL CHARACTERISTICS OF ARABIC COFFEE

The understanding of the behavior of each cultivar under adverse climatic conditions is important in the choice of plants that best fit the region to be inserted. Due to the large number of cultivars available on the market it makes it difficult for producers to choose which material to plant. In view of the above, this study aimed to know the morphophysiological characteristics of coffee. The experimental design was in randomized blocks with 10 treatments, that is, arabic coffee varieties: Catuai IAC62; Catuai IAC99; Ouro IAC4397; Tupi RN IAC1669-13; Obatã IAC1669-20; Mundo Novo IAC379-24; Mundo Novo IAC 388-17-2; Mundo Novo SH3 Faz São José; Bourbon IACJ15 and Icatu IAC 2944-11 and with four replications totaling 40 plots, where each plot was composed of seven plants. The Mundo Novo IAC 388-17-2 coffee variety shows higher yield in the seventh year of cultivation. Variety of Bourbon IACJ15 coffee presented water use efficiency (EUW) which did not reflect in higher productivity. The Catuai V IAC99 arabica coffee variety stood out in the internal morphology of the leaves. The thickness of the adaxial and abaxial epidermis (TADE and TABE) and the CO2 assimilation rate (A) showed negative correlations with the productivity of processed coffee bags. Keywords: Coffea arabica; plant morphology; plant physiology; varieties.

Morpho-anatomical adaptation of the leaves of certain Veronica species to arid conditions

This study’s objective was to evaluate the adaptive potential of the leaves of Veronica (V. austriaca, V. incana, and V. prostrata) in the arid conditions of the Kryvyi Rih Botanical Garden NAS of Ukraine (KBG) located in the Right-Bank Steppe Cisdnieper. Leaves have been obtained from the collection of ornamental plants of KBG, where these plants are introduced for ten years. The seasonal dynamics of leaf development have been studied during the growing season of 2018, when the most arid climatic conditions were observed.The leaves of the investigated species were found to be dorsoventral, amphistomatic, with an anomocytic stomatal apparatus and bifacial mesophyll. Changes in the anatomical structures of the leaf blade towards xeromorphism were determined. In particular, in all studied specimens thickening of the cuticle, adaxial and abaxial epidermises (except V. prostrata, where the upper epidermis decreased by 35 %) mesophyll occurred. The number of stomata on the abaxial epidermis in all species decreased (the most notably in V. prostrata). Such increase of xeromorphism in V. austriaca, V. incana, and V. prostrata is an adaptive reaction of plants to the effects of extreme arid weather and climatic conditions of the Kryvorizhzhya, which testifies to the plasticity of investigated species and their high adaptation potential to the climatic conditions of the Right-Bank Steppe Cisdnieper.

Variasi Karakter Anatomis Talus Padina australis Hauck 1887 (Dictyotales, Phaeophycota) di Pantai Karang Tengah Kabupaten Cilacap

ABSTRAK: Karakter anatomi dapat digunakan untuk menentukan produktivitas kandungan alginat rumput laut P. australis Hauck. Penelitian ini bertujuan mengetahui variasi karakter anatomis talus Padina australis Hauck. Pengambilan sampel dengan purposive random sampling di pantai Karang Tengah, Kabupaten Cilacap. Persiapan mikroskopis dengan metode parafin dengan safranin 1% dalam alkohol 70%. Parameter yang diamati meliputi ketebalan epidermis, ukuran sel medula, ketebalan talus, dan ukuran tetra sporangia. Pengamatan struktur anatomi secara deskriptif dengan membandingkan karakter anatomi P. australis Hauck pada garis konsentris. Data karakter anatomi dianalisis dengan Uji-t dengan tingkat kepercayaan 95%. Hasil penelitian menunjukkan bahwa variasi karakter anatomi talus dengan garis konsentris 5 memiliki ketebalan epidermis adaxial dan abaxial masing-masing adalah 20,05 μm dan 12,55 μm, sedangkan pada garis konsentris 7 memiliki ketebalan 28,33 μm dan 18 μm. Ketebalan talus dengan garis konsentris 5 dan 7 masing-masing adalah 99,44 μm, 114,77 μm. Diameter meduler dengan garis konsentris 5 dan 7 masing-masing adalah 37,88 μm, 45,5 μm. Diameter rata-rata tetra sporangia masing-masing dengan garis konsentris 5 dan 7 yaitu 25,66 μm, 35,66 μm. Talus P. australis Hauck berdasarkan garis konsentris 5 dan 7 memiliki perbedaan ukuran pada ketebalan epidermis adaxial, ketebalan epidermis abaxial, ketebalan talus, diameter meduler, dan diameter tetra sporangia. Implikasi penelitian ini sebagai database pada data dasar karakter anatomi P. australis yang dikaitkan denggan produktsi alginat dan data dasar taksonomi. ABSTRACT: Anatomical character data can be used to determine the productivity of P. australis Hauck's seaweed alginate content. Each thallus has a thallus size and the number of varied concentric lines. The aim of the research is to determine the anatomical characteristics of the Padina australis Hauck thallus. Seaweed sampling by purposive random sampling technique in Karang Tengah beach, Cilacap regency. Preparation of microscopic by paraffin method with safranin 1% in 70% alcohol. Parameters observed included thickness of the epidermis, size of a medullary cell, the thickness of thallus, and the size of tetra sporangia. The anatomical character data was analyzed by t-Test with a 95% confidence level. The result of the research showed that the anatomical character of the thallus with concentric line 5 had a thickness of adaxial and abaxial epidermis respectively is 20.05 μm and 12.55 μm, whereas in concentric line 7 had a thickness of 28.33 μm and 18 μm. The thickness of the thallus with concentric lines 5 and 7 respectively is 99.44 μm, 114.77 μm. Medullary diameter with concentric lines 5 and 7 respectively is 37,88 μm, 45,5 μm. The average diameter of tetra sporangia with concentric lines 5 and 7 respectively that is 25,66 μm, 35,66 μm. Thallus of P. australis Hauck based on concentric lines 5 and 7 has differences of sizes on the adaxial epidermal thickness, thickness of the abaxial epidermis, the thickness of the thallus, medullary diameter, and diameter of tetra sporangia. The implications anatomical characters associated with alginate productivity and taxonomic baseline data.

Leaf blade anatomy of the rare Siberian flora species Mertensia sibirica (L.) G. Don fil. (Boraginaceae)

The authors present the findings of a leaf blade anatomy study for the rare relict Siberian flora species Mertensia sibirica (L.) G. Don fil. (Boraginaceae). They collected samples for the study from natural habitats in Chita Region (Chikoy Range) and then planted them in the introduction area of the Siberian Botanic Garden (Tomsk) located in the southern taiga subzone of Western Siberia. The parameters of the photosynthetic and stomatal complex of M. sibirica were studied for the first time. It was found out that the rosette and cauline leaves of the species under study are hypostomatous, with an anomocytic stomatal complex. The epidermis is single-layer. On average, the adaxial epidermis has larger cells vs. abaxial epidermis. The leaf mesophyll is 242.90–369.90 µm thick, dorsiventral. The adaxial side of the leaf comprises glandular trichomes surrounded with pronounced rosettes of cells in the base part. The cauline leaf significantly differs from the rosette leaf in finer cells of its adaxial and abaxial epidermis (and, consequently, their larger number per 1 mm2), while the adaxial epidermal cells are thicker, and in a larger number of stomata in the abaxial epidermis. The palisade mesophyll in the cauline leaf is more developed vs. the rosette leaf, while the cells are longer and the palisade/spongy mesophyll ratio is higher. The rosette leaves have a more developed system of vascular tissues vs. cauline ones, as they play the main role in providing plants with water and nutrients. The contribution of the cauline leaf palisade mesophyll to the photosynthetic potential of M. sibirica is higher vs. that of the rosette leaf (the ratio between palisade and spongy mesophyll is 0.45 vs. 0.36, respectively), which characterizes the cauline leaf as more heliophytic. The stomatal complex and mesophyll parameters under study are primarily characterized by low variance. As for dermal tissue parameters, medium variance is typical of the thickness and size of the abaxial and adaxial epidermal cells. Coefficients of variation for the cells of the upper mesophyll layer (CV=31.2–41.6%) and the number of stomata on the lower epidermis of the rosette leaf (CV=21.5%) demonstrate medium and high variance. A very high coefficient of variation (116.2–174.0) is registered for the adaxial epidermis parameter characterizing the density of trichomes per 1 mm2. The study results were used to develop an optimal M. sibirica cultivation regime under conditions of introduction in the southern taiga subzone of Western Siberia.