Drought Response of Rice in Northeastern Thailand Assessed via Fourier Transform Infrared Spectroscopy

Drought isa major constraint in many rainfed areas and affects rice yield. We aimed to characterize the physiological changes in rice in response to drought using Fourier transform infrared (FTIR) spectroscopy. Eighty rice landrace seedlings were subjected to drought in the greenhouse using a PEG 6000. Physiological parameters, including total chlorophyll content, relative water content, electrolyte leakage, and biochemical changes were evaluated. Based on the FTIR results, the landraces were divided into three main groups: tolerant, moderately tolerant, and susceptible. Principal component analysis revealed spectral differences between the control and drought stress treatment groups. Lipid, pectin, and lignin content increased after drought stress. The biochemical components of plants at different drought tolerance levels were also compared. The lipid (CH2 and CH3), lignin (C=C), pectin (C=O), and protein (C=O, N–H) contents were the highest in the drought-tolerant cultivars, followed by the moderately tolerant and susceptible cultivars, respectively. Cultivar 17 and 49 were the most tolerant, and the functional groups were identified and characterized using FTIR. Overall, these results will be useful in selecting parental cultivars for rice breeding programs.

Structural Adaptation and Antioxidant Response of Guarianthe bowringiana (O’Brien) Dressler & W. E. Higgins (Orchidaceae Juss.) Seedlings During Ex Vitro Acclimatization

Guarianthe bowringiana is one of the oldest samples cultivated at NBG’s orchid unit glasshouses since 1970s. An efficient protocol for asymbiotic in vitro seed germination of G. bowringiana has previously been established. Given that acclimatization is a crucial step in micropropagation, this study assesses the structural adaptation and antioxidant response of G. bowringiana seedlings during ex vitro acclimatization to ex vitro conditions. The leaf surface micromorphology of the G. bowringiana juvenile plants propagated in vitro from seeds as well as the leaves of adult plants cultivated in glasshouse were analyzed using scanning electron microscopy. The levels of lipid peroxidation (TBARS level), superoxide dismutase (SOD) activity, and the photosynthetic activity were monitored for seven days from the transfer of seedlings from the in vitro cultivation vessels as they are markers indicating the response of the leaves of in vitro propagated G. bowringiana plants to oxidative stress during the early stages of acclimatization to ex vitro conditions. During the initial 2 days of the monitored acclimatization period (0–7 days), the level of photosynthetic pigments (chlorophyll a , b , and carotenoid content) increased, followed by an insignificant increase during the successive period (by the seventh day) of acclimatization. At the same time, the level of the tested antioxidant enzyme (SOD) exhibited an increasing trend throughout the acclimatization period. The SOD activities in the leaves of G. bowringiana seedlings were significantly affected when they were transferred from in vitro to ex vitro conditions due to drought stress. Thus, it was revealed that in the early stages of acclimatizing to the altered environments, G. bowringiana seedlings exhibited a rapid increase in photosynthetic pigments, superoxide dismutase activity, and lipid peroxidation levels after being transferred to ex vitro conditions. Comparison of the leaf micromorphologies of G. bowringiana plants grown under in vitro and those grown under ex vitro conditions revealed that leaf development had undergone significant changes during acclimatization to the altered conditions. In vitro to ex vitro transfer leads to a transient decrease in photosynthetic parameters.

Leaf Anatomical Adaptation Under Early Drought Stress of Sugarcane Cultivars – KKU-1999-02 and KKU-1999-03

Anatomical adaptation is an important feature that allows plants to mitigate drought stress. A comparative leaf anatomy of two drought-tolerant sugarcane cultivars, KKU-1999-02 and KKU-1999-03, was studied in early drought stress between 30 and 90 days after planting using peeling and freehand sectioning methods. KKU-1999-02 and KKU-1999-03 showed different anatomical adaptation features, such as increase in cuticle thickness, bulliform cell size, vascular bundle, and stomatal density, and decreases in leaf thickness and stomatal size. KKU-1999-02 showed more remarkable anatomical changes than KKU-1999-03. The results provide important information that can be applied in combination with other agronomic traits in sugarcane breeding programs to expand the adaptation devices of tolerant cultivars under preliminary drought stress.

Micromorphology and Anatomy of the Flowers in Clivia spp. and Scadoxus multiflorus (Haemantheae, Amaryllidaceae)

The general morphology, micromorphology, and anatomy of the flowers of Clivia miniata , Clivia nobilis , and Scadoxus multiflorus were studied using light microscopy. The studied species have large syntepalous and trimerous flowers, short floral tubes with adnate stamens, and inferior ovaries that develop baccate fruit. The gynoecium in the studied species consists of synascidiate, symplicate, and hemisymplicate zones. The style is composed of postgenitally fused carpels. The few ovules are located in a locule in the synascidiate and symplicate zones in C. miniata and C. nobilis , whereas in S. multiflorus , solitary ovules occupy the synascidiate zone in each locule. The septal nectaries are located in the hemisymplicate zone and occupy the uppermost 29% to 56% of the ovary height. Septal nectaries are of the nonlabyrinthine lilioid-type, covered with secretory tissue only in its lower portion. Nectary channels are apical or subapical and open near the style base. A common pattern of the venation of the floral parts was observed in all species: Tepal traces and stamen traces were fused in the ovary wall, the style was supplied by dorsal carpellary bundles, and ovules were supplied by ventral carpellary bundles entering the ovary from the bottom. The observed gynoecium inner structure provides adaptations for the development of fleshy fruit, with thickened parenchymous ovary wall, ovary base, and ovary roof, and numerous branched vascular bundles in the ovary wall around locules.

Morphological Variability of Generative Individuals of Rare Decorative Ephemeroids of the Northern Tien Shan As Evidence of Their Adaptive Potential

We assessed the adaptive potential of two rare decorative species listed in the Red Book of Kazakhstan : Tulipa tarda Stapf (Liliaceae) and Gymnospermium altaicum (Pall.) Spach (Berberidaceae) by studying the morphological variability of generative individuals of the species. Our studies were carried out in natural populations in the Northern Tien Shan and introduced populations of the botanical garden and urban green areas of Almaty. These species showed a high degree of adaptation under the conditions of the introduction. Moreover, Gymnospermium altaicum , accidentally introduced into the urban green area of Bukhar Zhyrau Boulevard (Almaty), had formed a naturalized population that persisted for more than 8 years. The naturalized population of Tulipa tarda in the botanical garden (Almaty), introduced more than 20 years ago by one of the authors of this article, has been in existence even longer. In the latter case, individuals of seed origin showed higher adaptive capabilities than those transferred by the bulbs of generative plants.

Herbicide Potential of Selected Essential Oils From Plants of Lamiaceae and Asteraceae Families

Essential oils from Monarda fistulosa L., Satureja pilosa Vel., Origanum vulgare subsp. hirtum Ietswaart. (Greek oregano), Micromeria dalmatica Benth., Thymus longedentatus (Degen & Urum.) Ronniger, and Artemisa campestris L. were evaluated as inhibitors of seed germination in target plants Lolium perenne L. and Trifolium pratense L. using in vitro assays. The essential oils were applied on the seeds as aqueous solutions at concentrations ranging from 0.5–3.0 µL/mL. Complete inhibition was established at a concentration of 1.5 µL/mL with the most effective essential oils. Oregano oil was evaluated for its inhibitory activity on seed germination under field conditions; the essential oil was applied as an aqueous solution at concentrations of 3, 5, and 10 µL/mL on superabsorbent Terawet. The mass obtained was mixed with the seeds of the target plants and planted in a field. After 1 month, the results were evaluated based on the weight of the aerial parts of the plants from control and experimental areas. At the highest concentration studied, the weight of the plants was 77% lower in the experimental areas than in the controls. The chemical composition of the essential oils was analyzed using gas chromatography–mass spectrometry. The results showed that carvacrol-rich essential oils had a strong inhibitory effect on seed germination. The inclusion of the essential oil on a superabsorbent was a good way to preserve its herbicidal activity under field conditions as this prevented its rapid evaporation.

Preservation of Features of Anatomical Polymorphism of Deschampsia antarctica É. Desv. (Poaceae) During In Vitro Clonal Reproduction

We studied the anatomical features of the leaf structure of Deschampsia antarctica É. Desv. (Poaceae) obtained from seeds collected from different habitats of the maritime Antarctic. These plants have been maintained in culture in vitro for more than 7 years. The plants include stable chromosome forms comprising diploids (2 n = 26), a diploid plant with B-chromosomes (2 n = 26 + 0–3B), a triploid with rearranged chromosome morphology, and myxoploids with different ratios of diploid and nondiploid cells in the root meristem. The D. antarctica plants that were studied generally had a similar anatomical structure in culture in vitro and in nature. At the same time, plants of different cultivated genotypes also displayed their own leaf structure features. In particular, qualitative features included asymmetric four-ribs and five-rib leaves instead of typical three-rib leaves for some genotypes, some individuals characterized by the presence of unicellular nonglandular pointed trichomes on an adaxial side, differences in vascular bundle sheath, and other features. No clear dependence of the anatomical structural features on the chromosomal status of the studied genotypes was evident. At the same time, differences were evident in traits that included the number of stomata, thickness of the outer cell walls of the epidermis, bundles sheath state, number of leaf ribs, and the persistent presence of trichomes under prolonged in vitro cloning. The findings indicate that D. antarctica plants collected from different locations of the maritime Antarctic for long-term cultivation in vitro under standard cultivation conditions retain the anatomical characteristics of the wild plants. The polymorphism of in vitro-cultivated plants is not related to the polymorphism of their karyotype, but is apparently due to the heterogeneity of the original plants and possibly the epigenetic fixation of a number of anatomical features produced in the natural microhabitats of D. antarctica populations.

Micromorphological Characteristics of Fruit Surfaces of Some Usable Species of the Genus Valeriana (Valerianaceae) Among Ukrainian Flora

The micromorphological features of the fruit surfaces of nine species of Ukrainian flora, namely Valeriana tuberosa L., Valeriana tripteris L., Valeriana rossica P. Smirn., Valeriana stolonifera Czern., Valeriana grossheimii Worosch, Valeriana sambucifolia Mikan fil., Valeriana officinalis L. s. str., Valeriana wolgensis Kazak. [ Valeriana officinalis var. nitida (Kreyer) Rostanski], and Valeriana simplicifolia (Rchb.) Kabath, were examined. Depending on the presence and localization of pubescence on the surface of the fruit, three groups of species were distinguished: those with glabrous fruits, those with fruits pubescent only on the adaxial side, and those with fruits pubescent on both sides. Scanning electron microscopy revealed the additional characteristics of the fruits (microsculpture of the fruit surface, shape of cuticular formations on the surface of the outer periclinal walls of epidermal cells and on the surface of hairs, and structure of the stomatal complex), which were useful for the identification of the species. At the supraspecific level, the revealed features of the fruit surfaces somewhat overlapped and could be used to identify series and sections only as additional features. Based on the studied samples from herbarium material (KW), V. officinalis var. nitida was considered synonymous with V. wolgensis since there were no micromorphological differences between their fruits. The detailed micromorphological characteristics of the fruit surfaces of all the studied species can be used for further comparative morphological investigations of different aerial parts to identify stable features independent of geographic and ecological conditions.

Morphological Features of Fruits and Seeds of Some Species of the Genus Crataegus L. of the Flora of Ukraine

The genus Crataegus L. is one of the largest species in the family Rosaceae Juss. The fruits are used as medicinal raw materials ( Crataegus fructus ), as they contain a set of biologically active compounds. The genus is voluminous and taxonomically problematic due to significant variability, hybridization, apomixis, and polyploidy. As a result, it is difficult to determine the species of the genus. Species of the genus have a number of diagnostic features, one of which is a distinct fruit with seeds. The aim of our study was to identify and compare the diagnostic features of the fruits of seven species of the genus Crataegus flora of Ukraine, which are most often used as medicinal raw materials and are the most common in Ukraine – Crataegus laevigata , C. monogyna , C. pentagyna , C. pseudokyrtostyla , C. sanguinea , C. fallacina , and C. rhipidophylla . The study was performed using scanning and digital microscopy, and descriptions were made by standard methods. As a result, we identified features that clearly distinguished the studied species from each other. We identified mature fruits that contain only one pyrene ( C. monogyna , C. pseudokyrtostyla , C. fallacina , and C. rhipidophylla ), and several pyrenes ( C. laevigata , C. pentagyna , and C. sanguinea ) among the studied species of the genus. The studied species are characterized by spherical and ellipsoidal fruits. The predominant color is fulvous/brown with different shades, but almost-black fruits of the species C. pentagyna are well distinguished. Fruits of all studied species of the genus are fleshy, except C. sanguinea , which is floury. The species is characterized mainly by yellow flesh fruits, except C. pentagyna , which has ribbed fruits. The fruits of C. monogyna plants differ from those of other studied species by the spinous-tuberous surface relief. Pyrenes of triangular shape are observed only in C. pentagyna . We suggest that these features can be used as additional diagnostic tools to determine the species of the genus Crataegus flora in Ukraine.

Morpho-Anatomy of the Gynoecium and Fruit in Three Ornamental Members of Campanuloideae (Campanulaceae)

Gynoecium and fruit micromorphology and anatomy were studied using light microscopy in three species of Campanuloideae belonging to the tribes Cyanantheae ( Platycodon grandiflorus ), Wahlenbergieae ( Jasione montana ), and Campanuleae ( Adenophora liliifolia ) of the native and cultivated flora of Ukraine, to elucidate structural adaptations for fruit dehiscence. The studied species differed in flower/fruit orientation, carpel number, ovary insertion, and capsule-opening position, and the information provided a background for the discovery of common anatomical features influencing fruit dehiscence. In the studied species, the synascidiate and symplicate zones in the ovary and prominent placentae were found to be located near the mid-region of the ovary. The distinct innervation of the ovary wall and ovules was described. In P. grandiflorus , the septa and fruit wall contained a lignified parenchyma in a subepidermal position, while in J. montana and A. liliifolia , lignification was observed only in proximal portions of the septa, above the placenta ( J. montana ), or was noted as a narrow strand from the ovary base to the mid-region, called “axicorn” ( A. liliifolia ). In all the studied species, unlignified endocarpium was detected. The semi-inferior capsule of P. grandiflorus has been defined as a capsule of the Forsythia -type, with a sclerenchymatous layer in the inner zone of the mesocarpium. In J. montana and A. liliifolia , a new histogenetic type of capsule is described as Campanula -type, without lignified layers in the fruit wall and with lignified tissue in the septa, which enabled dehiscence. Our study proposed for the first time the classification of the capsules found in the studied species based on the development of openings in the superior or inferior regions of the fruits. The upright fruits of P. grandiflorus and J. montana reveal incomplete dorsiventral dehiscence in the superior region of the fruit, while dehiscence of pendent fruits of A. liliifolia is hippocrepiform-septifragal interlocular and occurs in the inferior region of the fruit at its base, as revealed previously in Campanula latifolia fruit.