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Mountainous ecosystems are experiencing rapid shifts in distribution patterns and community structure due to the impacts of climate change and vegetation dynamics. This study offers a comprehensive insight into the adaptive mechanisms of Panicum antidotale to varying elevations within the Pothohar Plateau, shedding light on its survival strategies in climate-affected regions. The findings reveal that populations at lower elevations exhibit maximum height, leaf area, shoot length, and fresh weight, whereas those at higher elevations display significant decrease in these parameters. Moreover, a significant decline in species density, frequency and cover is evident at high elevation. High-elevation populations demonstrate decreased photosynthetic traits, including chlorophyll, carotenoid, and Na and Ca content. Furthermore, there are notable variations in the antioxidant enzyme activity across elevation gradients. Populations at lower elevations exhibit higher activities of superoxide dismutase and peroxidase. Across the gradient, there were significant reductions in root and stem radius, sclerenchyma thickness, bulliform cell size, metaxylem vessels, and phloem area. Populations at moderate elevations displayed thicker lamina and epidermis, larger cortical cells, wider xylem vessels, and increased phloem area; however, these traits declined at higher elevations. High-elevation populations showed thicker lamina and epidermis, extensive sclerenchyma, greater cortical cell area, and higher stomatal density. Photosynthetic traits and enzymatic activity were major contributors at moderate elevations while stem and leaf traits were significantly changed at high elevations. Overall, this research contributes significantly to the broader knowledge of plant adaptation in mountainous ecosystems and stresses the importance of considering elevation as a critical factor in ecological studies.

Parthenium weed poses significant threats to cropping systems, socioeconomic structures, and native ecosystems. The pronounced impact is primarily attributed to its rapid and efficient invasion mechanism. Despite that the detrimental effects of Parthenium weed are widely acknowledged, an in-depth scientific comprehension of its invasion mechanism, particularly regarding modifications in structural and functional attributes under natural conditions, is still lacking. To bridge this knowledge gap and formulate effective strategies for alleviating the adverse consequences of Parthenium weed, a study was conducted in the more cultivated and densely populated areas of Punjab, Pakistan. This study was focused on fifteen distinct populations of the star weed (Parthenium hysterophorus L.) to investigate the factors contributing to its widespread distribution in diverse environmental conditions. The results revealed significant variations in growth performance, physiological traits, and internal structures among populations from different habitats. The populations from wastelands exhibited superior growth, with higher accumulation of soluble proteins (TSP) and chlorophyll content (Chl a&b, TChl, Car, and Chl a/b). These populations displayed increased root and stem area, storage parenchyma, vascular bundle area, metaxylem area, and phloem area. Significant leaf modifications included thicker leaves, sclarification around vascular bundles, and widened metaxylem vessels. Roadside populations possessed larger leaf area, enhanced antioxidant activity, increased thickness of leaves in terms of midrib and lamina, and a higher cortical proportion. Populations found in agricultural fields depicted enhanced shoot biomass production, higher levels of chlorophyll b, and an increased total chlorophyll/carotenoid ratio. Additionally, they exhibited increased phloem area in their roots, stems, and leaves, with a thick epidermis only in the stem. All these outcomes of the study revealed explicit structural and functional modifications among P. hysterophorus populations collected from different habitats. These variations were attributed to the environmental variability and could contribute to the widespread distribution of this species. Notably, these findings hold practical significance for agronomists and ecologists, offering valuable insights for the future management of Parthenium weed in novel environments and contributing to the stability of ecosystems. [ABSTRACT FROM AUTHOR]

Parthenium weed poses significant threats to cropping systems, socioeconomic structures, and native ecosystems. The pronounced impact is primarily attributed to its rapid and efficient invasion mechanism. Despite that the detrimental effects of Parthenium weed are widely acknowledged, an in-depth scientific comprehension of its invasion mechanism, particularly regarding modifications in structural and functional attributes under natural conditions, is still lacking. To bridge this knowledge gap and formulate effective strategies for alleviating the adverse consequences of Parthenium weed, a study was conducted in the more cultivated and densely populated areas of Punjab, Pakistan. This study was focused on fifteen distinct populations of the star weed (Parthenium hysterophorus L.) to investigate the factors contributing to its widespread distribution in diverse environmental conditions. The results revealed significant variations in growth performance, physiological traits, and internal structures among populations from different habitats. The populations from wastelands exhibited superior growth, with higher accumulation of soluble proteins (TSP) and chlorophyll content (Chl a&b, TChl, Car, and Chl a/b). These populations displayed increased root and stem area, storage parenchyma, vascular bundle area, metaxylem area, and phloem area. Significant leaf modifications included thicker leaves, sclarification around vascular bundles, and widened metaxylem vessels. Roadside populations possessed larger leaf area, enhanced antioxidant activity, increased thickness of leaves in terms of midrib and lamina, and a higher cortical proportion. Populations found in agricultural fields depicted enhanced shoot biomass production, higher levels of chlorophyll b, and an increased total chlorophyll/carotenoid ratio. Additionally, they exhibited increased phloem area in their roots, stems, and leaves, with a thick epidermis only in the stem. All these outcomes of the study revealed explicit structural and functional modifications among P. hysterophorus populations collected from different habitats. These variations were attributed to the environmental variability and could contribute to the widespread distribution of this species. Notably, these findings hold practical significance for agronomists and ecologists, offering valuable insights for the future management of Parthenium weed in novel environments and contributing to the stability of ecosystems.

Chrysopogon serrulatus (false beard-grass) is a dominant component of vegetation in the foothills of the Himalayas. To study whole plant morphology, individuals of C. serrulatus were collected from three plots at each of six locations spanning from 400 to 1,400 m. The population colonizing the highest elevation showed noticeable morphological modifications in different plant organs. Roots showed increased xeromorphy, specifically increased metaxylem number and area. In the stem, especially outside of the vascular tissue, there was intensive sclerification indicative of increased xeromorphy as a survival strategy. At the highest elevation, leaves were wider; aerenchyma formation and increased sclerification were noted in the leaf sheath; and a greater proportion of storage parenchyma was observed in the leaf blade, all indicators of succulence. In contrast, leaves at lower elevations had xeric morphological features such as increased epidermal thickness, sclerification and more developed metaxylem area. In conclusion, shifting of morphological features in below- and above-ground plant parts of C. serrulatus were linked to shifts in environmental factors along this elevation gradient, thus enabling the successful distribution of this species along this elevation gradient. [ABSTRACT FROM AUTHOR]

Salt-accumulator species are of great interest for the phytoremediation of salt-affected soils to reclaim soil salinization, a major constraints causing germination retardation and growth restriction of plants as well as habitat degradation. Higher biomass production at ECe 23–36 dS m−1 indicated that this species grows better in high to moderate salinity that was linked to osmotic adjustment through higher ion accumulation (Na+, Cl‒, and Ca2+) and organic osmolytes (free amino acids and proline). Plants from highly and moderately saline habitats exhibited broader metaxylem vessels, which was associated with eased conduction of solutes leading to better growth. Leaf anatomical characteristics generally increased with increasing salinity except at the highest ECe 55 dS m−1. The increased leaf lamina thickness contributed to succulence because of increased storage parenchymatous spongy tissues (that can store high amounts of water), water contents and it is a reflection of maintaining ion homeostasis and colonizing hyper-saline soil. Reduced stomatal density and area under high salinity are critical to cope with environmental hazards. Under high salinity, compartmentalization of excessive Na+ and Cl− ions and accumulation of compatible osmolytes are directly related to high degree of salinity tolerance, and hence are useful for phyto-amelioration of salinity-impacted lands. Salinity tolerance mechanism in Suaeda vera have been explored extensively, but these mechanisms have not been addressed in the context of soil-plant interaction and functioning connection between structural and functional features with respect to phytoremediation. This work aims to provide mechanistic insight into how different morphological and physio-anatomical mechanisms in differently adapted population of Suaeda vera operate in coordinated manner to maintain ionic homeostasis under high salinity that are useful for phytoremediation. [ABSTRACT FROM AUTHOR]

Key messages: The endo-dormant bud scales of walnut have storage parenchyma cells with thickened walls. During bud dormancy release, cell wall hydrolytic enzymes mobilize pectin and hemicellulose reserves of these cells to fuel bud break. Cell wall hydrolytic enzymes might define specific stages of bud dormancy release. Bud dormancy release is important in woody plants as it is linked to final biomass and yield. This process requires enzyme activities which affect the bud cell wall physico-chemical properties, however, little information is available. Accordingly, the activities of some cell wall hydrolytic enzymes were studied during endo-dormancy release in lateral buds of two Persian walnut (Juglans regia L.) cultivars having low ('Serr') and high ('Hartley') chilling requirements (CRs). Buds were collected monthly from the leaf shedding stage (November) till bud break and used for enzymatic analysis. In both cultivars, the activities of 1,4-β-D-glucanase, xylanase, mannanase and pectinase increased during dormancy release. In 'Serr', first rises in mannanase and pectinase activities occurred before transition to eco-dormancy (January) and the second rises occurred before bud break (March). Similarly, in 'Hartley', first rise in mannanase activity observed before transition to eco-dormancy (February) and the second rise before bud break (April). 'Serr' buds also displayed significant increase in the activities of hemicellulases and pectinase earlier than 'Hartley', however, the latter showed quantitatively higher means for the enzymatic activities. Endo-dormant bud scales had very thick-walled storage parenchyma cells which turned into thinner-walled ones during bud break, suggesting cell wall polysaccharide mobilization by hemicellulases and pectinases. Thus, the activation of cell wall hydrolytic enzymes during endo-dormancy release may contribute to the bud scale cell wall carbohydrate reserve mobilization and/or growth-associated wall relaxation in preparation for bud break. Furthermore, buds from low CR plants may show earlier activation of cell wall-loosening mechanisms during dormancy release. [ABSTRACT FROM AUTHOR]

We investigated changes in plant morphology, anatomy and physiology in a commonly occurring weed, Euphorbia helioscopia L. due to exposure to post‐emergence herbicides. Weed plants were sprayed with one of the following herbicides: pyrimidinyl sulphonylharnstoffe (PS), tribenuron‐methyl (TM), fluroxypyr‐methyl tribenuron‐methyl (FMTM) and bromoxynil (Br). The PS treatment significantly decreased plant height, promoted initiation of side branches and induced a prostrate habit. A specific response of root anatomy to PS and Br treatments was the high proportion of storage parenchyma. The Br‐treated plants showed thickest roots with a significantly large storage parenchyma, not only in the central portion of roots, but also in the cortical parenchyma outside the vascular tissue. A high proportion of xylem in the central portion of roots in the TM or FMTM‐treated plants provides a strong survival response in E. helioscopia. Disintegration of stem cortical parenchyma is the most prominent response of E. helioscopia when treated with a herbicide like PS or FMTM. Survival against these herbicides relates to a complete ring of vascular bundles and intact cortical parenchyma outside the vascular tissue. Increased leaf thickness was recorded in most of the cases except in the FMTM‐treated plants. The PS‐treated plants showed midrib thickness with two distinct vascular bundles. The cortical region, however, was found to be damaged by tissue collapse forming a large lysigenous aerenchyma. Euphorbia helioscopia had altered morphology, anatomy and physiology in response to herbicide application, which changed its growth in the field. To achieve control of this weed species, alternative strategies or higher doses of herbicide should be applied. Further research is required to determine the interaction of surviving weed plants with the crop. [ABSTRACT FROM AUTHOR]

Abstract Background Saccharum species such as sugarcane and energy cane are key players in the expanding bioeconomy for sugars, bioenergy, and production of high-value proteins. Genomic tools such as culm-regulated promoters would be of great value in terms of improving biomass characteristics through enhanced carbon metabolism for sugar accumulation and/or fiber content for biofuel feedstock. Unlike the situation in dicots, monocot promoters currently used are limited and mostly derived from highly expressed constitutive plant genes and viruses. In this study, a novel promoter region of Sugarcane bacilliform virus (SCBV; genus Badnavirus, family Caulimoviridae), SCBV21 was cloned and mapped by deletion analysis and functionally characterized transiently in monocot and dicot species and stably in sugarcane. Results In silico analysis of SCBV21 [1816 base pair (bp)] identified two putative promoter regions (PPR1 and PPR2) with transcription start sites (TSS1 and TSS2) and two TATA-boxes (TATAAAT and ATATAA), and several vascular-specific and regulatory elements. Deletion analysis revealed that the 710 bp region spanning PPR2 (with TSS2 and ATATAA) at the 3′ end of SCBV21 retained the full promoter activity in both dicots and monocots, as shown by transient expression of the enhanced yellow fluorescent protein (EYFP) gene. In sugarcane young leaf segments, SCBV21 directed a 1.8- and 2.4-fold higher transient EYFP expression than the common maize ubiquitin 1 (Ubi1) and Cauliflower mosaic virus 35S promoters, respectively. In transgenic sugarcane, SCBV21 conferred a preferential expression of the β-glucuronidase (GUS) gene in leaves and culms and specifically in the culm storage parenchyma surrounding the vascular bundle and in vascular phloem cells. Among the transgenic events and tissues characterized in this study, the SCBV21 promoter frequently produced higher GUS activity than the Ubi1 or 35S promoters in a manner that was not obviously correlated with the transgene copy number. Conclusions The newly developed plant viral SCBV21 promoter is distinct from the few existing SCBV promoters in its sequence and expression pattern. The potential of SCBV21 as a tissue-regulated promoter with a strong activity in the culm vascular bundle and its storage parenchyma makes it useful in sugarcane engineering for improved carbon metabolism, increased bioenergy production, and enhanced stress tolerance.

The study is a continuation of a series of experiments to identify the role of sucrose in the anomalous morphogenesis of conducting tissues of deciduous woody plants. Previously it was found that the exposure of the trunk tissue to solutions with a high concentration of sucrose causes birch and alder to form xylem, which has common features with the figured woods of these species, while aspen xylem does not differ in structure from typical wood. In this paper, the effect of sucrose solutions of various concentrations on the phloem formation is analyzed. In alder and aspen, high concentrations of sucrose (10% and 20%) was found to have no effect on the structure of the late phloem; the reaction of these species was manifested through a change in the functional state of parenchyma cells (an appearance of large central vacuole, accumulation of starch). At the same time there was a tendency to enhance parenchymatization of the birch late phloem with increasing concentration of sucrose in the solution, but the observed differences were not significant. In all studied species, in the variants with a sucrose concentration 1% - 5%, sclerenchyma elements differentiated in the conductive phloem, the latter is a structural anomaly for birch, but typical for alder and aspen. It was concluded that with an increase in the concentration of sugars in the cambial zone of birch above a certain threshold value, their utilization within the framework of the previous structure of tissues is not enough, and the formation of new storage cells and sclereids occurs. It has been suggested that alder and aspen have mechanisms that maintain the level of sucrose within the limits necessary for normal phloemogenesis, one of which, apparently, is the formation of thick-walled sclerenchyma elements. The difference in the metabolites stored by parenchyma cells under the experimental conditions is only a reason to believe that a large excess of sugars is normally absent in the tissues of the trunk of grey alder and aspen.

Efforts to breed salt tolerant crops could benefit from investigating previously unexplored traits. One of them is a tissue succulency. In this work, we have undertaken an electrophysiological and biochemical comparison of properties of mesophyll and storage parenchyma leaf tissues of a succulent halophyte species Carpobrotus rosii ("pigface"). We show that storage parenchyma cells of C. rossii act as Na+ sink and possessed both higher Na+ sequestration (298 vs. 215 mM NaCl in mesophyll) and better K+ retention ability. The latter traits was determined by the higher rate of H+‐ATPase operation and higher nonenzymatic antioxidant activity in this tissue. Na+ uptake in both tissues was insensitive to either Gd3+ or elevated Ca2+ ruling out involvement of nonselective cation channels as a major path for Na+ entry. Patch‐clamp experiments have revealed that Caprobrotus plants were capable to downregulate activity of fast vacuolar channels when exposed to saline environment; this ability was higher in the storage parenchyma cells compared with mesophyll. Also, storage parenchyma cells have constitutively lower number of open slow vacuolar channels, whereas in mesophyll, this suppression was inducible by salt. Taken together, these results provide a mechanistic basis for efficient Na+ sequestration in the succulent leaf tissues. This work explored a mechanistic basis for Na+ sequestration in the succulent leaf tissues from the halophyte species Carpobrotus rosii. It is shown that the storage parenchyma in Carpobrotus act as Na+ sink and also possessed better K+ retention ability, due to higher rate of H+‐ATPase operation and higher nonenzymatic antioxidant activity in this tissue. The storage parenchyma cells also had constitutively lower number of open slow vacuolar channels, thus preventing futile Na+ leak from the vacuole into the cytosol. [ABSTRACT FROM AUTHOR]

Stem segments of aseptically grown potato {Solatium tuberosum L. cv. Zarevo) were cultivated for 4 weeks under laboratory conditions and were then grown for 8 d on board the “Mir” orbital space station. Timing was such that minitubers initiated and developed during the 8 d on the “Mir”. Under space flight and stationary conditions, spherical minitubers were formed with no statistically significant differences in either the frequency of tuber formation or tuber size. These observations are the first to document the formation of vegetative reproductive organs and of well developed amylogenic storage tissue during the microgravity conditions of orbital space flight. In these minitubers, a majority of the starch was stored in parenchyma, with numerous amyloplasts per cell. In space flight tissue, however, grain size of starch was decreased and lamellae within the amyloplasts was locally enlarged. Furthermore, mitochondria of these tissues were characterized by increased matrix density and well developed cristae. [ABSTRACT FROM AUTHOR]

Interdiffusion coefficients of K and Na for tangential transport through cell walls were found to be independent of ion strength and only moderately (c. 50%) lower than values known for diffusion in water. Although at low salt concentrations alkali ion exchange diffusion on the cell wall pathway is facilitated by accumulation of diffusion species in the Donnan space, at all concentrations the resistance of the whole tissue for apoplastic cation exchange diffusion remained significantly higher than that of unstirred liquid of equal thickness, as the area fraction of the cell wall pathway in the parenchyma is small. [ABSTRACT FROM AUTHOR]

The ultrastructure of the endoplasmic reticulum (ER) in storage parenchyma cells in the cotyledons of mung beans ( Vigna radiata L.) was examined during germination and seedling growth. Two different methods were used to visualize the ER: thin (0.08 μm) sections of tissue fixed in formaldehyde and glutaraldehyde and post-fixed with osmium tetroxide, and thick (1 μm) sections of tissue fixed in buffered aldehyde and post-fixed with zinc iodide-osmium tetroxide (ZIO). Changes in relative amounts of ER were quantified by morphometry (stereology). The ER occurs in two forms: a cisternal form with associated ribosomes which can be seen at all stages from imbibition to cotyledon senescence, and a tubular form which initially has associated ribosomes. Stereoscopic images of thick sections of cotyledons of 2-day-old seedlings show that the tubular ER consists of a three-dimensional array of interconnecting tubules which have numerous connections with the cisternal ER. The network of tubules and cisternae extends throughout the cytoplasm enveloping the protein bodies. Germination and seedling growth are accompanied by a reduction in the total volume occupied by the ER. This reduction is the result of a preferential loss of tubular ER and occurs largely before protein mobilization. Cisternal ER decreases during the first 48 h of imbibition and seedling growth, but storage cells subsequently show an increase in cisternal ER just prior to and during the period of protein mobilization. Cisternal ER remains conspicuous during the last phase of reserve mobilization when starch is broken down and the cells are starting autophagy. [ABSTRACT FROM AUTHOR]

Potential pathways for sucrose unloading in the potato tuber were examined by light and electron microscopy. Abundant plasmodesmata connected sieve elements with surrounding parenchyma elements and also sieve elements with companion cells. Plasmodesmata were rarer, however, between companion cells and parenchyma elements. These observations suggest that sucrose may leave the sieve elements and enter the storage parenchyma cells directly via the symplast and that transport through the companion cell may not be a prerequisite for unloading. Plasmodesmata, grouped together in primary pit fields, were also abundant between storage cells, and isolated storage cells, separated enzymically, showed considerable variation in plasmodesmatal distribution between cells and also on different faces of a single cell. Deposition of starch was found to occur in the tuber cortex while an endodermis with Casparian strip was present external to the phloem, suggesting that assimilates initially enter the cortical storage cells by an entirely symplastic pathway. The possible involvement of ATPase in the unloading process was examined cytochemically, using a lead-salt precipitation method. By contrast with previous findings for phloem no evidence was found for ATPase activity that was unique to the sieve element-companion cell complex. The present observations favour the view that phloem unloading in the potato tuber is a symplastic and passive process. [ABSTRACT FROM AUTHOR]

Background: Saccharum species such as sugarcane and energy cane are key players in the expanding bioeconomy for sugars, bioenergy, and production of high-value proteins. Genomic tools such as culm-regulated promoters would be of great value in terms of improving biomass characteristics through enhanced carbon metabolism for sugar accumulation and/or fiber content for biofuel feedstock. Unlike the situation in dicots, monocot promoters currently used are limited and mostly derived from highly expressed constitutive plant genes and viruses. In this study, a novel promoter region of Sugarcane bacilliform virus (SCBV; genus Badnavirus , family Caulimoviridae ), SCBV21 was cloned and mapped by deletion analysis and functionally characterized transiently in monocot and dicot species and stably in sugarcane., Results: In silico analysis of SCBV21 [1816 base pair (bp)] identified two putative promoter regions (PPR1 and PPR2) with transcription start sites (TSS1 and TSS2) and two TATA-boxes (TATAAAT and ATATAA), and several vascular-specific and regulatory elements. Deletion analysis revealed that the 710 bp region spanning PPR2 (with TSS2 and ATATAA) at the 3' end of SCBV21 retained the full promoter activity in both dicots and monocots, as shown by transient expression of the enhanced yellow fluorescent protein ( EYFP ) gene. In sugarcane young leaf segments, SCBV21 directed a 1.8- and 2.4-fold higher transient EYFP expression than the common maize ubiquitin 1 ( Ubi1 ) and Cauliflower mosaic virus 35S promoters, respectively. In transgenic sugarcane, SCBV21 conferred a preferential expression of the β-glucuronidase ( GUS ) gene in leaves and culms and specifically in the culm storage parenchyma surrounding the vascular bundle and in vascular phloem cells. Among the transgenic events and tissues characterized in this study, the SCBV21 promoter frequently produced higher GUS activity than the Ubi1 or 35S promoters in a manner that was not obviously correlated with the transgene copy number., Conclusions: The newly developed plant viral SCBV21 promoter is distinct from the few existing SCBV promoters in its sequence and expression pattern. The potential of SCBV21 as a tissue-regulated promoter with a strong activity in the culm vascular bundle and its storage parenchyma makes it useful in sugarcane engineering for improved carbon metabolism, increased bioenergy production, and enhanced stress tolerance.