Dead Stem Research Articles

Isolation, Identification, and Pathogenicity of Sclerotium rolfsii (Sacc.) Causing Collar Rot in Chickpea

Sclerotium rolfsii (Sacc.) is a detrimental soil-borne fungus responsible for collar rot in chickpea. We conducted an experiment including the isolation, purification, identification, and pathogenicity assessment of fungi from infected plant materials. The plants appear typical symptoms such as complete leaf abscission, browning, desiccation, and often remain attached to the dead stem. The mycelium of the pathogen proliferates over the affected tissue and adjacent soil, creating a white mat of mycelial threads interspersed with characteristic sclerotia, ranging from brown to dark brown and resembling mustard seeds in size. Collar rot samples were collected and sent to the laboratory for isolation. The fungus was isolated and grown on Potato Dextrose Agar (PDA) media. The pathogenicity tests were validated by adhering to Koch's postulates and used three inoculation techniques. The seed and soil inoculation approach demonstrated significant efficacy, resulting in the greatest disease incidence (71.05%) and reduced seed germination (74.90%). This research highlights the impact of S. rolfsii on chickpea crops, offering insights into its pathogenicity and management strategies. Understanding its infection mechanisms can help develop effective control measures to enhance chickpea yield and sustainability.

Tetraploa wurfbainiae sp. nov. (Tetraplosphaeriaceae, Pleosporales) isolated from Wurfbainia villosa in Guangdong, China

ABSTRACT During a survey for microfungi associated with traditional medicinal plants in Guangdong Province, China, an interesting species in the Tetraplosphaeriaceae was isolated from the dead stem of Wurfbainia villosa (Zingiberaceae). The new collection is characterised by brown to dark brown, cylindrical to ovate, four-columned conidia, mostly with four straight or slightly flexuous, smooth, and long apical appendages. The phylogenetic analysis of the combined dataset of internal transcribed spacer (ITS), large subunit nuclear rDNA (LSU), the partial translation elongation factor 1-α (tef1-α), and β-tubulin (tub2) further indicated that the new collection forms a distinct branch in Tetraploa and clusters as a sister taxon with T. dwibahubeeja. Thus, we introduce a new species, Tetraploa wurfbainiae, based on distinct morphology and multi-locus phylogeny, accompanied by a description, illustration, and morphological comparison with related taxa. This is the first report of Tetraploa species on the medicinal plant W. villosa. This study enhances our understanding of the fungal species associated with the medicinal plant W. villosa.

Ecological significance of marcescence in Himalayan plants: Why is standing dead phytomass more important in demanding, resource‐limited environments?

Abstract Understanding mechanisms allowing plants to thrive in challenging conditions is critical for predicting their responses to global environmental change. An often overlooked ecological adaptation is marcescence, where leaves and stems are retained beyond their typical shedding time, with implications for nutrient recycling and carbon sequestration. Marcescence can be expected in plants with conservative resource‐use strategies, especially in environments with limited resources and marked seasonality, such as deserts and alpine regions. However, the extent to which marcescence occurs in different taxa across different habitats and its relationship to seasonality and plant functioning as reflected in ecophysiological traits remains understudied. We studied 600 individuals across 40 Himalayan herb species found in desert, steppe, alpine and subnival habitats, spanning 3000–5400 m elevation. Marcescence was observed in 37 of the 40 species evaluated, with 57% of the sampled individuals displaying dead phytomass, indicating the widespread nature of this phenomenon in Himalayan ecosystems. Environment and plant traits emerged as significant factors influencing the amount of dead‐standing biomass. These findings remained robust after accounting for intraspecific variation and phylogenetic inertia. Desert and steppe species exhibited greater marcescent biomass, characterized by 10‐fold more dead stem biomass than alpine and subnival plants. In contrast, the proportion of dead phytomass increased with elevation due to increased dead leaf fraction. Taller desert species with heavily lignified stems and limited nitrogen and phosphorus content had high levels of stem marcescence, which not only may aid litter photodegradation and nutrient recycling but also deter herbivory and promote seed dispersal (tumbleweed). Conversely, slow‐growing alpine and subnival plants with higher water‐use efficiency, foliar C:N ratios and parenchymatic storage tissue rich in mobile carbohydrates had a high proportion of marcescent leaves, which may aid survival in these resource‐limited environments by providing delayed nutrients through moisture‐conserving mulch that also provides insulation and protection from frost. This study provides new insights into the complex interplay of habitat, seasonality and plant traits in dead phytomass retention in Himalayan plants. Marcescence is prevalent in resource‐conservative species in highly seasonal, resource‐limited habitats and may significantly shape the functioning and biodiversity of Himalayan ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Taxonomic classification of Praeclarispora herbicola comb. nov. in Leptosphaeriaceae (Pleosporales)

During our ongoing study of ascomycetes in Yunnan Province of China, a saprobic fungus was collected on a dead stem of Bidens pilosa (black-jack) in Yunnan Province, China. Preliminary identification based on the LSU, SSU, and ITS nucleotide BLAST searches demonstrated that the new isolate is related to Praeclarispora artemisiae and Phragmogibbera herbicola. Praeclarispora artemisiae and Ph. herbicola are morphologically resembled in having erumpent to superficial, subglobose, ostiolate ascomata, composed of thick-walled, carbonaceous or coriaceous, scleroplectenchymatous celled peridium, 8-spored, bitunicate, narrowly obovoid to cylindric-clavate asci and fusiform, versicolor, septate, thin- and smooth-walled ascospores. Phylogenetic analyses of the combined LSU, SSU, and ITS sequence dataset revealed that the new isolate shared the same branch length with Ph. herbicola but clustered with Pr. artemisiae in Leptosphaeriaceae. Hence, Ph. herbicola is transferred to Praeclarispora, and the new combination, Praeclarispora herbicola comb. nov. is introduced herein. The new isolate shows to be conspecific with Pr. herbicola based on morphological characteristics and is also supported by phylogenetic evidence. Therefore, our new isolate is identified as Pr. herbicola which is reported on Bidens pilosa for the first time.

DNA double-strand breaks enhance brassinosteroid signaling to activate quiescent center cell division in Arabidopsis.

In Arabidopsis roots, the quiescent center (QC), a group of slowly dividing cells located at the center of the stem cell niche, functions as an organizing center to maintain the stemness of neighboring cells. Recent studies have shown that they also act as a reservoir for backup cells, which replenish DNA-damaged stem cells by activating cell division. The latter function is essential for maintaining stem cells under stressful conditions, thereby guaranteeing post-embryonic root development in fluctuating environments. In this study, we show that one of the brassinosteroid receptors in Arabidopsis, BRASSINOSTEROID INSENSITIVE1-LIKE3 (BRL3), plays a major role in activating QC division in response to DNA double-strand breaks. SUPPRESSOR OF GAMMA RESPONSE 1, a master transcription factor governing DNA damage response, directly induces BRL3. DNA damage-induced QC division was completely suppressed in brl3 mutants, whereas QC-specific overexpression of BRL3 activated QC division. Our data also showed that BRL3 is required to induce the AP2-type transcription factor ETHYLENE RESPONSE FACTOR 115, which triggers regenerative cell division. We propose that BRL3-dependent brassinosteroid signaling plays a unique role in activating QC division and replenishing dead stem cells, thereby enabling roots to restart growing after recovery from genotoxic stress.

An easy, convenient statistical method to analyze bark beetle populations

A non-invasive method to estimate the number of Trypodendron lineatum holes on dead standing pines (Pinus sylvestris L.) was developed using linear and nonlinear estimations. A classical linear regression model was first used to analyze the relationship between the number of holes caused by T. lineatum on selected stem units and the total number of holes on an entire dead stem of P. sylvestris. Then, to obtain a better fit of the regression function to the data for the stem unit selected in the first step, piecewise linear regression (PLR) was used. Last, in an area used to evaluate wood decomposition (method validation), the total and mean numbers of T. lineatum holes were estimated for single dead trees and for a sample (n = 8 dead trees). Data were collected in 2009 (data set D1), in 2010–2014 (data set D2) and in 2020 (data set D3) in forests containing P. sylvestris located within Suchedniów–Oblęgorek Landscape Park, Poland. A model was constructed with three linear equations. An evaluation of model accuracy showed that it was highly effective regardless of the density of T. lineatum holes and sample size. The method enables the evaluation of the biological role of this species in the decomposition of dead standing wood of P. sylvestris in strictly protected areas.

Neomassaria khayae sp. nov., a novel pleosporalean species on Khaya senegalensis from Guangdong Province, China

Khaya senegalensis is a tropical plant native to Africa and grown as an ornamental plant in Southern China. During our sample collection in Guangdong Province, China, a saprobic Dothideomycetes was collected from a dead stem of K. senegalensis. The collection was identified as a neomassaria-like species based on the morphology. For further identification of the species, multigene phylogenetic analyses were conducted using large subunit nrDNA (LSU), small subunit nrDNA (SSU), RNA polymerase II second largest subunit gene (rpb2) and translation elongation factor 1-alpha (tef1-α). Based on morphology and phylogeny we identified our collection as a new species and introduced it as Neomassaria khayae. Morphologically, N. khayae distinguishes from other closely related species in terms of larger ascomata, asci and ascospore. In addition, this is the first report of Neomassaria species on K. senegalensis in China. This study will add to the biodiversity of saprobic fungi associated with Meliaceae hosts in Southern China.

Neocamarosporium aquaticum (Neocamarosporiaceae, Dothideomycetes), a novel fungus from salt marsh habitats

Abstract Neocamarosporium aquaticum, collected from a drift dead stem of a halophyte at the Kench Nature Reserve, Hayling Island, UK, is described as a new species in the family Neocamarosporiaceae, Dothideomycetes. Multi-locus analyses based on LSU, SSU, ITS rDNA, and EF1-α placed the new fungus as a distinct species in the genus Neocamarosporium, a sister to Neocamarosporium aesturinum isolated from seawater. The new species is characterized by the asexual morph with pycnidial conidiomata, doliiform, enteroblastic, annellidic conidiogenous cells, and conidia that are initially hyaline, aseptate, with longitudinal and transverse septa when matured, muriform, and turning brown to dark brown on maturity. Neocamarosporium aquaticum and Ne. aesturinum differ in the colour of the conidia, degree of septation, and conidial measurements.

Long‐term spatially‐replicated data show no physical cost to a benefactor species in a facilitative plant–plant interaction

Facilitation is an interaction where one species (the benefactor) positively impacts another (the beneficiary). However, the reciprocal effects of beneficiaries on their benefactors are typically only documented using short‐term datasets. We use Azorella selago, a cushion plant species and benefactor, and a co‐occurring grass species, Agrostis magellanica, on sub‐Antarctic Marion Island, comparing cushion plants and the grasses growing on them over a 13‐year period using a correlative approach. We additionally compare the feedback effect of A. magellanica on A. selago identified using our long‐term dataset with data collected from a single time period. We hypothesized that A. selago size and vitality would be negatively affected by A. magellanica cover and that the effect of A. magellanica on A. selago would become more negative with increasing beneficiary cover and abiotic‐severity, due to, e.g. more intense competition for resources. We additionally hypothesized that A. magellanica cover would increase more on cushion plants with greater dead stem cover, since dead stems do not inhibit grass colonization or growth. The relationship between A. magellanica cover and A. selago size and vitality was not significant in the long‐term dataset, and the feedback effect of A. magellanica on A. selago did not vary significantly with altitude or aspect; however, data from a single time period did not consistently identify this same lack of correlation. Moreover, A. selago dead stem cover was not significantly related to an increase in A. magellanica cover over the long term; however, we observed contrasting results from short‐term datasets. Long‐term datasets may, therefore, be more robust (and practical) for assessing beneficiary feedback effects than conventional approaches, particularly when benefactors are slow‐growing. For the first time using a long‐term dataset, we show a lack of physical cost to a benefactor species in a facilitative interaction, in contrast to the majority of short‐term studies.

Neofusicoccum vaccinii: A Novel Species Causing Stem Blight and Dieback of Blueberries in China.

Blueberries (Vaccinium spp.) have been considered to be a superfood because of their health benefits. Stem blight or dieback of blueberry has been frequently observed in commercial plantations, with incidences between 15 and 30% being observed in China. The causal agents of blueberry stem blight and dieback were surveyed at four commercial blueberry plantations in the Shandong, Fujian, Guizhou, and Yunnan Provinces of China during 2017 and 2019. Twenty-eight isolates of Neofusicoccum were obtained from 75 diseased and dead stem samples. Two taxa were identified. Of these, one novel species, Neofusicoccum vaccinii, was identified based on morphological characteristics and DNA sequence analysis of the concatenated internal transcribed spacer, the translation elongation factor-1α gene, and the beta-tubulin gene. Koch's postulates tests indicated that N. vaccinii was pathogenic toward blueberry. N. parvum is the other species isolated in this study. The optimal temperature for mycelial growth was 30°C for both N. vaccinii and N. parvum. N. vaccinii, however, was more virulent than N. parvum in this study at temperatures ranging from 25 to 30°C. Coinoculation of N. vaccinii and N. parvum did not lead to increased disease severity. On the contrary, the aggressiveness of N. vaccinii was suppressed by the presence of N. parvum at 25 to 35°C.

How does the condition of the pasture in late winter influence the plant and animal responses in the subsequent seasons?

This study aimed to test the hypotheses: (i) the deferred pasture with lower height in late winter has greater herbage accumulation rate (HAR) and better structure, which facilitates the animal selective grazing during the subsequent spring and summer; (ii) the mowed of high pasture in late winter improves the sward structure but decreases its HAR from the spring. Four pasture condition in late winter of Urochloa brizantha cv. Marandu were evaluated: low (24.1 cm and 2,420 kg.ha-1 of DM); low/mowed (25.2 cm and 2,198 kg.ha-1 of DM, mowed at 8.0 cm); high (49.0 cm and 3,837 kg.ha-1 of DM); and high/mowed (50.0 cm and 4,211 kg.ha-1 DM, mowed at 8.0 cm). The highest live leaf blade percentage (LLBP) and the lowest dead stem percentage (DSP) occurred in the mowed pastures. The live stem (LSP) and dead leaf blade percentages of the grazing simulation sample were higher in the high pasture. This same pattern of response occurred for apparent selectivity indices (ASI) of the live leaf blade and live stem. The ASI of the dead leaf blade was greater in the high pasture, intermediate in the mowed pastures, and lower in the low pasture. The ASI of the dead stem was lower in the low pasture. The HAR was higher in low pasture. Our results support the first hypothesis. The mowing of high pasture in late winter improves the sward structure and the animal selective grazing but does not decrease the HAR during spring and summer.

Does amount of cut vegetal residue on the canopy influence growth and the structural characteristics of marandu palisadegrass?

The pasture mowing in late winter removes the old forage, improving the pasture structure in spring and summer. However, the residue after mowing can affect tillering, thus limiting forage production and the structural characteristics of pasture. We hypothesized that the high amount of cut vegetal residues on the plants in late winter causes a decrease in forage production and modifies the structural characteristics of the forage canopy during the spring and summer. The treatments were four cut vegetal residues (0; 2,000; 4,000 and 8,000 t ha-1 of natural material) deposited on Urochloa brizantha cv. Marandu canopy in late winter. After that, the forage production and structure characteristics were evaluated during the spring and summer for two years. The complete randomized block design, with four replications, was used. The defoliation management was characterized by the adoption of pre- and post-cut heights of 25 and 15 cm, respectively. For both years, there was no effect of cut vegetal residue on all the characteristics evaluated. No variable was affected by the interaction cut vegetal residue amount × year of evaluation. The dead leaf blade percentage was greater in year 2 (6.9%) than in year 1 (3.5%). The average values of variables were live leaf blade percentage = 84.2%; live stem percentage = 8.7%; dead stem percentage = 1.9%; number of vegetative tiller = 653 tiller/m2; number of reproductive tiller = 5 tiller m-2. The forage production rate presented an average value of 46 kg/ha/day of dry matter. The cut vegetal residue amount of up to 8,000 t/ha of natural material on the plants in late winter does not affect the forage production or modifies the structural characteristics of marandu palisadegrass during the subsequent spring and summer.

Distribution and harmfulness of Mordellistena parvuliformis Beetle in the left Bank Steppe of Ukraine

Harmfulness and spread of a new dangerous pest of Mordellistena parvuliformis Stshegol.-Bar, 1930 have been recorded in the north-east of Ukraine. The results of researches of the reasons of occurrence, harmfulness and distribution of this dangerous pest of sunflower are generalized.
 It was found that the larvae of the sunflower Mordellistena parvuliformis from the diapause occur from the end of the third decade of April after feeding on dead stem tissue. Depending on the time of hatching, the presence of pupae is observed until the end of May. From the third decade of May, you can see the flight of adults and after a short additional feeding on flowering vegetation — the beginning of mating. Adult flight lasts a little more than 1.5 months — until the second decade of July. Embryonic development lasts about two weeks. The last eggs laid were observed in early August. From the second decade of June there was a revival of larvae, which are in an active state inside the stems until mid-September until the end of feeding and transition to a state of rest for further wintering. Thus, the development of one complete generation of toadstools per year is established.

Molecular phylogeny and diversity of Laburnicola (Didymosphaeriaceae): a new species from Uzbekistan

Laburnicola is a genus in Didymosphaeriaceae that includes saprobic and endophytic fungal taxa. The current study conducted in the subalpine region of Uzbekistan discovered a new species on a dead stem of a wild rose plant. Maximum likelihood and Bayesian analyses of combined LSU, SSU, ITS, and TEF 1-ɑ dataset confirmed the new species’ taxonomic position in Laburnicola. Our new species, Laburnicola zaaminensis (TASM 6152), was clustered with L. dactylidis (MFLUCC 16-0285) with strong bootstrap support. A detailed description together with illustrations are provided for Laburnicola zaaminensis. Furthermore, an annotated species list, a distribution map, and a taxonomic key for Laburnicola species are provided. This is the first record of Laburnicola from Central Asia.

A Review Over the effect of Heavy Metal in Metabolism of Brassica juncea (L.) and Myristica fragrans

Brassica juncea (L.) and Myristica fragrans are common plants found in India where the concentration of heavy metals in water and soil is observed more frequently and in sufficient amounts to cause bad effects to the living entity. In plants various kinds of bad effects such as dwarfness, yellowish leaves, dead leaves, brownish and dead stem. These are kinds of symptoms that one can observe in plants suffering from the bad effects of heavy metal absorption. At a specific time, they should be identified and treated for the same otherwise this may cause an increase in dead material in the plant, day by day. This review summarizes the bad effects of heavy metals in plants like these two.

Biological Control Against Four-Stored Product Beetles Pests by Using Cytoplasmic Polyhedrosis Virus (Cypovirus1)

The rice weevils, tobacco beetle, drug beetle, and Darkling beetle were collected from different locations in Mecca regions, KSA. The four different larvae attack stored products cause economic losses by incredible damage and post-harvest. This investigation was Carrie out to identify characters these insects include. In addition, Cypovirus1 was isolated and collected from living and dead stem and cob borer larvae and pupae from Maize in farmers' fields at Mecca regions, KSA. Samples have ch

Hogweed Biomass as a Raw Material for Producing 2D Nanocarbons: An Environmental Aspect

The possibility of carbonization of the biomass of Sosnowski hogweed under the conditions of self-propagating high-temperature synthesis (SHS) was explored. It was found that carbonization of the hogweed biomass samples taken in the flowering and dead stem phases gave 30‒40% carbonized product. The yield of the carbonized product from the hogweed biomass sample taken in the early vegetative phase (before flowering) did not exceed 2%. Such a low yield may be due to the features of the formation of the nanocarbon precursor in the process of plant development. Analysis by several complementary techniques (Raman spectroscopy, X-ray diffraction) showed that, in terms of their morphometric parameters, the carbonized product particles correspond to 2D nanocarbon, specifically to graphene nanoplatelets.

Mowing and lowering the marandu palisadegrass sward height at late winter improve the sward structure

The structure of the sward is important because it influences the responses of plants and animals in grazing conditions. The objective with this work was to evaluate the structural characteristics of the Marandu palisade grass pasture (Brachiaria brizantha syn. Urochloa brizantha) during spring and summer, depending on the condition of the sward at the end of winter. Four grazing conditions at the end of winter were evaluated: short (24.1 cm), short (25.2 cm)/mown (8 cm), tall (49.0 cm) and tall (50.0 cm)/mown (8 cm). The foliar area index was lower in the tall pasture than in the tall/mown pasture. The mass and the volumetric density of dead stem were higher in the tall pasture, intermediate in the short pasture, and lower in mowed pastures. At the beginning of the grazing period, the live stem mass was higher in the tall pasture. At the beginning and middle of the grazing period, the volumetric density of dead leaf lamina was lower in mowed pastures. At the beginning of the pasture period, the short pasture had a higher tiller number (TN). In the middle of the grazing period, the short and short/mown pastures had higher TN. At the end of the pasture period, the lowest TN value occurred in the tall pasture. The tall pasture at the end of winter presents an unfavorable structure to the animal in grazing, while the mowing and reduction in the height of the marandu palisade grass improves the structure of the sward in spring and summer.

Initial height and nitrogen fertilisation on deferred pastures of marandu palisadegrass

In deferred pastures, nitrogen fertilisation and pasture height at the beginning of the deferment period modify the structure and nutritive value of forage. This work was conducted to determine the nitrogen (N) doses and sward heights that were adequate for the deferment of Brachiaria brizantha cv. Marandu syn. Urochloa brizantha cv. Marandu (marandu palisadegrass). Two sward heights (15 and 30 cm) and four N rates (0, 40, 80,120 kg/ha) at the beginning of the deferment period were evaluated in a randomised block design and a factorial scheme with three replications. At the end of the deferment period, the numbers of live and dead tillers, the numbers of tillers with different sizes, the masses of live leaf lamina, dead leaf lamina, live stem and dead stem, the litter mass and the crude protein and neutral detergent fibre contents of the forage were evaluated. With nitrogen fertilisation, there was an increase in the masses of live leaf and live stem in the deferred canopy. With the application of 80 kg/ha of N, the litter mass was higher in the deferred canopy with a height of 30 cm, in relation to that with a height of 15 cm. The highest canopy presented greater stem mass and worse nutritional value when compared to the lowest one. In order to improve forage characteristics, marandu palisadegrass can be deferred by 15 cm and fertilised with 80 kg/ha N. When marandu palisade grass is deferred to 30 cm, nitrogen doses lower than 80 kg/ha can be applied.

Apparent selectivity of sheep in deferred marandu palisadegrass pastures with variable initial heights

ABSTRACT The objective of this study was to evaluate the apparent selectivity of sheep in marandu palisadegrass (Urochloa brizantha cv. Marandu) pastures with four heights at the beginning of the deferment period (15, 25, 35 and 45cm). The deferment period was 92 days and started on 03/21/2014. Evaluations occurred in the beginning (first week), middle (45th day) and end (92nd day) of the grazing period, in winter (06/21/2014 to 09/21/2014). Deferred pastures with 15 and 25cm presented lower forage mass (FM), but higher live leaf (LL) percentage in FM than deferred pastures with 35 and 45cm. The live stem percentage in the FM and the apparent selectivity index (ASI) of the LL were superior in the deferred pasture with 45cm. The dead stem (DS) percentage in the grazing simulation (GS) and the ASI of this morphological component were lower in the pasture with 15cm, compared to the deferred pasture with 45cm. The FM and the LL percentages in FM and in the GS sample decreased, while the DS percentages in FM and in GS sample increased with the grazing period. Marandu palisadegrass with 15cm at beginning of the deferment period improves the morphology of the deferred pasture. Selective grazing is difficult during the grazing period.