scholarly journals Drought-induced mortality: stem diameter variation reveals a point of no return in lavender species

2019 ◽  
Author(s):  
Lia Lamacque ◽  
Guillaume Charrier ◽  
Fernanda dos Santos Farnese ◽  
Benjamin Lemaire ◽  
Thierry Améglio ◽  
...  

AbstractIn the context of climate changes, water availability is expected to severely decline. Consequently, there is a need to predict mortality of woody species, especially to find a physiological threshold to drought-induced mortality. Lavender species (Lavandula angustifolia and Lavandula x intermedia) which are important crops of the Mediterranean region are affected by a decline, notably caused by successive intense drought events. Lavender response to extreme drought events was monitored using continuous stem diameter measurements. Water potential, stomatal conductance, loss of xylem hydraulic conductivity and electrolyte leakage were also measured during desiccation, and recovery was evaluated after rewatering. Two parameters computed from stem diameter variations were related to stress intensity and resilience to stress: PLD (Percentage Loss of Diameter) and stem PLRC (Percentage Loss of Rehydration Capacity of the stem), respectively. We showed that plants did not recover when the PLD reached its maximal value (PLDmax) which was 21.27 ± 0.57% in both lavender species and whatever the growing conditions. This point of no return was associated with a high level of cell lysis evaluated by electrolyte leakage, and occurred far after the xylem hydraulic failure. We discussed the relevance of PLDmax as a threshold for drought-induced mortality and its physiological significance, in relation to the mortality mechanisms.One-sentence summaryUnder extreme drought, lavender death occurs when the water storage of the elastic compartment of the stem is exhausted.

Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.


Author(s):  
Matiashuk R. ◽  
Tkachenko I.

The sensitivity of the reproductive structures of Forsythiasuspensato the complex influence of undifferentiated environmental factors has been studied.The monitoring sites are located in 15 different park ecosystems in 6 administrative districts of Kyiv. Data from the Borys Sreznevsky Central Geophysical Observatory (air pollution index (API) and meteorological conditions for 2018-2020) were used to assess the conditions of the growthenvironment. The influence of a complex of ecologically important factors during the flowering offorsythia on the quality of the formedpollen is noted. Thus, growing plantsfor a long time in conditions with a low level of air pollution (APIup to 5.0) in abnormal weather conditions in 2020,40-50% less fertile grainswere formed. And forplants, which grow in areas with increasedlevel (API5.0-7.0) and high level (API7.0-14.0) of air pollution, the share of fertile grains in the pollen population decreased by 60-80%. In the closed bud,the pollen has higher resistance to a complex of exogenous growth factors. Forsythia plants, which are located in large parklands, lose less pollen quality in adverse weather conditions and affected byurbotechnogenic factors. F. suspensa is an acceptable indicator of the level of environmental pollution by the deviation of pollen fertility from the control value. In areas with high aerogenic load, for example, areas with large highways (Bus Station «Darnytsia»), as well as with a significant recreational load (HolosiivskyiPark, Recreation Park on the Olena Teliha Street) much smaller pollen is formed. Itis noted that the conditions of forsythia growth affect the quantitative indicators of the formed pollen not only in the flower but also in the closed bud, which confirms the chronic effect of the complex of ingredients of aerotechnogenic emissions on plants of this species. The coefficient of sterility of pollen (CS) was used to objectively compare the data of 2019 and 2020 on the condition of the generative organs of F. suspensa in the studied areas. The calculation of the CS confirmed that in the closedbud pollen has a higher resistance to exogenous factors. In areas with high and increased levels of air pollution,during budding and flowering of plants (March-May,) there is a much higher CS of pollen of F. suspensа. Significant parkland territoriesof the city (for example, HolosiivskyiPark, Botanical Garden named after O. V. Fomin) provide less stressful conditions for growth and development of plants, even with the "very high" level of air pollution (ISA above 14.0) observed in April 2020 on this territory.The study of the susceptibility of F. suspensаpollen to growing conditions will be continued, as the prospects of using this species for bioindication of ecological status and zoning of park ecosystems of Kyiv according to the gradient of anthropogenic impact have been revealed.Key words:forsythia, fertility, coefficient of sterility of pollen, bioindication. Проведене дослідження чутливості репродуктивних структур Forsythiasuspensaдо комплексного впливу недиференційованих факторів навколишнього середовища. Моніторингові ділянки розташовані в 15 різних паркових екосистемах 6 адміністративних районівКиєва. Для оцінки умов середовища вирощування рослин використані дані Центральної геофізичної обсерваторії імені Бориса Срезневського (індекс забруднення атмосферного повітря (ІЗА) та метеорологічні умови за 2018-2020 рр.). Відмічено вплив комплексу екологічно важливих факторів (за показниками відхилення від норми середньої місячної температури повітря та місячної кількості опадів у Києві) уперіод квітування форзиції на якість сформованого пилку. Так, за тривалої експозиції рослин в умовах з низьким рівнем забруднення повітря (ІЗА до 5,0) в аномальних погодних умовах 2020 р. сформувалось на 40-50% менше фертильних зерен. А у форзиції, яка росте на територіях з підвищеним (ІЗА 5,0-7,0) та високим (ІЗА 7,0-14,0) рівнями забруднення частка фертильних зерен в популяції пилку зменшилась на 60-80%. У закритому бутоні пилок має вищу стійкість до комплексу екзогенних факторів середовища зростання. Рослини форзиції, які розташовані у значних за площею паркових насадженнях, менше втрачають якість пилку за несприятливих погодних умов та дії урботехногенних чинників. За відхиленням показника фертильності пилку від контрольного значення F. suspensaє допустимим індикатором рівня забруднення середовища. На територіях з підвищеним аерогенним навантаженням, наприклад, ділянки з автотранспортними магістралями (Автостанція «Дарниця»), а також зі значним рекреаційним навантаженням (Голосіївський парк імені М. Рильського, Парк відпочинку по вул. Олени Теліги)формується значно дрібніший пилок. Відмічено, що умови росту позначаються на кількісних показниках сформованого пилку не лише в квітці, але й в закритому бутоні, що підтверджує хронічний вплив комплексу інгредієнтів аеротехногенних викидів нарослини цього виду. Для об’єктивного співставлення даних 2019 і 2020 рр. щодо стану генеративних органів F. suspensaна досліджених ділянках був використаний коефіцієнт стерильності (КС) пилку. Розрахунок КС підтвердив, що в закритому бутоні пилок має вищу стійкість до впливу екзогенних чинників. Вищий КС був у F. suspense, з ділянок, на яких в період бутонізації і квітування рослин (березень-травень) відмічений високий і підвищений рівень забруднення атмосфери. Значні за площею паркові насадження міста (наприклад, Голосіївський парк, Ботанічний сад ім.акад. О.В. Фоміна) забезпечують менш напружені умови росту і розвитку рослин навіть при відміченому в квітні 2020 р. «дуже високому» рівні забруднення повітря (ІЗА вище 14,0) на цих територіях. Дослідження чутливості пилку F. suspenseдо умов вирощування буде продовжене,оскільки виявлена перспективність використання цього виду для біоіндикації екологічного стану та зонування паркових екосистем Києва за градієнтом антропогенного впливу.Ключові слова: форзиція, фертильність, індекс стерильності, біоіндикація.


Author(s):  
Rina Arimarsetiowati ◽  
Fitria Ardiyani

Plantlet that has developed shoots and roots will have a high level adaptation in the field. The objective of this experiment was to improve the ability of planlet in shooting and rooting so that it is ready for acclimatization in the field. The increase ability in shooting and rooting of the planlet were conducted by adding various types of auxin in the media. The arabica coffee embryo of clone AS 2K which has entered the phase of the cotyledons was transfered into the treatment media containing half-strength of MS (Murashige & Skoog) macro and micro nutrient, vitamin B5, 30 g/L glucose, 100 ml/L coconut water, 50 mg/L AgNO3 added with the combination of IAA, IBA and NAA. The research was conducted by using completely randomized design with seven combined treatment i.e. 0.1 mg/L IBA, 0.1 mg/L NAA, 0.1 mg/L IAA; 0 , 1 mg/L IBA + 0.1 mg/L NAA, 0.1 mg/L IBA + 0.1 mg/L IAA, 0.1 mg/L NAA + 0.1 mg/L IAA; without auxin. There were 12 replications in every treatment and each replication consisted of five cotyledonary embryos. The parameters of observation were the root length, leaf number, leaf area, stem diameter, and height of plantlets. The observations were conducted in eighth weeks after cotyledonary embryo had shoots. The results showed that in the number of leaves and height of planlet parameters, the treatment without auxin was the best result compared to planlet with auxin addition. The addition of auxin varians and their combination did not significantly influent leaf area, root length and stem diameter parameters. The medium tested was optimum for the growth of shoots and roots of AS 2K arabica coffee.


2021 ◽  
pp. 219-225
Author(s):  
Галина Табаленкова

The results of studies of the qualitative composition and quantitative content of amino acids (AAs) in the leaves of three plant species of the genus Artemisia, widespread in the Elton region, were presented. Protein AAs were determined on an AAA T-339 amino acid analyzer (Czech Republic) after hydrolysis of a sample in 6N HCl at 105 °C for 24 h, free AAs – on an AAA-400 amino acid analyzer (Czech Republic) in a lithium buffer system. The protein AAs amount varied from 66 mg / g in A. lerchiana to 113 mg / g dry weight in A. santonica. 17 AAs were found in composition of these species, aspartic and glutamic acids were dominant. The content of free AAs varied from 4.4 mg / g in A. santonica to 8.3 mg / g dry weight in A. pauciflora. 14 AAs have been identified, among them proline was the predominant free AA. The share of proline was 75-81% of the total free AAs. Among the minor components, 3-4 compounds with a content above 2% dominated. The free AAs contain 3 non-proteinogenic ones (ornithine, citruline, and γ-aminobutyric acid). A. lerchiana and A. pauciflora species were similar in protein and free amino acids, probably due to the same growing conditions. A high level of free proline, together with a complex of biologically active substances in Artemisia species, which grow abundantly in the Elton region, allow to consider the possibility of their use as a medicinal raw material.


2019 ◽  
Vol 223 (4) ◽  
pp. 1834-1843 ◽  
Author(s):  
William M. Hammond ◽  
Kailiang Yu ◽  
Luke A. Wilson ◽  
Rodney E. Will ◽  
William R. L. Anderegg ◽  
...  

1991 ◽  
Vol 21 (6) ◽  
pp. 821-828 ◽  
Author(s):  
Robert G. Wagner ◽  
Steven R. Radosevich

Neighborhood models describing the effect of interspecific competition on the height and stem diameter of 4- to 9-year-old saplings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were developed from site-preparation experiments in the Oregon Coast Range. The influence of abundance measures, height, distance, arid spatial arrangement of nonconiferous woody plants surrounding individual saplings was examined. Optimum neighborhood heights and radii were defined. The best interspecific competition index for predicting Douglas-fir height and stem diameter was total percent cover for all woody species within a 2.1-m radius. Visual estimates of neighbor cover were superior to objective measures of crown area. The cover of woody species equalling or exceeding the height of the tree provided the best prediction for tree height. Woody species cover equalling or exceeding one-half the height of the tree provided the best index for predicting stem diameter. Accounting for the spatial arrangement of neighboring woody plants did not improve the competition index. Interaction between the competition index and tree age indicated that the negative effect of interspecific competition on Douglas-fir size increased with time. The age-adjusted competition index accounted for 11% of the variation in height and 19% of the variation in stem diameter. Douglas-fir stem diameter was more sensitive to neighboring woody plants than was height.


2004 ◽  
Vol 52 (4) ◽  
pp. 509 ◽  
Author(s):  
Kate McClenahan ◽  
Catriona Macinnis-Ng ◽  
Derek Eamus

Seasonal comparisons of leaf water potential, root biomass, hydraulic architecture, xylem embolism and xylem dimensions were made for eight woody species in four diverse habitats (mangroves, coastal heathland, ridge-top woodland and river-flat woodland). In most comparisons, pre-dawn and minimum leaf water potentials were lower in winter than in summer, a result attributed to lower rainfall and a smaller root biomass in winter than in summer. Branch hydraulic conductivities (per unit transverse area, sapwood area or leaf area) were generally larger in summer than in winter across all species in all habitats. An inverse relationship between Huber value and conductivity was observed across all four habitats. Increased solar radiation and evaporative demand in the summer was associated with an increased percentage loss of xylem conductance arising from embolism, compared with winter. These results are discussed in the context of patterns and relationships among water relations, microclimate and hydraulic architecture.


Agronomy ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 84
Author(s):  
Rong Zhou ◽  
Benjian Cen ◽  
Fangling Jiang ◽  
Mintao Sun ◽  
Junqin Wen ◽  
...  

Salt stress is one of the primary abiotic stresses that negatively affects agricultural production. Melatonin, as a useful hormone in plants, has been shown to play positive roles in crop improvement to abiotic stress conditions. However, it remains unclear whether spraying melatonin could reduce the halotolerance gap between tomato genotypes with different salt sensitivities. Here, plant growth, H2O2 content, electrolyte leakage, antioxidant system, gas exchange, pigment content, and chloroplast ultrastructure of salt sensitive genotype (SG) and resistant genotype (RG) at CK (control), M (spraying melatonin), S (salt), and SM (spraying melatonin under salt stress) were investigated. The results showed that the weight, height, and stem diameter of the plant at SM from both genotypes significantly increased compared with S. The plant undergoing SM from both genotypes showed significantly decreased H2O2 but increased activity of SOD, APX, GR, and GSH, as well as net photosynthetic rate and Fv/Fm, as compared with S. The ratio between SM and S (SM/S) of SG was significantly higher than that of RG in terms of plant height and stem diameter, whereas antioxidant parameters, H2O2 content, and electrolyte leakage showed no difference between RG and SG in SM/S. The SM/S of SG in terms of photosynthetic parameters and pigment content were significantly higher than that of RG. Chloroplast ultrastructure showed remarkable changes under salt stress, whereas spraying melatonin reduced the destruction of chloroplasts, especially for SG. We concluded that spraying melatonin reduces the halotolerance gap between SG and RG by photosynthesis regulation instead of the antioxidant mechanism. This indicated that the positive roles of melatonin on tomato plants at salt stress depend on the genotype sensitivity.


2019 ◽  
Vol 4 (2) ◽  
pp. 103-110
Author(s):  
Ryan Rifqi Arista ◽  
Rosa Andrie Asmara ◽  
Dwi Puspitasari

The Indonesian region has a high level of earthquake vulnerability when compared to other countries. This is because Indonesia's position is at the confluence of three large tectonic plates namely the Eurasian plate, the Indo-Australian plate, and the Pacific plate. The high level of earthquake susceptibility is evidenced by significant earthquake data from 2005 to 2009, which recorded 26 significant earthquakes over a period of 4.8 to 8.6 on the Richter scale. The earthquake also caused impacts including casualties, injuries, damage to houses and destruction of houses.The earthquake event grouping system is a system that functions to classify earthquake events based on two main parameters, namely earthquake strength parameters and earthquake impact parameters. The two parameters are grouped separately, so that the grouping process produces two kinds of grouping results. The stages of this system start from preprocessing data to eliminate noise, then take grouping parameters from the user in the form of the number of clusters, minimum error values, and the maximum iteration limit. Grouping is done using fuzzy c-means method. The grouping results are then displayed in table form and in the form of coordinates in Google Maps.The grouping of earthquake events has been tested by comparing the results of grouping systems with the results of manual grouping. Testing is done by inputting a number of different maximum iterations. Based on the test results it was found that the greater the maximum iteration value will affect the accuracy of grouping.


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