Induction of hormesis in plants by urban trace metal pollution

Hormesis is a dose–response phenomenon observed in numerous living organisms, caused by low levels of a large number of stressors, among which metal ions. In cities, metal levels are usually below toxicity limits for most plant species, however, it is of primary importance to understand whether urban metal pollution can threaten plant survival, or, conversely, be beneficial by triggering hormesis. The effects of Cd, Cr and Pb urban concentrations were tested in hydroponics on three annual plants, Cardamine hirsuta L., Poa annua L. and Stellaria media (L.) Vill., commonly growing in cities. Results highlighted for the first time that average urban trace metal concentrations do not hinder plant growth but cause instead hormesis, leading to a considerable increase in plant performance (e.g., two to five-fold higher shoot biomass with Cd and Cr). The present findings, show that city habitats are more suitable for plants than previously assumed, and that what is generally considered to be detrimental to plants, such as trace metals, could instead be exactly the plus factor allowing urban plants to thrive.

Effect of Dust Deposition on Chlorophyll Concentration Estimation in Urban Plants from Reflectance and Vegetation Indexes

Using reflectance spectroscopy to monitor vegetation pigments is a crucial method to know the nutritional status, environmental stress, and phenological phase of vegetation. Defining cities as targeted areas and common greening plants as research objects, the pigment concentrations and dust deposition amounts of the urban plants were classified to explore the spectral difference, respectively. Furthermore, according to different dust deposition levels, this study compared and discussed the prediction models of chlorophyll concentration by correlation analysis and linear regression analysis. The results showed: (1) Dust deposition had interference effects on pigment concentration, leaf reflectance, and their correlations. Dust was an essential factor that must be considered. (2) The influence of dust deposition on chlorophyll—a concentration estimation was related to the selected vegetation indexes. Different modeling indicators had different sensitivity to dust. The SR705 and CIrededge vegetation indexes based on the red edge band were more suitable for establishing chlorophyll-a prediction models. (3) The leaf chlorophyll concentration prediction can be achieved by using reflectance spectroscopy data. The effect of the chlorophyll estimation model under the levels of “Medium dust” and “Heavy dust” was worse than that of “Less dust”, which meant the accumulation of dust had interference to the estimation of chlorophyll concentration. The quantitative analysis of vegetation spectrum by reflectance spectroscopy shows excellent advantages in the research and application of vegetation remote sensing, which provides an important theoretical basis and technical support for the practical application of plant chlorophyll content prediction.

Dynamics of the content of ascorbic acid and catalase activity in leaves of three plant species in urban and natural environments during the vegetation period of plants

In this study, we collected the leaves of three plant species, Larix sibirica, Rosa acieularus and Plantago major, during the vegetation period, growing in the same place in urban and urban forest environments. A comparative assessment of antioxidant enzyme catalase activity and content of ascorbic acid in the leaves of these plants was carried out. The results showed that the content of ascorbic acid is higher in Larix sibirica compared to Rosa acieularus (3.56 and 3 times higher) and Plantago major (15.35 and 9.76 times higher), both in urban and forest plants. In urban plants, the catalase activity was higher in Plantago major compared to Larix sibirica (7.95 times) and Rosa acieularus (1.04 times); and in forest plants the catalase activity was higher in Rosa acieularus compared to Plantago major (1.1 times) and Larix sibirica (4.13 times). In urban plants, the content of ascorbic acid was by 5.8-50% lower, and the catalase activity was by 28.9-65.7% lower than in forest plants, which indicates that the studied plants are more susceptible in urban environment. Catalase activity and ascorbic acid contents showed an inverse relationship. Depending on the plant species, the components of the enzymatic and non-enzymatic antioxidant systems are involved in different ways in the binding of free radicals formed in plants in response to stress. Хот болон хот орчмын ногоон бүсэд ургасан гурван зүйл ургамлын вегетацийн үеийн витамин С-ийн агууламж, каталазын идэвхийн динамик Энэхүү судалгаанд нэг орчинд ургах гурван зүйл ургамал болох Сибирь шинэс (Larix sibirica Ledb.), Өргөст нохойн хошуу (Rosa acieularus Linde.), Их таван салаа (Plantago major L.) ургамлын навчны дээжийг Улаанбаатар хот болон хот орчмын ногоон бүсээс вегетацийн хугацаанд нь цуглуулан орчиндоо дасан зохицох үйл явцад оролцох исэлдэн-ангижрах фермент болох каталазын идэвх, хүчтэй антиоксидант нэгдэл болох витамин С-ийн агууламжийн тодорхойлон харьцуулав. Судалгааны ажлын үр дүнгээр Улаанбаатар хот болон хот орчмын ногоон бүсийн ургамлуудаас Сибирь шинэс витамин С-ийн агууламжаар Өргөст нохойн хошуу (3.56 болон 3 дахин), Их таван салаа (15.35 болон 9.76 дахин)-аас өндөр байв. Их таван салаа Улаанбаатар хотын орчинд ургасан ургамлуудаас каталазын идэвхээр Сибирь шинэс (7.95 дахин), Өргөст нохойн хошуу (1.04 дахин)-аас өндөр байсан бол хот орчмын ногоон бүсийн ургамлуудын хувьд Өргөст нохойн хошуу Их таван салаа (1.1 дахин), Сибирь шинэс (4.13 дахин)-ээс каталазын идэвхээр өндөр байв. Хот орчмын ногоон бүсэд ургасан ургамлуудтай харьцуулахад Улаанбаатар хотын ургамлуудад витамин С-ийн агууламж 5.8-50%-иар каталазын идэвх 28.9-65.7%-иар буурсан ерөнхий зүй тогтол илэрсэн нь Улаанбаатар хотын орчинд ургаж буй ургамлууд стресст илүү өрсөн байгааг гэрчлэнэ. Судалсан ургамлуудын хувьд тухайн ургамлын зүйлээс хамаарч хүрээлэн буй орчны тааламжгүй нөхцлийн хариуд үүсэх ROS-ийн нэгдлүүдийг саармагжуулахад ферментийн болон ферментийн бус системийн бүрэлдэхүүнд орох нэгдлүүд ялгаатай оролцож байхаас гадна каталазын идэвх, витамин С-ийн агууламжтай эсрэг хамааралтай байгааг бидний судалгаа харууллаа. Түлхүүр үг: Ургамал, навч, стресс, витамин С, каталаза

urban vegetation of algiers : urban ecology approach

<p>In the 21st century, where problems related to the city are legion (climate change, disease, depression, crime, etc.), urban ecology promises to provide concrete and effective solutions to enable humanity to live and the planet to breathe.</p><p>In a southern metropolis such as Algiers, these seemingly endless urban problems are becoming more acute due to a galloping population and an unbridled expansion of the urban fabric. This expansion is often at the expense of green spaces.</p><p>In this way, we worked on methodologies that will enable us to quantify the layout, condition and influence of these green spaces and to develop more appropriate management plans to optimize there functions.</p><p>We also carried out a preliminary study for the landscape analysis and spatialization of urban plants, to be able to deepen the study later and create an interrogative spatial database to help decision-making.</p>

Study on Diversity and Protection Countermeasures of Zhongshan Park in Wuhan City

Park green space is an important part of garden green space, concentrated expression of the diversity of urban plants. In order to explore the diversity of plants in the park, a typical site in Zhongshan Park in Wuhan was selected for this survey. The species importance, richness index, diversity index and evenness index were used to analyze the characteristics of plant diversity.There are a total of 184 plants of 114 genera and 64 families in Wuhan Zhongshan Park. Among them, there are 86 species of plants of 40 families and 64 genera, 60 species of plants of 26 families and 38 genera, and 26 species of herbs, 11 families and 15 genera.The richness was herb layer > tree layer > shrub layer.Pielou uniformity was herb layer > tree layer > shrub layer;Shannon-wiener diversity was herb layer > tree layer > shrub layer.Simpson diversity was herb layer > tree layer > shrub layer.The diversity of herbaceous plants in the park is high, and the index of shrub layer is generally low, with few species. Plants in the park grow well, some plants are not evenly distributed.

The ecology of urban system: assessment using Spiraea plants

The article presents the results of the study of the shift in the morphological parameters of the leaves of three species of the genus Spiraea L. growing under the conditions of transport-caused and industrial pollution in large industrial citi of Western Siberia (Novosibirsk) in comparison with that in background conditions (reference). The morphological indices (length, width, perimeter, and area of the lamina) were determined by digital image analysis using the Maplnfo software. The anthropogenic impacts induced a reduction in the size of the assimilating organs and an increase in the index of the fluctuating asymmetry of the leaves of urban plants compared to background plants. According to the fluctuating asymmetry index, the environmental quality of the Lenin district of Novosibirsk was assessed as critical, meanwhile that of the reference conditions corresponded to the norm.