Leaf surface index as an indicator of moisture responsiveness and drought resistance of winter bread wheat samples

The growth and productivity of drought-prone varieties are strongly influenced by the chlorophyll pigment content and the development of plants’ foliage. The current climate changing, characterized by long no-rain periods followed by short intense rainfalls, is forcing plants to adopt different strategies to cope with drought. The purpose of the current study is to estimate the effect of growing conditions on the indicators of the total leaf area, leaf surface index (LSI) of sowing, the concentration of chlorophylls (Chl) in the leaves and the yield of winter wheat, depending on the value of their moisture supply. There have been established that the leaf surface index change and the preservation of chlorophyll pigment in foliage during the vegetation period is closely related to plants’ drought resistance, soil moisture reserve and a genotype. Under conditions of insufficient moisture supply, the maximum values of the leaf surface index in the heading phase were formed by the varieties ‘Krasa Dona’ (5.99 r.u) and ‘Etyud’ (2.49 r.u.). The highest content of chlorophyll pigment, both in the heading phase and in the flowering phase, was identified in the varieties ‘Krasa Dona’ (3.7; 3.0 mg/100 g of raw material), ‘Etyud’ (3.4; 3.2 mg/100 g of raw material) and ‘Volny Don’ (3.2; 3.0 mg/100 g of raw material), respectively. Acording to the value of productivity, the reliably standard variety ‘Don 107’ has exceeded the varieties ‘Etyud’, ‘Krasa Dona’, ‘Asket’, ‘Volny Don’.

Chlorophyll pigment and needle macronutrient responses and interactions to soil moisture and atmospheric CO2 treatments of eight pine and spruce species

Key message Large differences were detected between genera and among species in chlorophyll pigment and macronutrient concentrations. Pines have greater variances than spruces and showed less downregulation of chlorophyll pigment concentrations than spruces in response to eCO2 and DRT. There was strong genetic control of chlorophyll pigments and most macronutrients. Abstract Chlorophyll pigment and needle macronutrient concentrations were quantified for eight tree species in two commercially important genera, Pinus and Picea grown in a 2 × 2 factorial of atmospheric CO2 (370 and 740 ppm) and soil moisture stress (− 0.1 to − 0.5 and − 0.7 to − 1.0 MPa) treatments. Four of the pines and three of the spruces are native to eastern North America, while a fourth spruce, Norway spruce (NS: Picea abies), is from Europe but has been widely used for reforestation in northeastern North America. Overall, spruces had significantly greater chlorophyll a, b, (CHLa, CHLb), and total chlorophyll concentration (TCC) and carotenoid concentration (CAR) than pines. Ambient CO2 (aCO2) had significantly greater TCC than in response to elevated CO2 (eCO2), and TCC and CAR was significantly downregulated more in spruces than in pines in response to eCO2. Pines had equal or greater TCC and CAR in response to drought treatment (DRT) than well-watered treatment, whereas spruces had significantly lower values in response to DRT. Needle N, P and Ca concentrations were greater for spruces than pines. Needle N concentrations declined in response to both eCO2 and DRT. Needle P increased in response to eCO2 but declined in response to DRT. Using total biomass as a covariate, needle N showed no response in pines; whereas spruces showed a slight positive response to increasing total biomass. Covariate analysis showed that TCC had a significant positive relationship to needle N and Mg, with greater TCC in spruces than in pines for a given needle N. Photosynthetic quantum efficiency (QE), derived from light response curves, had a significant positive relationship to TCC that was greater in pines than in spruces for a given TCC. Photosynthetic light convexity had a significant positive relationship to TCC that was also greater in pines than in spruces for a given TCC, indicating a sharper curvature compared to a more progressive curve for spruce. Pine species have greater variances than spruce species. While Pinus strobus (white pine, subgenus Strobus) stands out as having greater chlorophyll and nutrient concentrations than the other three pines (subgenus Pinus). Overall, pines showed less downregulation of chlorophyll pigment concentrations than spruces in response to eCO2 and DRT. There was strong genetic control for chlorophyll pigments and most macronutrients.

Genetics and Genomic basis of Stay-green Trait

Staygreen is one such trait in which genotypes possessing this trait maintain more photo synthetically active leaves (& less senescent) than genotypes not possessing this trait. Delay of leaf senescence also known as stay-green character, has been identified as an important component in the genetic improvement of several crops to promote stress tolerance and yield gain. Although the stay-green phenotype is superficially similar in all species and genotypes, the genetic and physiological routes the traits are diverse. Photosynthetically active leaves for longer period depends on the concentration of chlorophyll pigment absorbing sunlight for photosynthesis. An multi dimensional approach for studying the senescence pathway rather than studying only the physiological role made a significant role in improvement. Hence new approaches like genomics, proteomics and metabolomics studies are necessary to understand the various transcription factors involved in regulating the leaf senescence process. Therefore, this review has aimed to bring light to major aspects of the stay-green character, showing its potential use in plant breeding.

Allelopathic Potentiality of Euphorbia hypericifolia L. on Germination and Seedling Development of Sympatric Crops and Weeds

Euphorbia hypericifolia, a non-native herbaceous weedy plant was found to often form disproportionately dense, virtually monospecific stands in the Mount Bambouto Caldera, Cameroon. This observation is within the purview of allelopathy and is attributed to the release of botanicals by non native plants that harm naïve native flora, creating significant problems for agriculture and the environment. We investigated if the invasiveness of E. hypericifolia could be explained by its allelopathic potential at varying concentrations on five indicator plants. The results showed that the leaf, root and stem aqueous extracts of the plant exhibited significant inhibitory effects on the germination, radicle and plumule lengths of Biden pilosa, Amaranthus spinosus, Lactuca sativa, Zea mays and Lycopersicon esculentum at 100 % by 75.0, 69.4, 95.6, 28.0 and 97.2 %, respectively. The leaf extract was the most potent, while the stem extract was the least. The extract of E. hypericifolia was stimulatory (Lower concentrations) and inhibitory to the germination and growth of the test plants and its effect was concentration-dependent with the roots of target plants being more sensitive to the extracts than the plumule. L. esculentum was the most susceptible species to E. hypericifolia extracts while Z. mays was more tolerant than any of the tested plants. Results of total chlorophyll pigment accretion showed declining levels of chlorophyll detected in the leaves of tomato transplants cultivated in the augmented soils with rising dosage of the leaf residue of E. hypericifolia. B. pilosa planted on E. hypericifolia infested soil (EIS) showed very poor emergence recording only 7.5 % after 6 weeks as compared to 83.0 % in non E. hypericifolia infested soil (NIS). Qualitative phytochemical screening indicates E. hypericifolia is rich in secondary metabolites including alkaloids, glycosides, flavonoids, phenolics, tanins, Steriods and saponins. Acetone was the best extractant amongst the solvents used. This study has proven the allelopathic potential of E. hypericifolia and revealed some allelochemicals that may be exploited for the development of bioherbicides and plant growth promotion from natural products.

The effect of arid conditions on productivity and elements of photosynthetic activity of winter soft wheat

The current paper has presented the estimating results of the effect of vegetation conditions on a leaf area index, preservation of chlorophyll pigment and productivity of the winter common wheat samples developed by the ARC “Donskoy”. The study was conducted in the laboratory of plant physiology in 2017-2020. There has been used the following methodology: the leaf areas were determined by the Nichiporovich's method (1955), the leaf area index during the periods of ear formation and flowering was estimated according to S.A. Tarasenko (2015). The chlorophyll content in the leaves of winter wheat varieties was assessed by the Shmatko's method (1976). The study results have identified that the leaf area indices and the chlorophyll content in leaves during the vegetation period changed according to the drought resistance degree of plants and depended mainly on the root moisture supply and on the studied genotype. In the conditions of insufficient moisture supply the varieties Krasa Dona, Asket, Etyud and Volny Don formed the maximum values of a leaf area index and preservation of chlorophyll pigment.

Kandungan Klorofil Cymodocea serrulata Pada Kedalaman Berbeda di Perairan Pulau Panjang Jepara

Klorofil merupakan faktor utama yang mempengaruhi fotosintesis. Cymodocea serrulata membutuhkan intensitas cahaya yang cukup tinggi untuk melaksanakan proses fotosintesis. Perbedaan intensitas cahaya terhadap lamun tersebut diduga akan mempengaruhi pembentukan klorofil, sehingga penelitian ini dilakukan untuk mengetahui pengaruh perbedaan kedalaman perairan terhadap kandungan klorofil C. serrulata. Penelitian ini menggunakan metode spektrofotometri untuk mengetahui absorbansi pigmen klorofil daun lamun C. Serrulata. Analisis statistika digunakan untuk mendeskripsikan pengaruh kecerahan perairan dan stasiun lokasi terhadap kandungan klorofil lamun C.serrulata. Berdasarkan hasil penelitian, kandungan klorofil tertinggi terdapat di kedalaman 1 meter yaitu sebesar 3,061 µg/l, sedangkan kandungan klorofil terendah terdapat di kedalaman 3 meter yaitu sebesar 1,509 µg/l. Kandungan klorofil menurun seiring dengan bertambahnya kedalaman, yang dipengaruhi oleh kecerahan perairan dan kadar TSS yang dapat menghambat penetrasi cahaya yang menembus perairan. Chlorophyll is the main factor that affects photosynthesis. Cymodocea serrulata requires a high intensity of the light to carry out the process of photosynthesis. In this case, the differences in light intensity will affect the formation of chlorophyll in seagrass leaves. This study aims to determine the effect of different depths on the chlorophyll content of C. serrulata. Therefore, this study used a spectrophotometric method to determine the absorbance of chlorophyll pigment in C. serrulata. Statistical analysis used to describe the water transparency and sampling station on chlorophyll content. Based on the study results, the highest chlorophyll content has found in 1 meter depth of the sea, which is equal to 3,061 µg/l and the lowest chlorophyll content in 3 meter depth of the sea equal to 1,509 µg/l. It can be concluded that the chlorophyll content decreased while the increasing of the depth due to the water transparency and TSS levels, which can inhibit the penetration of light through the water.