Plant, Soil and Environment - In Press
Dynamics of Cry1Ac Protein and Soil Enzyme Activity in Rhizosphere of Transgenic Bt Oilseed RapeOriginal Paper
zheng-Jun Guan, Wei Wei, Yanlin Huo, C. Neal Stewart Jr., Zhixi Tang
The influences of transgenic Bt plants on the soil ecological environment have been a research hotspot in biosafety research. Soil enzyme activities can reflect the strength and direction of various biochemical processes in the soil and could be susceptible to the transgenic Bt plants. In this study, three insect-resistant transgenic Bt oilseed rape events (GT1, GT5 and GT9) under field conditions were used to analyze the dynamics of Cry1Ac protein and the changes in soil enzyme activities in the rhizosphere soil of transgenic Bt plants during different growth stages over two successive cultivation years. The results showed that, compared to the non-transgenic control plant ‘Westar’, the amount of Cry1Ac protein in the rhizosphere soil of the three transgenic oilseed rape events was significantly higher during the flowering and podding stages in the first cultivation year. Additionally, in the second cultivation year, transgenic GT1 and GT9 had significantly higher amounts of Cry1Ac protein in the rhizosphere soil during the flowering stage, and all three transgenic oilseed rape events had significantly higher amounts of Cry1Ac protein in the rhizosphere soil during the podding stage. Over the two successive cultivation years, the sucrase activity in the rhizosphere soil of transgenic events had significant changes during bolting, flowering and podding stages; while all three transgenic events exhibited significant changes in phosphatase activity during the four different stages. Furthermore, different transgenic events showed varying significant changes in urease and protease activities during the bolting, flowering and podding stages of the first year, and all three transgenic events had significant changes of dehydrogenase activities during the four different stages of the second cultivation year. PCA and correlation analysis unequivocally demonstrated a profound correlation between the Cry1Ac protein and five soil enzyme activities, as well as a strong interconnectedness among those five soil enzyme activities. These findings indicate that the amount of insecticidal crystal proteins in the rhizosphere soil of transgenic Bt (Cry1Ac) oilseed rape changed with different growth periods, and the enzyme activities in the rhizosphere soil of transgenic Bt oilseed rape plants undergo significant changes over two successive planting years.
Enhanced maize yield and nitrogen efficiency with low molecular weight fulvic acid: insights into chlorophyll a/b ratio and nitrogen metabolizing enzyme activityOriginal Paper
Fugui Li, Shujie Zhang, Longhang Chai, Zhiqiang Guo, Peipei Li, Yanlai Han, Yi Wang
This study investigates the impact of various molecular weights (MWs) of fulvic acid (FA) on maize growth, grain yield, and nutrient uptake under different nitrogen levels (NLs). A 2×3 balanced design was employed, with high (0.2 g/kg N) and low (0.05 g/kg N) NLs, and three FA MW ranges (W1≤3000D, 300010,000D) were applied at 25 mg/kg in soil. Significant interactions between NLs and FA MWs were observed in chlorophyll a/b ratio, nitrate reductase and glutamate dehydrogenase activities, nitrogen content, and nitrogen uptake efficiency. Overall, under different NLs, FA application reduced chlorophyll a/b ratio, increased nitrogen metabolism enzyme activities, promoted maize growth, and thereby improved grain yield and nitrogen fertilizer uptake efficiency. Additionally, the promotion effect of low MW FA on these indicators outweighed that of high MW FA, yet the latter exhibited a more pronounced effect on increasing grain nitrogen concentration. Structural equation model analysis revealed direct effects of chlorophyll content, nitrogen accumulation, nitrogen uptake efficiency, NLs and FA MWs on maize grain yield, with FA MWs negatively impacting yield.
Gas exchange and chlorophyll fluorescence of four sorghum genotype under drought stress and rehydratationOriginal Paper
František Hnilička, Helena Hniličková, Tomáš Rýgl
Water deficit (drought) is an important environmental factor affecting physiological processes in plants. The present work focuses on the study of changes in physiological responses of juvenile plants (plants in the vegetative phase of growth BBCH 14-16) of selected sorghum genotypes Dokok, 30485, Barnard Red and Ruzrok to water deficit and after rehydration. Water deficit affected the observed physiological parameters – gas exchange, chlorophyll fluorescence. Genotypic differences were also confirmed, with Dokok appearing to be the more sensitive genotype and Ruzrok and Barnard Red appearing to be tolerant. Following rehydration, these parameters increased, but did not reach the levels of the control plants. A significant decrease in photosynthetic rate (Pn), transpiration (E) and fluorescence compared to the control was found in the water-deficient variant twice for 10 days and 6 days between rehydration periods. Only in the variant where water deficit (14 days) was followed by irrigation (10 days), transpiration increased in genotype 30485. Chlorophyll fluorescence (Fv/Fm) also decreased significantly in this variety. The results obtained suggest that the duration of rehydration should be longer than 14 days.
Effects of cultivation duration of the crop and growth stages on rhizosphere soil physicochemical properties, enzyme activities, and microbial communities of ginseng under forestOriginal Paper
Yuchi Zhao, Qiuyu Wang, Shuaiqi Feng, Yang Zhang, Weiwei Dong, Wenxiu Ji
In this study, Illumina MiSeq sequencing of 16S and ITS2 rRNA genes were used to determine the dynamic changes in bacterial and fungal communities and soil properties and enzyme activities in rhizosphere soil of ginseng under forest after 5, 10 and 15 years of cultivation and different growth stages. Results showed that the changes were particularly prominent in 10-year-old ginseng under forest, and the trends of organic carbon, alkaline hydrolyzed nitrogen, and available potassium were extremely similar in different duration of the crop, especially in the middle stage of rapid root growth, when soil nutrient consumption was severe, and soil enzyme activities of rhizosphere were significantly reduced. The observed changes in soil properties and enzyme activities caused by cultivation duration of the crop and growth stage could be explained by the variations in the microbiome. The microbial composition of 10-year-old ginseng under forest has undergone significant changes, at the genus level, both Acinetobacter bacteria and Kazachstania fungi exhibited a higher abundance; the abundance of Bacillota (Firmicutes), and Candidatus Udaeobacter with significantly lower abundance. This study initially revealed the changes in nutrient utilization of ginseng under forest at different cultivation duration of the crop and different growth stages, as well as the regulatory role played by microbes in this process preliminarily. We consider 10 years to be a critical stage for long-term cultivation of ginseng under forest, during which it is more sensitive to environmental factors and may exhibit special dynamic changes affecting its growth and quality. This provides a reference for further precision planting and harvesting of ginseng under forest.
Prohexadione calcium enhances wheat tolerance to water stress by improving water balance, antioxidant metabolism and photosynthetic performanceShort Communication
Ziyang Zhang
This study explored whether and how prohexadione calcium (Pro-Ca) regulated wheat tolerance to water stress (WS). The results manifested that WS increased the activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, the contents of antioxidants ascorbic acid (AsA) and glutathione (GSH), MDA, EL, and the contents of osmolytes soluble protein (SP), soluble sugars (SS) and proline (Pro). However, WS decreased Tr, Gs, and RWC, and inhibited photosynthetic performance and plant growth. Compared with WS alone, Pro-Ca plus WS improved wheat tolerance to WS by enhancing the activities of above antioxidant enzymes and the contents of above antioxidants, which in turn decreased MDA content and EL. Meanwhile, compared with WS alone, Pro-Ca plus WS increased the contents of osmolytes SP, SS and Pro, RWC, Tr and Gs. Besides, Pro-Ca plus WS enhanced the photosynthetic performance by improving chlorophyll (Chl) and carotenoid (Car) contents, photosynthetic rate and Chl fluorescence parameter maximum photochemical efficiency of PSII, whcih further promoted plant height and biomass. Our results suggested that Pro-Ca can be applied as an effective agent in enhancing wheat tolerance under water deficit.
Serendipita indica improve seed germination and seedling growth of Lolium multiflorum Lam. through amelioration of osmotic adjustment, nutrient accumulation and Na + /K + homoeostasis under salinity conditionOriginal Paper
Binghua Liu, Xinghong Liu, Lianjia Yu, Hailin Ma, Fangchun Liu, Lin Peng
A pot experiment was carried out to determine the effect of Serendipita indica on salt response of Lolium multiflorum Lam. Although the salinity decreased the root colonization of S. indica by 28.34%, successful colonization of S. indica increased the seed germination rate, fresh weight, leaf relative water content and chlorophyll content by 28.09%, 59.01%, 38.78% and 28.80%, respectively, compared with uncolonized seedlings. Under salinity, leaf malondialdehyde content, leaf relative electrical conductivity, as well as Na+ content and Na+/K+ ratio in leaves and roots of S. indica-colonized seedlings were decreased by 33.99%, 33.31%, 63.40 % and 47.42%, 85.66 % and 55.88 %, respectively, compared with uncolonized seedlings. Meanwhile, compared with uncolonized seedlings under salinity, the contents of proline in leaves, N, P and K+ in leaves and roots of the S. indica-colonized seedlings were increased by 47.47%, 45.69% and 30.05%, 41.77% and 19.51%, 19.18% and 155.00%, respectively. These results indicate that S. indica colonization confers salt tolerance in L. multiflorum seedlings by enhancing osmotic adjustment via actively accumulating proline and K+, increasing the uptake of nutrients such as N and P, and improving Na+/K+ homoeostasis. The study would provide a new idea for the combined application of salt-tolerant plants and symbiotic microorganisms in the ecological restoration of saline-alkali lands.
Roots of Lupinus angustifolius L. and enzyme activities in soil contaminated by toxic elementsOriginal Paper
Daniela Pavlíková, Milan Novák, Veronika Zemanová, Jindřich Černý
The impact of toxic elements (TEs) contaminating the root zone of Lupinus angustifolius L. on enzymatic activities, nitrification rate, and changes in the root system was evaluated. Lupine was cultivated in a pot experiment using two types of soil – Control and Contamination (with high degree of As, Cd, Pb, and Zn contamination). After harvesting lupine biomass, enzyme activities (β-glucosidase, acid phosphatase, arylsulphatase, lipase, chitinase, cellobiohydrolase, alanine aminopeptidase, and leucine aminopeptidase) in soils were analysed. Enzyme activities decreased with TE soil contamination. According to our results, arylsulphatase was found to be the most sensitive soil enzyme to TEs. The nitrification rate is closely related to soil contamination and plant activity, as it stimulates microbial growth and multiplication through root exudates. The close correlations confirmed this relationship (r = 0.73−0.99). An increasing trend in TE contents in the roots was observed with soil contamination. Plant hormones are crucial in regulating root growth and development under stress conditions. The levels of determined phytohormones in our experiment (auxins, abscisic acid (ABA), salicylic acid (SA), and bioactive cytokinins (bCKs)) were lower in the Contamination compared to the Control. Correlations confirmed a significant negative relationship between the TEs content in the roots and the contents of phytohormones (auxins: r = -0.96 to -0.97; ABA: r = -0.83 to -0.86; SA: r = -0.95 to -0.99, bCKs: r = -0.87 to -0.93). The ratios of these hormones (not their absolute values) appear to be the determining factor for regulating root development and protecting plants from oxidative stress.
Anti-diabetic Effect of Rice Extract Constituents through the Molecular Inhibition of α-Amylase and α-Glucosidase ActivityOriginal Paper
Subhashini Ramakrishnan, Thomas Jebastin, Sumathy Raj, Ramathilaga Ariyamuthu, Rithik Selvaraj, Najat A. Bukhari A., Ashraf Atef Hatamleh Atef Hatamleh, Anis Ahamed Ahamed
Carbohydrate digestive enzymes like α-Amylase and α-Glucosidase can be used to treat and manage Diabetes. By inhibiting these enzymes, carbohydrate digestion slowed down, lowering the level of glucose entry into the bloodstream and prevents postprandial hyperglycemia. However, the effectiveness of current antidiabetic agents is limited due to their adverse effects. Therefore, the current study explored natural inhibitors from the methanol extract of rice to combat this issue. Through an integrated approach, four different rice varieties were analyzed, and found that red rice methanol extract compounds Stigmasterol and 1,2-benzenedicarboxylic acid interacted with α-amylase and α-glucosidase. Additionally, further research on Stigmasterol directs the structure-activity relationship studies that aid in managing Type2 Diabetes Mellitus
Response of maize (Zea mays L.) on yield, physiology and stomatal behavior, under two different elevated CO2 concentrations. Do these anatomical changes affect the physiology of the C4 crop plant under high CO2 conditions?Original Paper
Khan Ira, Vanaja M., Sathish P., Faizan Mohammad, Soysal Sipan, Rajput Vishnu D., Djalovic Ivica, Trivan Goran, Alam Pravej
Rising CO2 concentration in the atmosphere is a matter of global concern and is posing apprehension on how the plants will adapt to the changing environment. Various studies have proved that under high CO2 levels, plant physiology alters and affects the plant functioning. However, under elevated CO2, the stomatal characters and their relation with physiological responses are still not yet clear. In order to find out theses changes in the stomatal parameters at ambient and two elevated CO2 (550ppm and 700ppm) levels, four genotypes of maize (Zea mays L.) viz. DHM-117, Harsha, Varun and M-24 were grown in Open Top Chambers. In the study it was observed that the stomatal density increased, stomatal size altered, stomatal conductance (gs) and transpiration rate (Tr) decreased under elevated CO2 (eCO2) while Photosynthetic rates (Anet), Water use efficiency (WUE), yield and biomass, of which especially the reproductive biomass increased. Under eCO2, stomatal and physiological changes were genotypic and CO2 concentration specific. The increase in stomatal density at eCO2 was mainly due to increased abaxial stomatal density. The improved Anet and reduced Tr at 550ppm, improved the WUE in the plants while this response was not observed at 700ppm. These results elucidate that this C4 crop responded positively up to 550ppm of CO2 concentrations and beyond this the impact was minimum
Alleviating Cadmium Toxicity in Maize Plants: Role of Glycine Betaine in Enhancing Photosynthetic Efficiency, Water Status and Antioxidant Defense MechanismOriginal Paper
Abeer Elhakem
The issue of heavy metals (HMs) contamination poses a significant challenge in the environment, exerting a severe impact on the growth and productivity of crops. Cadmium (Cd) is specifically identified as the seventh heavy metal among the top 20 pollutants, primarily due to its elevated phytotoxicity and its solubility in water. In the current study, foliar application of glycine betaine (GB) (500 µM) investigated the toxic effects of cadmium (Cd) in maize plants subjected to two Cd concentrations (50 and 100 µmol) as CdCl2. The maize plants exposed to Cd stress exhibited a massive reduction in photosynthetic pigments [Chlorophyll a (Chl a), Chlorophyll b (Chl b), carotenoids, and total pigments], gas exchange parameters [transpiration rate (Tr), net photosynthetic rate (Pn), intracellular CO2 concentration (Ci), and stomatal conductance (Gs)], relative water content (RWC), and some organic osmolytes content [total soluble protein (TSS), and total soluble sugar (TSS)]. These impacts were significant with the 100µmol CdCl2 treatment. Moreover, Cd increased the nonenzymatic antioxidants levels [proline, ascorbic acid (AsA), glutathione (GSH)] as well as the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR). On the other hand, GB application efficiently relieved the Cd toxic impacts on maize and maintained higher gas exchange parameters, photosynthetic pigments, RWC, and organic osmolytes. In addition, the exogenous application of GB added more enhancement to the antioxidative system (enzymatic and nonenzymatic). These results imply that GB could significantly preserve maize growth under Cd toxicity conditions by maintaining photosynthetic characteristics, water status, and antioxidant system. This suggests an enhancement in the plant's resilience to stress induced by heavy metals.