scholarly journals Effects of lead on growth, osmotic adjustment, antioxidant activity and photosynthetic responses in Phoebe chekiangensis seedlings

2020 ◽  
Vol 48 (3) ◽  
pp. 1637-1648
Author(s):  
Yujie YANG ◽  
Wenjie LI ◽  
Xinru HE ◽  
Die HU ◽  
Yongjun FEI

Experiments were conducted on 1-year Phoebe chekiangensis seedlings treated by different concentration (0, 300, 600, 900, 1200 mg/L) of Pb (NO3)2. Sixty days later, determination was implemented on seedling growth, physiological and photosynthetic parameters. The results showed that the lower concentration treated could promote the growth of the seedlings. But with the increase of concentration of lead, P. chekiangensis seedling height increment, ground diameter growth, whole biomass, total root surface area, root volume, total root length and root activity decreased, while root-shoot ratio present a rising trend. With the increase of concentration of Pb(NO3)2 solution, the membrane permeability and MDA content of P. chekiangensis seedlings showed a trend of rise after the first reduce; the protein content and chlorophyll content presented a trend of decrease after the first increase; while the POD, SOD and CAT activity increased firstly but decreased afterwards; the net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate were all increase at first then decrease, which indicated that protection enzyme activity and membrane was damaged thus the growth of P. chekiangensis seedlings was inhibited.

2019 ◽  
Vol 12 (1) ◽  
pp. 73
Author(s):  
Mokhtar Baraket ◽  
Sondes Fkiri ◽  
Ibtissam Taghouti ◽  
Salma Sai Kachout ◽  
Amel Ennajah ◽  
...  

In north Tunisia, the Quercus suber L. forests have shown a great decline indices as well as a non-natural regeneration. The climate changes could accentuate this unappreciated situation. In this study, the effect of water deficit on physiological behavior of Quercus suber seedlings was investigated. Photosynthetic responses of 15 months old Cork oak seedlings grown for 30 days under 40% and 80% soil water water content (control) were evaluated. Results showed a negative effect of water deficit and a positive effect of the intercellular CO2 concentration increase both on photosynthesis and transpiration. Stomata conductance might play a major role in balancing gas exchanges between the leaf and its environment. Moreover, global warming could negatively affect carbon uptake of Cork oak species in northern Tunisia. Elevated CO2 leaf content will benefit Cork oak growing under water deficit by decreasing both photoysnthesis and transpiration, which will decrease either the rate or the severity of water deficits, with limited effects on metabolism. the results suggest that high intercellular CO2 concentration could increase water use efficiency among Cork oak species.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1921
Author(s):  
Yafei Wang ◽  
Guoxin Ma ◽  
Xiaoxue Du ◽  
Yong Liu ◽  
Bin Wang ◽  
...  

Abiotic and biotic stresses both decrease the quality and quantity of cultivated plants. In this study, in order to see the responses of cucumber plants to drought stress and cucumber downy mildew infection, downy mildew infestation at different two levels, B1 (disease infestation) and B2 (no disease infestation), along with three fertigation requirement levels, full fertigation T1, moderate nutrient solution deficit T2 and severe nutrient solution deficit T3, were applied in a greenhouse. Thus, six treatments, i.e., B1T1, B1T2, B1T3, B2T1, B2T2 and B2T3, were set. The leaf gas-exchange parameters were significantly increased under CK (control experiment, B2T1: no disease infestation and full irrigation) treatment, and leaf photosynthesis rate, transpiration rate and stomatal conductance were significantly decreased under the B1T1 treatment. Leaf intercellular CO2 concentration was significantly increased under B1T1 treatment. Leaf photosynthesis rate, transpiration rate, intercellular CO2 concentration and stomatal conductance were significantly decreased under B1T2, B1T3, B2T2 and B2T3 treatments. Compared with treatment CK (B2T1), the plant height of cucumber under B1T1, B1T2, B1T3, B2T2 and B2T3 treatments decreased by 11.41%, 19.05%, 27.48%, 7.55% and 10.62%, respectively; the stem diameter of cucumber under B1T1, B1T2, B1T3, B2T2 and B2T3 treatments decreased by 5.70%, 13.45%, 23.03%, 9.46% and 15.74%, respectively; and leaf area of cucumber under B1T1, B1T2, B1T3, B2T2 and B2T3 treatments decreased by 22.79%, 38.68%, 58.28%, 13.76% and 29.96%, respectively. The root–shoot ratio of cucumber under B1T1, B1T2, B1T3, B2T1, B2T2 and B2T3 treatments was 3.16%, 2.99%, 4.11%, 3.92%, 3.13% and 3.63%, respectively. The root–shoot ratio of cucumber was the highest under the B1T3 treatment.


Author(s):  
Quanhong Lin ◽  
Di Tian ◽  
Changti Zhao ◽  
Zhenyue Liu ◽  
Bin Wang ◽  
...  

Using traditional photosynthesis-intercellular CO concentration (A-C) response (TACiR) curves to obtain the maximum rates of ribulose-1,5-bisphosphate carboxylase oxygenase carboxylation (V) and electron transport (J) is time-consuming and labor-intensive. Instead, the rapid A-C response (RACiR) technique provides a potential way with high efficiency. However, multiple parameter settings of RACiR technique for different plant life forms remain unclear. Here, we used Li-Cor 6800 to test the applicability and optimum parameter settings of RACiR curves for evergreens and herbs. We set 11 groups of [CO], i.e., R1 (400-1500 ppm), R2 (400-200-800 ppm), R3 (420-20-620 ppm), R4 (420-20-820 ppm), R5 (420-20-1020 ppm), R6 (420-20-1220 ppm), R7 (420-20-1520 ppm), R8 (420-20-1820 ppm), R9 (450-50-650 ppm), R10 (650-50 ppm) and R11 (650-50-650 ppm), and made contrasts between TACiR and RACiR curves. We found that V and J calculated by TACiR and RACiR overall showed no significant differences across 11 [CO] gradients (P<0.05). The efficiency and accuracy of R2, R3, R4, R9 and R10 showed higher superiority than others. Moreover, the accuracy of manual empty chamber correction method was higher than the automatic method. In conclusion, the RACiR technique could be generally used to obtain photosynthetic parameters with higher efficiency than traditional methods for various life forms.


2022 ◽  
Vol 52 (3) ◽  
Author(s):  
Liuzheng Yuan ◽  
Jiayou Liu ◽  
Zhiyong Cai ◽  
Huiqiang Wang ◽  
Jiafeng Fu ◽  
...  

ABSTRACT: The responses of two maize (Zea mays L.) cultivars, ‘LY336’ (shade tolerant) and ‘LC803’ (shade sensitive), to shade stress in a pot experiment conducted in the 2015 and 2016 growing seasons were investigated. The impact of 50% shade stress treatment on shoot biomass, photosynthetic parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content was evaluated. The shoot biomass of the two maize hybrids was decreased significantly by shade stress treatment, for shade stress 7 d, the LC803 and LY336 were reduced by 56.7% and 44.4% compared with natural light. Chlorophyll fluorescence parameters of LY336 were not significantly affected by shade stress, whereas those of LC803 were significantly affected, the Fo increased under shade stress; however Fm, FV/FM and ΦPSII were decreased under shade stress. Among photosynthetic parameters measured, net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate were significantly decreased compared with natural light, LY336 and LC803 reduction by 28.0%, 22.2%, 57.7% and 35.5%, 18.9%, 62.4%; however, intercellular CO2 concentration (Ci) was significantly increased, for the two cultivars. Under shade stress for different durations (1, 3, 5, 7 d), Pn, Gs, Ci, and MDA content differed significantly between the two cultivars. Results indicated that different maize genotypes showed different responses to shading. Shade-tolerant genotypes are only weakly affected by shade stress.


Author(s):  
Junyao Lyu ◽  
Feng Xiong ◽  
Ningxiao Sun ◽  
Yiheng Li ◽  
Chunjiang Liu ◽  
...  

Volatile organic compound (VOCs) emission is an important cause of photochemical smog and particulate pollution in urban areas, and urban vegetation has been presented as an important source. Different tree species have different emission levels, so adjusting greening species collocation is an effective way to control biogenic VOC pollution. However, there is a lack of measurements of tree species emission in subtropical metropolises, and the factors influencing the species-specific differences need to be further clarified. This study applied an in situ method to investigate the isoprene emission rates of 10 typical tree species in subtropical metropolises. Photosynthesis and related parameters including photosynthetic rate, intercellular CO2 concentration, stomatal conductance, and transpiration rate, which can influence the emission rate of a single species, were also measured. Results showed Salix babylonica always exhibited a high emission level, whereas Elaeocarpus decipiens and Ligustrum lucidum maintained a low level throughout the year. Differences in photosynthetic rate and stomatal CO2 conductance are the key parameters related to isoprene emission among different plants. Through the establishment of emission inventory and determination of key photosynthetic parameters, the results provide a reference for the selection of urban greening species, as well as seasonal pollution control, and help to alleviate VOC pollution caused by urban forests.


2021 ◽  
Vol 13 (22) ◽  
pp. 12335
Author(s):  
Ung Yi ◽  
Sakimin Siti Zaharah ◽  
Siti Izera Ismail ◽  
Mohamed Hanafi Musa

Neem leaf extracts (NLEs) have frequently been used to inhibit plant diseases and for the development of bio-fertilizer, leading to the commercial exploitation of this tree. However, previous studies have indicated contradictory outcomes when NLE was used as an antifungal disease treatment and bio-fertilizer applied through the soil on several crops, including banana. Therefore, the present investigation was undertaken to examine the physicochemical properties of soil, the growth performance of crops, and the severity of diseases caused by Fusarium oxysporum (Foc) on Cavendish bananas treated with aqueous NLE. Banana plants associated with the fungus were significantly affected by high disease severity and symptoms index (external leaves and internal rhizome), a high infection percentage of Fusarium wilt (%), dropping off of leaves as well as rotting of the root. Meanwhile, it was observed that the application of extract significantly improved the crop height, stem diameter, root size and distribution (root surface area, root diameter, and root volume), root–shoot ratio, as well as the soil physicochemical properties (CEC, N, p, K, Ca, and Mg), which enhanced resistance to Fusarium wilt diseases. We conclude that the application of NLE solution promotes better growth of Cavendish banana plants, soil physicochemical properties, and resistance to Fusarium wilt infection.


2013 ◽  
Vol 726-731 ◽  
pp. 81-84
Author(s):  
Wu Xing Huang ◽  
Cong Ren ◽  
Jing Qing Gao

Two Rumex japonicus populations, one from copper (Cu) mine and the other from uncontaminated site, were studied for root morphology and biomass under Cu stress. Main root length and number of tips of the two populations were both significantly inhibited by Cu treatments. However, those of metallicolous population (MP) were higher than non-metallicolous population (NMP) under Cu stress. Cu treatments significantly inhibited root surface area in NMP while MP showed little difference from control. Cu treatments inhibited average root diameter and root/shoot ratio in NMP, but those in MP were significantly higher than control. Cu treatments significantly inhibited shoot biomass and root biomass in NMP. These results suggested that more assimilates allocated to root and the average root diameter increased under Cu stress to form a greater and stronger root might be partly reasons why R. japonicus can colonize the Cu enriched soils.


2010 ◽  
Vol 40 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
Inês Cechin ◽  
Natália Corniani ◽  
Terezinha de Fátima Fumis ◽  
Ana Catarina Cataneo

The effects of water stress and rehydration on leaf gas exchange characteristics along with changes in lipid peroxidation and pirogalol peroxidase (PG-POD) were studied in mature and in young leaves of sunflower (Helianthus annuus L.), which were grown in a greenhouse. Water stress reduced photosynthesis (Pn), stomatal conductance (g s), and transpiration (E) in both young and mature leaves. However, the amplitude of the reduction was dependent on leaf age. The intercellular CO2 concentration (Ci) was increased in mature leaves but it was not altered in young leaves. Instantaneous water use efficiency (WUE) in mature stressed leaves was reduced when compared to control leaves while in young stressed leaves it was maintained to the same level as the control. After 24h of rehydration, most of the parameters related to gas exchange recovered to the same level as the unstressed plants except gs and E in mature leaves. Water stress did not activated PG-POD independently of leaf age. However, after rehydration the enzyme activity was increased in mature leaves and remained to the same as the control in young leaves. Malondialdehyde (MDA) content was increased by water stress in both mature and young leaves. The results suggest that young leaves are more susceptible to water stress in terms of gas exchange characteristics than mature leaves although both went through oxidative estresse.


2012 ◽  
Vol 39 (3) ◽  
pp. 199 ◽  
Author(s):  
Violeta Velikova ◽  
Tommaso La Mantia ◽  
Marco Lauteri ◽  
Marco Michelozzi ◽  
Isabel Nogues ◽  
...  

We investigated the consequences of recurrent winter flooding with saline water on a lemon (Citrus × limon (L.) Burm.f.) orchard, focussing on photosynthesis limitations and emission of secondary metabolites (isoprenoids) from leaves and fruits. Measurements were carried out immediately after flooding (December), at the end of winter (April) and after a dry summer in which plants were irrigated with optimal quality water (September). Photosynthesis was negatively affected by flooding. The effect was still visible at the end of winter, whereas the photosynthetic rate was fully recovered after summer, indicating an unexpected resilience capacity of flooded plants. Photosynthesis inhibition by flooding was not due to diffusive limitations to CO2 entry into the leaf, as indicated by measurements of stomatal conductance and intercellular CO2 concentration. Biochemical and photochemical limitations seemed to play a more important role in limiting the photosynthesis of flooded plants. In young leaves, characterised by high rates of mitochondrial respiration, respiratory rates were enhanced by flooding. Flooding transiently caused large and rapid emission of several volatile isoprenoids. Emission of limonene, the most abundant compound, was stimulated in the leaves, and in young and mature fruits. Flooding changed the blend of emitted isoprenoids, but only few changes were observed in the stored isoprenoids pool.


Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Yu Liu ◽  
Ji Qian ◽  
Xin Yang ◽  
Bao Di ◽  
Juan Zhou

Abstract Background Traditional measurements of apple seedling roots often rely on manual measurements and existing root scanners on the market. Manual measurement requires a lot of labor and time, and subjective reasons may cause the uncertainty of data; root scanners have limited scanning size and expensive. In case of fruit roots, coverage and occlusion issues will occur, resulting in inaccurate results, but our research solved this problem. Results The background plate was selected according to the color of the seedling roots; the image of the roots of the collected apple seedlings was preprocessed with Vision Development Module by combining image and Labview. The root surface area, average root diameter, root length and root volume of apple seedlings were measured by combining root characteristic parameters algorithm. In order to verify the effectiveness of the proposed method, a set of measurement system for root morphology of apple seedlings was designed, and the measurement result was compared with the Canadian root system WinRHIZO 2016 (Canada). With application of SPSS v22.0 analysis, the significance P > 0.01 indicated that the difference was not significant. The relative error of surface area was less than 0.5%. The relative error of the average diameter and length of the root system was less than 0.1%, and the relative error of the root volume was less than 0.2%. Conclusions It not only proved that the root surface area, average root diameter, root length and root volume of apple seedlings could be accurately measured by the method described herein, which was handy in operation, but also reduced the cost by 80–90% compared with the conventional scanner.


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