scholarly journals Brassinosteroids Regulate Antioxidant System and Protect Chloroplast Ultrastructure of Autotoxicity-Stressed Cucumber (Cucumis sativus L.) Seedlings

Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 265 ◽  
Author(s):  
Ping Yang ◽  
Muhammad Azher Nawaz ◽  
Fuxin Li ◽  
Lisha Bai ◽  
Jie Li
Keyword(s):  
Net Photosynthetic Rate ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Soluble Sugar ◽  
Chloroplast Ultrastructure ◽  
Dry Weight ◽  
Antioxidant Defense System ◽  
Stress Conditions ◽  
Vegetable Crops ◽  
Cucumis Sativus L

Autotoxicity is a common problem being faced in protected vegetable cultivation system. Phytoremediation of plant autotoxicity is an emerging concept to minimize deterioration of soil environment and reduction of yield and quality of vegetable crops. Brassinosteroids (BRs) have been reported as a potential phytohormone to assist phytoremediation. However, the effects of BRs-induced autotoxicity stress on plant growth, photosynthesis and antioxidant defense system are poorly understood. Hence, we focused on the changes in physiological characteristics and ultrastructure of cucumber leaves in response to the application of 24-epibrassinolide (EBR) under autotoxicity stress conditions. The results showed that leaf area, plant height, fresh weight and dry weight of cucumber were obviously decreased under autotoxicity stress conditions. EBR application obviously improved the phenotypic characteristics of cucumber seedlings. Chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate of cucumber leaves were markedly reduced under autotoxicity stress conditions. Application of EBR improved the photosynthetic pigments (chlorophyll a by 15.80%, chlorophyll b by 18.70% and total chlorophyll content by 17.30%), net photosynthetic rate by 36.40% and stomatal opening of leaves under autotoxicity stress conditions. EBR application also maintained the integrity of chloroplast and thylakoid structures under autotoxicity stress conditions. The activity of catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) and antioxidative compounds ascorbate (AsA) and reduced glutathione (GSH) contents were markedly decreased, however, these were obviously increased after EBR application under autotoxicity stress. EBR application also increased the soluble sugar and protein, and proline concentration by 59.70%, 7.22% and 36.58%, respectively in the leaves of cucumber, decreased malondialdehyde by 24.13% and reactive oxygen species contents (H2O2 by 35.17%, O2− by 12.01% and •OH by 16.59%), and reduced the relative permeability of the cell membrane by 14.31%. These findings suggest that EBR application enhanced the photosynthetic capacity of leaves, maintained the integrity of chloroplast and thylakoid structures, and effectively alleviated the damage of membrane caused by lipid peroxidation and root damage under autotoxicity stress conditions. The growth inhibition effect of autotoxicity stress on cucumber was reduced by EBR application.

scholarly journals Shoot and root dry weight in drought exposed tomato populations

Genetika ◽  
2014 ◽  
Vol 46 (2) ◽  
pp. 495-504 ◽  
Author(s):  
Milka Brdar-Jokanovic ◽  
Zdenka Girek ◽  
Suzana Pavlovic ◽  
Milan Ugrinovic ◽  
Jasmina Zdravkovic
Keyword(s):  
Drought Tolerance ◽  
Germplasm Collection ◽  
Dry Weight ◽  
Stress Conditions ◽  
Genotypic Differences ◽  
Vegetable Crops ◽  
Drought Treatment ◽  
Volumetric Soil Water Content ◽  
Root Dry Weight ◽  
Selection Indices

This research was conducted with the aim to among forty-one tested tomato (Lycopersicon esculentum Mill) populations distinguish those tolerant to limited water supply. Tolerance assessments were performed by using sixteen drought stress selection indices calculated on the basis of tomato shoot and root dry weight yields determined at water stress and non-stress conditions. Populations were differentiated in groups using the method of cluster analysis. The pot experiment was set in controlled greenhouse conditions and comprised optimally irrigated control and drought treatment (35.0 and 20.9% volumetric soil water content, respectively), imposed at the phase of intensive vegetative growth. The experiment was conducted at the Institute for Vegetable Crops in Smederevska Palanka, Serbia. The analyzed tomatoes exhibited significant differences in terms of response to limited irrigation, which had more pronounced effect on shoot dry weight than on the roots (average decrease of 64.4 and 35.7%, respectively). Consequently, root fraction in the total dry weight increased at drought for 68.2% on average. Shoot and root dry weights were positively correlated at optimal irrigation but not in drought, implying genotypic differences in terms of root adjustments to stress conditions. As for the calculated selection indices, substantial variation was found among the populations enabling their ranking in terms of drought tolerance. Since ranking was not the same in all cases, clustering the populations was performed taking into account all sixteen selection indices. The results of this analysis indicate that populations designated with numbers 126, 124, 131, 125, 128, 105, 101, 138, 110, 132 and 109 in Institute for Vegetable Crops germplasm collection exhibit satisfactory level of drought tolerance at vegetative phase and therefore may be used as parents in breeding programs.

Effects of Potassium Fertilizer on Diurnal Change of Photosynthesis in Stevia Rebaudiana Bertoni

2011 ◽  
Vol 343-344 ◽  
pp. 1087-1091 ◽  
Author(s):  
Lei Ma ◽  
Guang Xi Ren ◽  
Yan Shi
Keyword(s):  
Net Photosynthetic Rate ◽  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Photosynthetic Rate ◽  
Stevia Rebaudiana ◽  
Diurnal Change ◽  
Diurnal Changes ◽  
Potassium Fertilizer ◽  
Midday Depression ◽  
Stevia Rebaudiana Bertoni

The effects of potassium fertilizer on diurnal change of photosynthesis in Stevia rebaudiana Bertoni had been studied. Diurnal changes of net photosynthetic rate (Pn) and environmental and physiological traits in leaves of Stevia rebaudiana Bertoni were measured using LI-6400 portable photosynthesis system. The results showed that optimal potassium fertilizer can increased chlorophyll content and improved photosynthesis rate and decreased the chlorophyll a/b ratio. At the same time, midday depression of photosynthesis abated or disappeared.

scholarly journals Whole-Plant Response of Selected Woody Landscape Species to Uniconazole

1991 ◽  
Vol 9 (3) ◽  
pp. 163-167
Author(s):  
Stuart L. Warren ◽  
Frank A. Blazich ◽  
Mack Thetford
Keyword(s):  
Stomatal Conductance ◽  
Net Photosynthetic Rate ◽  
Leaf Area ◽  
Photosynthetic Rate ◽  
Foliar Spray ◽  
Dry Weight ◽  
Specific Leaf Weight ◽  
Whole Plant ◽  
Top Dry Weight ◽  
Leaf Dry Weight

Abstract Uniconazole was applied as a foliar spray or medium drench to six woody landscape species: ‘Sunglow’ azalea; flame azalea; ‘Spectabilis’ forsythia; ‘Compacta’ holly; ‘Nellie R. Stevens’ holly; and mountain pieris. One hundred days after uniconazole application, leaf, stem, and top dry weight of all species, except flame azalea and mountain pieris, decreased as uniconazole concentration increased. Compared to controls, stem and leaf dry weight were reduced by uniconazole 18 to 60% and 13 to 32%, respectively, depending on species and method of application. Stem dry weight was reduced to a greater degree, compared to leaf dry weight. For all species, drench application was more effective than foliar spray in reducing leaf, stem, and top dry weight. Leaf area of ‘Spectabilis’ forsythia and ‘Nellie R. Stevens’ holly decreased with increasing rates. However, specific leaf weight was not affected. Uniconazole did not significantly affect leaf net photosynthetic rate, stomatal conductance or internal leaf CO2 concentrations in ‘Spectabilis’ forsythia or ‘Nellie R. Stevens’ holly. No phytotoxicity was observed on any species.

Relationship between visual colour rating and chlorophyll content, photosynthetic rate, and some growth characteristics in couchgrass (Cynodonspp. L.)

1983 ◽  
Vol 100 (1) ◽  
pp. 221-225 ◽  
Author(s):  
M. S. Rahman
Keyword(s):  
Leaf Area ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Unit Area ◽  
Dark Respiration ◽  
Dry Weight ◽  
Chlorophyll Contents ◽  
Respiration Rates ◽  
Unit Leaf ◽  
Visual Colour

SUMMARYChlorophyll contents per unit leaf area and unit dry weight, chlorophylla:bratio, visual colour rating, specific leaf area, and leaf fresh weight: dry weight ratios were estimated for 12 couch (bermudagrass) varieties (Cynodonspp. L.) in winter (July) and spring (October). Net photosynthetic and dark respiration rates were estimated in winter only.The chlorophyll contents per unit leaf area were higher in all varieties in spring than in winter, but per unit weight were more variable. The varieties differed substantially in the net photosynthetic and dark respiration rates. The specific leaf areas were greater in winter than in spring in five varieties: in others it changed little. The fresh: dry weight ratios of the leaves were almost constant between varieties in the spring but varied greatly during the winter. Visual colour ratings were well correlated with chlorophyll contents per unit area but not with weight. The net photosynthetic rate was closely correlated with chlorophyll content (per unit area) but not so closely with colour rating.

scholarly journals Simulation of the Time Courses of CO2 Concentration in the Culture Vessel and Net Photosynthetic Rates of Potato Plantlets Cultured Photoautotrophically and Photomixotrophically in Vitro under Different Lighting Cycles

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 515F-515
Author(s):  
Genhua Niu ◽  
Makio Hayashi ◽  
Toyoki Kozai
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Quantitative Relationship ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Ventilation Rate ◽  
Culture Vessel ◽  
Time Courses ◽  
Potato Plantlets

Potato (Solanum tuberosum L. cv. Benimaru) plantlets were cultured under four lighting cycles (photoperiod/dark period: 16 h/8 h, 4 h/2 h, 1 h/0.5 h, and 0.25 h/0.125 h) photoautotrophically (without sugar in the medium), and photomixotrophically (with sugar in the medium) in vitro for 28 days. Simulations of time courses of CO2 concentration in the vessel (Ci) and dry weight accumulation of the plantlets cultured photoautotrophically were conducted using a previously developed model (Niu and Kozai, 1997). While underestimation and overestimation of time courses of Ci in some treatments were observed, the simulated results of Ci and dry weight accumulation of the plantlets generally agreed with the measured ones. The difference of net photosynthetic rate response to Ci throughout the culture period was examined between the plantlets cultured photoautotrophically and photomixotrophically. Quantitative relationship between daily net photosynthetic rate (daily net production) and vessel ventilation rate per plantlet was simulated under various CO2 levels outside the vessel for given sizes of potato plantlets cultured photoautotrophically in vitro to aid appropriate CO2 enrichment and vessel design in commercial micropropagation.

scholarly journals Growth and Net Photosynthetic Rate of Tomato Plantlets during Photoautotrophic and Photomixotrophic Micropropagation

HortScience ◽  
2001 ◽  
Vol 36 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Chieri Kubota ◽  
Natsuko Kakizaki ◽  
Toyoki Kozai ◽  
Koichi Kasahara ◽  
Jun Nemoto
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Dry Weight ◽  
Ventilation Rate ◽  
Photon Flux ◽  
Leaf Removal ◽  
Photosynthetic Photon Flux ◽  
Photoautotrophic Micropropagation ◽  
Number Of Leaves

Nodal explants of tomato (Lycopersicon esculentum Mill.) were cultured in vitro to evaluate the effects of sugar concentration, photosynthetic photon flux (PPF), CO2 concentration, ventilation rate of the vessel, and leaf removal on growth and photosynthesis. After 20 days of culture, the dry weights of plantlets derived from explants with leaves and cultured photoautotrophically (without sugar in the medium) under high PPF, high CO2 concentration, and high ventilation rate were more than twice as great as those of plantlets derived conventionally from explants without leaves and cultured photomixotrophically (with sugar in the medium) under low PPF, low CO2 concentration, and low ventilation rate (107 and 45 mg per plantlet, respectively). Under photomixotrophic micropropagation conditions, the dry weights of plantlets from explants with leaves increased more than did those of plantlets from explants without leaves. High PPF, high CO2 concentration, and high ventilation rate increased net photosynthetic rate and promoted growth of the plantlets under photomixotrophic micropropagation conditions. Photomixotrophic conditions produced the greatest dry weight and the longest shoots, but photoautotrophic conditions produced the highest net photosynthetic rate. The number of leaves did not differ significantly between photoautotrophically and photomixotrophically cultured plantlets. Thus, photoautotrophic micropropagation is applicable to the production of high quality tomato transplants.

scholarly journals Physiological Advantages of Grafted Watermelon (Citrullus lanatus) Seedlings under Low-temperature Storage in Darkness

HortScience ◽  
2011 ◽  
Vol 46 (7) ◽  
pp. 993-996 ◽  
Author(s):  
Ming Ding ◽  
Beibei Bie ◽  
Wu Jiang ◽  
Qingqing Duan ◽  
Hongmei Du ◽  
...  
Keyword(s):  
Low Temperature ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Citrullus Lanatus ◽  
Soluble Sugar ◽  
Photochemical Efficiency ◽  
Chlorophyll Contents ◽  
Low Temperature Storage ◽  
Short Period ◽  
Temperature Storage

Low-temperature storage in darkness is usually used for preserving seedlings for a short period. To investigate whether grafted watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] seedlings are superior to non-grafted ones under low-temperature storage in darkness and to study their physiological differences during storage, watermelon (‘Zaojia 84-24’) scions were grafted to pumpkin (Cucurbita moschata Duch. ‘Zhuangshi’) rootstocks. Carbohydrate levels; chlorophyll and malondialdehyde contents; the activities of superoxide dismutase, catalase, and peroxidase; and photochemical efficiency were assayed during 6 days of storage at 15 °C in darkness. After that, seedlings were transplanted into an artificial climate chamber. The net photosynthetic rate and stomatal conductance (gS) were measured on the first and third days after transplanting. The results showed that the grafted watermelon seedlings had more soluble sugar and chlorophyll contents, higher activities of antioxidant enzymes, and less malondialdehyde content than the non-grafted ones after 6 days of storage. In addition, low-temperature storage in darkness damaged the photosystem II of non-grafted watermelon seedlings more than that of grafted ones. After transplanting, grafted seedlings had a higher net photosynthetic rate. The results suggest that grafted watermelon seedlings were more suitable for the low-temperature storage in darkness than the non-grafted ones.

Amelioration of salinity tolerance in cowpea plants by seed treatment with methyl jasmonate

2017 ◽  
Author(s):  
Omid Sadeghipour
Keyword(s):  
Salt Stress ◽  
Stomatal Conductance ◽  
Methyl Jasmonate ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Nacl Stress ◽  
Soluble Proteins ◽  
Total Soluble Sugars

A pot experiment was conducted to investigate the role of methyl jasmonate (MeJA) in alleviation of the adverse effects of salinity on cowpea. Seeds were soaked in 0, 25 and 50 µM MeJA for 20 h and then the seedlings were irrigated with different concentrations of NaCl (0, 50 and 100 mM). Salt stress markedly decreased growth attributes namely shoot length, shoot and root dry weight and leaf area. NaCl stress also significantly reduced chlorophyll value, stomatal conductance, net photosynthetic rate, total soluble proteins and relative water content (RWC). Furthermore, salinity noticeably increased proline and total soluble sugars content. Nonetheless, seeds treatment with MeJA especially 50 µM, improved the growth of cowpea plants by increasing chlorophyll value, stomatal conductance, net photosynthetic rate, total soluble proteins, proline accumulation, total soluble sugars and RWC under salt stress conditions. Thus results indicate that pretreatment of seeds with MeJA could be used as an effective technique for improving cowpea plants tolerance to salt stress.

scholarly journals Photoautotrophic Micropropagation of Tomato Plantlets

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 515E-515
Author(s):  
C. Kubota ◽  
N. Abe ◽  
T. Kozai ◽  
K. Kasahara ◽  
J. Nemoto
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Dry Weight ◽  
Ventilation Rate ◽  
Culture Conditions ◽  
Culture Period ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Photoautotrophic Micropropagation ◽  
Different Levels

`HanaQueen' tomato plantlets were cultured under conditions with different levels of sugar, photosynthetic photon flux, CO2 concentration, and number of air exchanges of the vessel. Effects of medium substrates (Gelrite or vermiculite) and explant preparation (with or without leaves) on growth of the plantlets were also examined. After 20 days in culture, photoautotrophically cultured plantlets with leafy explants, under increased PPF, CO2, and ventilation rate of the vessel had twice as much dry weight as those cultured conventionally with non-leafy explants under low PPF, CO2, and ventilation rate of the vessel. Dry weight of the plantlets was significantly greater when cultured with leafy than non-leafy explants. Net photosynthetic rate of the plantlets increased linearly as culture period when cultured without sugar, and remained almost zero when cultured with sugar, regardless of other culture conditions. Results obtained in this experiment have shown that tomato plantlets can be grown photoautotrophically, and the net photosynthetic rate was greater under photoautotrophic than under conventional photomixotrophic conditions.

scholarly journals The Effect of Pyraclostrobin Application on Yield of Tea (Camelia sinensis (L.) O. Kuntze) under Wet Season

2019 ◽  
Vol 3 (3) ◽  
pp. 153
Author(s):  
Arief Rahman ◽  
Eka Tarwaca Susila Putra ◽  
Sriyanto Waluyo
Keyword(s):  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Block Design ◽  
Dry Weight ◽  
High Yield ◽  
Fresh Weight ◽  
Wet Season ◽  
Shoot Fresh Weight ◽  
Shoot Dry Weight ◽  
Tea Production

This field experiment aimed to study the effect of pyraclostrobin on tea production and to determine optimum concentration in order to maintain high yield during the period of wet season. The experiment was arranged in Randomized Completely Block Design (RCBD) using single factor and three blocks as replications. The pyraclostrobin doses, consisted of 4 levels, 0, 50, 100, and 150 g.ha-1, each will be tested on three tea clones. Clones tea tested are TRI 2025, Gambung 9 and PGL 15. Data was evaluated for chlorophyll content, photosynthetic rate, number of pecco, number of dormant shoot (banjhi), number of total shoot, pecco fresh weight, banjhi fresh weight, total shoot fresh weight, and shoot dry weight. Data were analysed by using Analysis of Variance (ANOVA) and LSD test at α = 5%. The results informed that pyraclostrobin was able to improve chlorophyll content on TRI 2025 clone, and improved photosynthetic rate on Gambung 9 clone. However,  there was no significant different among plants treated with pyraclostrobin on a yield components, i.e., number of pecco, number of banjhi, pecco fresh weight, banjhi fresh weight, total shoot fresh weight, and total shoot dry weight.

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