scholarly journals Silicon Alleviates Temperature Stresses in Poinsettia by Regulating Stomata, Photosynthesis, and Oxidative Damages

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1419
Author(s):  
Jiangtao Hu ◽  
Yali Li ◽  
Byoung Ryong Jeong

The effects of silicon (Si) on temperature stresses were investigated in poinsettia. Well-rooted cuttings supplemented with and without Si were exposed to 40 °C, and plants treated with or without Si during cutting propagation and cultivation were subjected to 4 °C. The results showed that almost all the stomata of cuttings without Si supplementation were closed, while some of them were still open in cuttings supplemented with Si under a high temperature stress. However, Si was not able to alleviate stomatal closure of poinsettia under low temperature stress. The increased epicuticular wax might contribute to enhanced resistance of poinsettia to low temperature stresses. In addition, poinsettia maintained a higher photosynthetic rate and lower malonaldehyde and hydrogen sulfide concentrations when supplemented with Si under high and low temperature stresses, which might contribute to lower APX activities. Overall, temperature stresses had negative impacts on the physiological characteristics of poinsettia, while Si could alleviate some effects of temperature stresses.

2019 ◽  
Vol 39 (9) ◽  
pp. 1583-1599 ◽  
Author(s):  
Jiazhi Shen ◽  
Dayan Zhang ◽  
Lin Zhou ◽  
Xuzhou Zhang ◽  
Jieren Liao ◽  
...  

Abstract To determine the mechanisms in tea plants responding to temperature stresses (heat and cold), we examined the global transcriptomic and metabolomic profiles of the tea plant cultivar ‘Suchazao’ under moderately low temperature stress (ML), severely low temperature stress (SL), moderately high temperature stress (MH) and severely high temperature stress (SH) using RNA-seq and high performance liquid chromatography tandem mass spectrometry/mass spectrometry (HPLC-MS/MS), respectively. The identified differentially expressed genes indicated that the synthesis of stress-resistance protein might be redirected to cope with the temperature stresses. We found that heat shock protein genes Hsp90 and Hsp70 played more critical roles in tea plants in adapting to thermal stress than cold, while late embryogenesis abundant protein genes (LEA) played a greater role under cold than heat stress, more types of zinc finger genes were induced under cold stress as well. In addition, energy metabolisms were inhibited by SH, SL and ML. Furthermore, the mechanisms of anthocyanin synthesis were different under the cold and heat stresses. Indeed, the CsUGT75C1 gene, encoding UDP-glucose:anthocyanin 5-O-glucosyl transferase, was up-regulated in the SL-treated leaves but down-regulated in SH. Metabolomics analysis also showed that anthocyanin monomer levels increased under SL. These results indicate that the tea plants share certain foundational mechanisms to adjust to both cold and heat stresses. They also developed some specific mechanisms for surviving the cold or heat stresses. Our study provides effective information about the different mechanisms tea plants employ in surviving cold and heat stresses, as well as the different mechanisms of anthocyanin synthesis, which could speed up the genetic breeding of heat- and cold-tolerant tea varieties.


2021 ◽  
Author(s):  
Caihui Wang ◽  
Min Chen ◽  
Bo Liu ◽  
Junhao Ning ◽  
Xia Lu ◽  
...  

Abstract Background: Bohai Red, a new Argopecten scallop strain selected from the hybrids between the Peruvian scallop, Argopecten purpuratus and the bay scallop northern subspecies, A. irradians irradians, is now one of the most cultured scallop strains in northern China. As one of a series of studies focusing on adaptation of Bohai Red scallops to fluctuations in environmental factors, this study aimed to examine the expression profile of Wnt genes in response to different temperature stresses in Bohai Red. Results: As Bohai Red scallops were originated from the hybrids between the Peruvian scallop and the bay scallop northern subspecies, we first identified all Wnt genes from the genomes of the Peruvian scallop and the bay scallop northern subspecies, as well as the bay scallop southern subspecies, A. i. concentricus. Twelve Wnt members were identified from the two subspecies of bay scallop, and 13 Wnt genes were found in the genome of the Peruvian scallop. Protein structure analyses showed that most Wnt genes poses all 5 conserved motifs except Wnt 1, Wnt 2, Wnt 6 and Wnt 9 in the bay scallops and Wnt2 and Wnt9 in the Peruvian scallop. Unexpectedly, Wnt8 gene was present while Wnt3 was absent in both the bay scallops and the Peruvian scallop. Phylogenetic analysis revealed that Wnt3 may have disappeared in the early evolution of mollusks. The expression profile of Wnt genes in Bohai Red exposed to different temperatures were examined by qRT-PCR. The results showed that expression of Wnt genes responded differentially to temperature changes. The Wnt genes such as Wnt1, Wnt6, Wnt7, Wnt11 and WntA that responded slowly to low and high temperature stresses may be related to the maintenance of basic homeostasis. Other Wnt genes such as Wnt4, Wnt9, Wnt5 and Wnt2 that responded rapidly to low temperature may play an important role in organismal protection against low temperature stress. And yet some Wnt genes including Wnt10, Wnt16, and Wnt8 that responded quickly to high temperature stress may play key roles in response to organismal stress provoked by high temperature stress. Conclusions: Wnt genes are well conserved in Argopecten scallops, as in other bivalves. Wnt genes may play important roles in adaptation of Bohai Red scallops to changing temperatures. The results in this study will provide new insights into the evolution and function of Wnt genes in bivalves and eventually benefit culture of Bohai Red scallops.


2019 ◽  
Vol 257 ◽  
pp. 108733 ◽  
Author(s):  
Larissa Húrsula Neves ◽  
Rodolfo Inácio Nunes Santos ◽  
Gabriel Ito dos Santos Teixeira ◽  
Dênmora Gomes de Araujo ◽  
Walter Vellasco Duarte Silvestre ◽  
...  

2021 ◽  
Author(s):  
Peng Zhu ◽  
Jennifer Burney

Abstract. Irrigation has important implications for sustaining global food production, enabling crop water demand to be met even under dry conditions. Added water also cools crop plants through transpiration; irrigation might thus play an important role in a warmer climate by simultaneously moderating water and high temperature stresses. Here we use satellite-derived evapotranspiration estimates, land surface temperature (LST) measurements, and crop phenological stage information from Nebraska maize to quantify how irrigation relieves both water and temperature stresses. Our study shows that, unlike air temperature metrics, satellite-derived LST detects significant irrigation-induced cooling effect, especially during the grain filling period (GFP) of crop growth. This cooling is likely to extend the maize growing season, especially for GFP, likely due to the stronger temperature sensitivity of phenological development during this stage. The analysis also suggests that irrigation not only reduces water and temperature stress but also weakens the response of yield to these stresses. Specifically, temperature stress is significantly weakened for reproductive processes in irrigated crops. The attribution analysis further suggests that water and high temperature stress alleviation contributes to 65 % and 35 % of yield benefit, respectively. Our study underlines the relative importance of high temperature stress alleviation in yield improvement and the necessity of simulating crop surface temperature to better quantify heat stress effects in crop yield models. Finally, untangling irrigation effects on both heat and water stress mitigation has important implications for designing agricultural adaptation strategies under climate change.


Horticulturae ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 112
Author(s):  
T. Casey Barickman ◽  
Omolayo J. Olorunwa ◽  
Akanksha Sehgal ◽  
C. Hunt Walne ◽  
K. Raja Reddy ◽  
...  

Recent evidence suggests that the effects of temperature significantly affect the growth and development of basil plants with detrimental impacts on yield. The current research investigated the interactive effects of varying temperature and CO2 levels on the shoot and root morphology and growth of early and late-season basil plants. Basil plants were subjected to control (30/22 °C), low (20/12 °C), and high (38/30 °C) temperature under ambient (420 μL L−1) and elevated (720 μL L−1) CO2 concentrations. Decreasing the temperature to 20/12 °C caused more adverse effects on the morphological traits of the early-season basil. Relative to the control treatments, low- and high-temperature stresses decreased 71 and 14% in marketable fresh mass, respectively. Basil exhibited an increase in plant height, node and branch numbers, specific leaf area, anthocyanin and nitrogen balance index, root tips, and root crossings when subjected to high-temperature stress. Furthermore, elevated CO2 affected many morphological features compared to ambient CO2 concentrations. The findings of this study suggest that varying the growth temperature of basil plants would more significantly impact the shoot and root morphologies and growth rates of basil than increasing the CO2 concentrations, which ameliorated the adverse impacts of temperature stress.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1072
Author(s):  
T. Casey Barickman ◽  
Omolayo J. Olorunwa ◽  
Akanksha Sehgal ◽  
C. Hunt Walne ◽  
K. Raja Reddy ◽  
...  

Early season sowing is one of the methods for avoiding yield loss for basil due to high temperatures. However, basil could be exposed to sub-optimal temperatures by planting it earlier in the season. Thus, an experiment was conducted that examines how temperature changes and carbon dioxide (CO2) levels affect basil growth, development, and phytonutrient concentrations in a controlled environment. The experiment simulated temperature stress, low (20/12 °C), and high (38/30 °C), under ambient (420 ppm) and elevated (720 ppm) CO2 concentrations. Low-temperature stress prompted the rapid closure of stomata resulting in a 21% decline in net photosynthesis. Chlorophylls and carotenoids decreased when elevated CO2 interacted with low-temperature stress. Basil exhibited an increase in stomatal conductance, intercellular CO2 concentration, apparent quantum yield, maximum photosystem II efficiency, and maximum net photosynthesis rate when subjected to high-temperature stress. Under elevated CO2, increasing the growth temperature from 30/22 °C to 38/30 °C markedly increased the antioxidants content of basil. Taken together, the evidence from this research recommends that varying the growth temperature of basil plants can significantly affect the growth and development rates compared to increasing the CO2 concentrations, which mitigates the adverse effects of temperature stress.


Author(s):  
M. Jincy ◽  
V. Babu Rajendra Prasad ◽  
A. Senthil ◽  
P. Jeyakumar ◽  
N. Manivannan

Background: Drought and high temperature stress limits the crop production. Development of drought and high temperature tolerant cultivars that can withstand and yield better under adverse conditions is very much important to ensure the food and nutritional security. Green gram is one of the important pulse crops with high nutritional and economic value. Among the various stages of plant growth and development, reproductive stage is highly sensitive to drought and high temperature stress across all species. The main objective of this study was to evaluate green gram germplasm collection and identification of elite greengram genotypes that can withstand drought and high temperature stresses at reproductive stage. Methods: The experiment was conducted during March-April, 2019, at National Pulses Research Centre, Vamban, Pudukottai district, Tamil Nadu. To study the influence of combined drought and high temperature stress during reproductive stage, the green gram genotypes were sown in pots. Six pots were maintained for each genotype of which three were maintained at 100% field capacity (control) and for another three; drought stress (50% field capacity for 5 days) was imposed combined with high temperature stress (36 ± 2°C) during reproductive phase (35 Days after sowing). At the end of stress period, physiological and biochemical analysis were carried out to identify the tolerant green gram genotypes against drought and high temperature stresses.Result: In the present study, drought and high temperature stress has negative impact on green gram physiology. Among the genotypes screened for their tolerance at reproductive stage, the following green gram genotypes viz., TARM 1, VGG 15029, VGG 17003, VGG 17004, VGG 17006, VGG 17010 and VGG 17019 were found to withstand drought and high temperature stress and maintain high total chlorophyll content, relative water content and chlorophyll stability index. These green gram gramplasm can be used in pulse breeding program to evolve resilient green gram varieties. Screening of 29 green gram genotypes for drought and high temperature stress during reproductive stage were carried out by maintaining the drought stress (50% field capacity for 5 days) combined with high temperature stress (36 ± 2°C) during reproductive stage (35 days after sowing) by pot culture experiment. Total chlorophyll, relative water content, chlorophyll stability index (CSI), oxidants and antioxidant activity were quantified to identify the tolerant green gram genotypes against drought and high temperature stresses. Based on physiological and biochemical parameters, the following green gram genotypes viz., TARM 1, VGG 15029, VGG 17003, VGG 17004, VGG 17006, VGG 17010 and VGG 17019 were found to withstand and tolerate combined drought and high temperature stresses at flowering stage.


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