Short-term High Temperature Stress Research Articles

Light intensity influences the glycerolipid remodeling of Gracilariopsis lemaneiformis in response to short-term high temperature stress

Temperature and light are two pivotal environmental factors for the growth of marine photosynthetic organisms. While the responses of Gracilariopsis lemaneiformis to individual high temperature or light stress have been explored, our understanding of its combined stress responses remains limited. This study aimed to investigate the combined effects of short-term high temperature (33 °C, 8 h) and different light intensities, that is, low light (LL, 50 μmol photon m−2 s−1), medium light (ML, 150 μmol photon m−2 s−1), and high light (HL, 300 μmol photon m−2 s−1), on the physiological responses and lipid remodeling of G. lemaneiformis. Results demonstrated that short-term exposure to either high temperature or high light stress led to a reduction in maximum (Fv/Fm), effective photochemical efficiency (Fv'/Fm') and maximum relative electron transfer rate (rETRmax), and the combination of these stresses exerted a more pronounced inhibitory effect on photosystem II efficiency. Short-term exposure to heat stress led to an increase in superoxide dismutase (SOD) activity, as well as a rise in glutathione (GSH) and ascorbate (Asc) contents under LL, while the activities of antioxidant enzymes (SOD, peroxidase, and ascorbate peroxidase) and levels of non-enzymatic antioxidants (GSH and Asc) were reduced under ML and HL. Additionally, short-term heat stress induced the accumulations of phosphatidylcholine (PC), phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol, sulfoquinovosyldiacylglycerol, and triacylglycerol (TAG) under LL, while heat-induced lipid accumulation decreased under ML and HL. Furthermore, heat stress increased the accumulation of saturated or unsaturated PC species under LL. Specifically, there was an increase in the levels of saturated or monounsaturated acyl chain–containing PC species, whereas the levels of polyunsaturated acyl chain-containing PC species declined under ML and HL. Correspondingly, a significant increase in TAG species with polyunsaturated acyl chains was observed, particularly under LL conditions, suggesting a potential lipid turnover between PC and TAG. These results showed that the lipid metabolic plasticity of G. lemaneiformis enabled it to rapidly adapt to fluctuating environmental conditions, and the light environment regulated its heat stress response.

Yield compensation among plant regions improves soybean adaptation to short-term high-temperature stress during the reproductive period

Extreme heat events prolong the reproductive period and threaten soybean yield, whereas the specific stage at which individual fruits growth is delayed, and yield/yield components at the node, region, and plant levels under short-term heat stress in the reproductive stage are elusive. In this study, heat treatments (40/30 °C) were applied at 0–6 days (HTF0-6), 6–12 days (HTF6-12), 12–18 days (HTF12-18), and 0–12 days (HTF0-12) after the plant's first flower opened, and a control treatment (32/22 °C) was performed. The influences of heat stress on fruit development and yield/yield components at the node, region, and plant levels were investigated. As a result, the growth of individual fruits at nodes was delayed by HTF0-6 and HTF0-12, which was primarily caused by the prolongation of flowering to pods with a length of 2 cm. Interestingly, there were no significant differences in yield between the control treatment and the various high-temperature stress treatments at the plant level. Further analysis of the regional yield of soybean showed that the yield in the bottom and top regions of plants played significant roles in compensating for yield loss in the middle region after HTF0-12. Moreover, the delayed growth of individual fruits in the middle region was negatively correlated with yield. Our results indicate that the prolongation of fruit development induced by HTF0-6 and HTF0-12 may adversely affect soybean yield. However, the spatial compensation of plants could help maintain soybean yield under various short-term high temperature stress treatments during the reproductive period, which should be considered when breeding for and selecting heat-tolerant varieties.

Long-term high temperature stress decreases the photosynthetic capacity and induces irreversible damage in chrysanthemum seedlings

To study the effects of long-term and short-term high temperature stress and recovery on the physiological functions and appearance quality of chrysanthemums, a controlled experiment with chrysanthemums was conducted. The treatments were 25 °C for 3 days (T1D3), 25 °C for 9 days (T1D9), 41 °C for 3 days (T2D3) and 41°C for 9 days (T2D9). The results indicated that there is no significant difference between the T1D3 and T1D9 groups. Conversely, the total chlorophyll content (Chl), net photosynthetic rate (PN), and maximum quantum yield of Photosystem II (PSII) (FV/FM) under T2D3 and T2D9 decreased by 27.07%, 43.30%, 5.62%, and 44.85%, 68.22%, 8.29%, respectively. The JIP-test results showed that the T2D9-stressed plants had a lower efficiency and functional antenna size, and a higher activity of the reaction centre than T2D3. The contents of malondialdehyde, soluble protein and proline increased by 3.67 nmol/g FM, 298.75 μg/g, and 192.99 μg/g, and the antioxidant enzymes activities were inhibited significantly under T2D9. After the stress was relieved, Chl, PN, and FV/FM under T2D3 recovered to the same level as T1D3, while T2D9 did not. Furthermore, the diameter of the flowers in T2D3 showed no significant difference with the chrysanthemums under T1D3. However, the plants in T2D9 recovered poorly. Both the diameter of the flowers and the anthocyanin under T2D9 reduced significantly comparing with T1D9, indicating that the damage in the chrysanthemum seedlings caused by long-term high temperature was irreversible.

Effects of short-term heat stress on the performance of the predatory gall midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae)

ABSTRACT Aphidoletes aphidimyza is one of the most important natural enemies of aphids, but its efficiency in aphid control is affected by temperatures. We measured the life history parameters of A. aphidimyza by exposing its different life stages to 35°C for 3, 6, and 12 h. The results showed that the survival rate of eggs, first instar larvae, pupae, and mated males was decreased significantly with the increase of the exposure duration, whereas the survival rate of third instar larvae and adult females was not significant different before and after the exposure. The short-term high temperature stress also significantly decreased the predation of first and second instar larvae, whereas the predation of third instar larvae was not affected. In addition, the heat stress did not affect adult egg production, longevity, and offspring hatching rates, regardless of mating status. These results demonstrated that short periods of heat stress negatively influenced A. aphidimyza development, but the effect was dependent on duration and developmental stage. Therefore, in order to achieve the best predatory efficacy of gall midges against aphid pests, the heat stresses above 35°C should be avoided.

Multigenerational Effects of Short-Term High Temperature on the Development and Reproduction of the Zeugodacus cucurbitae (Coquillett, 1899)

Zeugodacus cucurbitae is an important pest of fruit and vegetable crops in tropical and subtropical regions, and high-temperature stress can have different effects on the development and reproduction of successive generations of Z. cucurbitae. To clarify the multigenerational effects of short-time high temperature on the development and reproduction of Z. cucurbitae, the newly emerged adults of the contemporary (F1 generation) and the next generation (F2 generation) were exposed to short-term high temperatures of 25 °C, 33 °C, 37 °C, 41 °C, and 45 °C for 1 h, and the multigenerational (F1, F2, and F3 generation) effects of these temperatures on the development and reproduction of Z. cucurbitae were evaluated. The results showed that (1) when the F1 was exposed to short-term high temperature, the egg production and lifespan of the F1 decreased continuously with the increasing temperature, except for the 45 °C treatment for 1 h, which stimulated egg production. Only the 41 °C group had significantly higher egg production and lifespan than the control group in the F3. (2) In the F1 and F2 that were exposed to short-term high temperature, the F1 and F3 were consistent with the results of F1 that were exposed to short-term high temperature. In conclusion, the effects of high-temperature intensity and frequency on multiple generations of Z. cucurbitae were different. The results of this study can elucidate the effects of short-term high-temperature stress on the growth, development, and reproduction of Z. cucurbitae in different generations, and provide a reference basis for the integrated control of Z. cucurbitae.

Dynamic expression analysis of Vitelloin-related genes in Zeugodacus cucurbitae (Coquillett) driven by short-term high-temperature stress.

Zeugodacus cucurbitae (Coquillett) is an important pest of fruit and vegetable crops in tropical and subtropical regions. Previous studies have shown that short-term high-temperature stress has a significant effect on the oviposition behavior of three successive generations (F1 -F3 ) of Z. cucurbitae (Coquillett). For the clarification of the molecular response of the oviposition behavior of Z. cucurbitae (Coquillett) to short-term high-temperature stress, three Vitellogenin (Vg) genes, namely, Vg-1, Vg-2, and Vg-3, and one Vitellogenin receptor (VgR) gene were selected; 25°C was used as the control treatment; and 33°C, 37°C, 41°C, and 45°C were set as the high-temperature treatments. Newly emerged adults of the F1 generation were treated for 1 h, and the expression dynamics of the target genes were analyzed 7 days after the emergence of three successive generations of adults. Results showed that the expression of the Vg gene in the 33°Cand 37°C groups was upregulated compared with that in the control group, and the difference among the 41°C, 45°C, and control groups was small. VgR gene expression level gradually increased in each treatment group with the increase in the number of days and peaked on Days 6 and 7. Compared with the control group, the expression of VgR gene in the F1 generation was downregulated in the high-temperature treatment group over 7 days. On Day 7, the expression level of the VgR gene in the F2 and F3 generations in the 37°Cand 45°C groups was significantly higher than that in the F2 and F3 generations in the control group. In conclusion, Vg and VgR are transformed and utilized differently after short-term high-temperature treatment.

Effect of short-term high temperature on the accumulation of glucosinolates in Brassica rapa

Glucosinolates, an important class of secondary metabolites in cruciferous vegetables, play a crucial role in protecting plants from stress-related damage. The mechanism of glucosinolate synthesis under short-term high temperature stress has not been sufficiently studied. In this work, we investigated the changes in transcription factors, synthetic genes, and related metabolites involved in glucosinolate synthesis by pakchoi seedlings under short-term high temperature stress (40 °C for 8 h). Short-term high temperature stress inhibited the primary sulfur assimilation and the contents of methionine, cysteine and glutathione. The contents of aliphatic and indolic glucosinolates were increased by short-term high temperature stress, whereas the content of 4-methoxy-glucobrassicin increased significantly. During the stress period, the transcript level of glucosinolate related MYB transcription factors had been basically significantly up-regulated, whereas the transcript level of aliphatic and indolic glucosinolate synthetic genes were predominantly up-regulated and down-regulated respectively. In the early recovery period, primary sulfur assimilation up-regulated rapidly, and decreased during the late recovery process. The glucosinolate content and synthesis gene expression act similar to the primary sulfur assimilation, a short up-regulated in early recovery, then all go down at 40 and 48 h after short-term high temperature treatment.

Response Mechanism of Oviposition and Relevant Protein Expression of Bactrocera cucurbitae (Coquillet) to Short-Term High-Temperature Conditions.

Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) is an important pest of vegetables in Asia, the Middle East, Africa, and Hawaii. High temperature can significantly influence B. cucurbitae reproduction. The effect of short-term high-temperature exposure on proteins that affect oviposition was analyzed by proteomics. Among six key target genes for oviposition, the expression of Vitellogenin-1, Vitellogenin-2, and Vitellogenin receptor was similar in B. cucurbitae exposed to higher temperature compared to controls. However, levels of Vitellogenin-3 were reduced. Juvenile hormone (Jh)-inducible protein was downregulated and then upregulated, while the expression of Jh-epoxide hydrolase-2 showed the opposite Jh-inducible protein trend. Therefore, short-term high-temperature stress can cause differential expression of proteins related to oviposition in B. cucurbitae, which in turn further triggers the hormesis of oviposition. High-temperature conditions have become more frequent because of climate warming and are predicted to continue. The data indicate that climate effects on insect reproduction pose a significant threat to agriculture in a world of increasing population.

Effects of zinc fertilizer and short-term high temperature stress on wheat grain production and wheat flour proteins

Content of wheat flour proteins affects the quality of wheat flour. Zinc nutrition in wheat can change the protein content of the flour. The inconsistency and instability of wheat grain quality during grain filling while under high temperature stress (HTS) are major problems in the production of high quality wheat. At present, there is a lack of studies on zinc fertilizer and HTS effects on wheat flour protein and the content of its components. For this study, treatment combinations of four levels of zinc fertilizers and exposure to a short-term HTS, at 20 d after flowering (D20), were tested on two wheat cultivars with different gluten levels. Individuals of a strong gluten wheat, Gaoyou 2018 (GY2018), and a medium gluten wheat, Zhongmai 8 (ZM8), were grown in pots at the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing in 2015–2017. We measured grain yield and weight and the activities of two enzymes (nitrate reductase and glutamine synthetase) from the flag leaves, collected at D10 and D20. Total protein content, protein yield, and content of four protein components (albumin, gliadin, glutenin, and globulin) were measured from flour produced from the pot-grown plants. HTS significantly increased the contents of total protein, albumin, gliadin, and glutenin in wheat grains, and reduced the grain yield, grain weight, protein yield, globulin content, and flag leaf nitrate reductase (NR) and glutamine synthetase (GS) activities. The results showed that HTS and zinc fertilizer had greater impacts on the strong gluten cultivar compared to the medium gluten cultivar. Under HTS, grain yield decreased by 13 and 8% in GY2018 and ZM8, respectively; protein yield decreased by 7 and 8% in GY2018 and ZM8, respectively. Zinc fertilizer increased: grain and protein yields; grain weight; total protein, albumin, gliadin, and glutenin contents; protein yield; and NR and GS activities. In contrast, zinc fertilizer reduced the content of globulin. The addition of 15 mg Zn kg–1 soil had the strongest effect on grain yield and quality as compared to the other three treatments (additions of 0, 30, and 45 mg Zn kg–1 soil). Zinc fertilizer also reduced the negative effects of HTS on protein yield, content, and components’ content. Therefore, wheat grown with additional zinc in the soil can improve the quality of the flour.

Anatomically distinct representatives of Cactaceae Juss. family have different response to acute heat shock stress

In order to escape extreme environmental conditions plants have developed different survival strategies. The study of plant response to high temperatures is especially interesting in representatives of varied cacti families that have to resist big temperature oscillations. In the present study plants of Aylostera, Echinocactus and Mammillaria genera were exposed to temperatures of 40 or 50 °C for 3 h and peroxidase and superoxide dismutase activity, photosynthetic pigments and flavonoids concentration, and lipid peroxide oxidation level in the stem were determined. Plants with different anatomical structure showed distinct patterns of response to high temperature. Plants of Echinocactus grusonii proved the highest drought and heat resistant with strong antioxidant response and the most expressed xerophytic features of anatomical structures (epidermis and cuticle thickening, calcium oxalate accumulation, water-storage tissue development). Heat stress induced a quick increase of peroxidase activity and flavonoid concentration in this species. Relative heat resistance (40 °C) in Mammillaria bocasana is also facilitated by increased flavonoid concentration, chlorophyll a and carotenoid concentration and also high superoxide dismutase activity under normal conditions.We conclude that the development of antioxidant reactions depends on anatomical protection of plants. More effective anatomical conformation to the stress conditions may be accompanied by rapid response to stress at the antioxidant biochemical level. Less effective protection at the anatomical level to hyperthermia is accompanied by the presence of a larger activity of antioxidant enzymes in conditions without short-term high-temperature stress. Plants which do not possess these qualities, Aylostera flavistyla in particular, suffer more from short-term high-temperature stress.

Effects of sulfur fertilization and short-term high temperature on wheat grain production and wheat flour proteins

The content of wheat flour proteins affects the quality of wheat flour. Sulfur nutrition in wheat can change the protein content of the flour. The inconsistency and instability of wheat grain quality during grain filling under high temperature stress (HTS) are a major challenge to the production of high-quality wheat. The effects of sulfur fertilization and HTS on wheat flour protein and its components are unknown. In this study, treatments varying two factors: sulfur fertilization and exposure to short-term HTS, at 20days post-anthesis, were applied to two wheat cultivars with differing gluten types. Plants of a strong-gluten wheat (Gaoyou 2018) and a medium-gluten wheat (Zhongmai 8) were grown in pots in Beijing in 2015–2017. HTS significantly increased the contents of total protein, albumin, gliadin, glutenin, Cys, and Met in wheat kernels, but reduced grain yield, grain weight, protein yield, globulin content, and total starch accumulation. The HTS-induced increase in total protein amount was closely associated with nitrate reductase (NR) and glutamine synthetase (GS) activities in flag leaves. Sulfur fertilization increased grain and protein yields; grain weight; total protein, albumin, gliadin, glutenin, and globulin contents; protein yield; total starch; Cys, Met; and NR and GS activities. HTS and sulfur fertilization had larger effects on the strong- than on the medium-gluten cultivar. Sulfur fertilization also alleviated the negative effects of HTS on grain yield, protein yield, and starch content. Thus, growing wheat with additional soil sulfur can improve the quality of the flour.

Susceptible time window and endurable duration of cotton fiber development to high temperature stress

The development of the cotton fiber is very sensitive to temperature variation, and high temperature stress often causes reduced fiber yield and fiber quality. Short-term high temperature stress often occurs during cotton production, but little is known about the specific timing and duration of stress that affects fiber development. To make this clear, pot experiments were carried in 2014 and 2015 in a climate chamber using cotton cultivars HY370WR (less sensitive variety) and Sumian 15 (heat sensitive variety), which present different temperature sensitivities. Changes of the most important fiber quality indices (i.e., fiber length, fiber strength and marcironaire) and three very important fiber development components (i.e., cellulose, sucrose and callose) were analyzed to define the time window and critical duration to the high temperature stress at 34°C (max38°C/min30°C). When developing bolls were subjected to 5 days of high temperature stress at different days post-anthesis (DPA), the changes (Δ%) of fiber length, strength and micronire, as a function of imposed time followed square polynomial eq. as y=a+bx+cx2, and the time around 15 DPA was the most sensitive period for fiber quality development in response to heat stress. When 15 DPA bolls were heat-stressed for different durations (2, 3, 4, 5, 6, 7 days), the changes (Δ%) of fiber length, strength and micronire, as a function of stress duration followed logistic equations y=A1-A21+(X/X0)p+A2. Referred to that 5, 10 and 15% are usually used as criteria to decide whether techniques are effective or changes are significant in crop culture practice and reguard to the fiber quality indices change range, we suggested that 5% changes of the major fiber quality indices (fiber length, fiber strength and micronaire) and 10% changes of fiber development components (cellulose, sucrose and callose) could be taken as criteria to judge whether fiber development and fiber quality have been significantly affected by high temperature stress. The key time window for cotton fiber development in response to the high temperature stress was 13–19 DPA, and the critical duration was about 5 days.

A Comparative Study of Survival, Metabolism, Immune Indicators, and Proteomics, in Five Batches of Japanese Scallop Mizuhopecten yessoensis under Short-Term High Temperature Stress

Five batches of the Japanese scallop Mizuhopecten pyessoensis were tested for survival rate, oxygen consumption, catalase (CAT) and superoxide dismutase (SOD) activities, total antioxidant capacities (T-AOC) contents, and proteomics under short-term high temperature conditions. The five batches, (W1, W2, W3, W4, W5) selected from the established 21 ‘ivory white’ M. yessoensis batches, had higher survival rates than the other batches after one year of culture. Initial rearing water temperature of 15°C was increased by 1°C per day with a cooling and heating system. The temperature was raised until over 50% of the scallops from 3 batches died. This occurred at 30°C. The higher than normal culture temperature conditions showed significant or highly significant differences in the responses of some of the batches. Some showed significantly higher survival rates and significantly different rates of oxygen consumption. CAT activity, SOD activity and T-AOC content was similar in the five batches, and all three indices were significantly lower in W3 and W5 than in the other batches (P<0.01). Expression patterns of MDA content were opposite to those of CAT activity, SOD activity and T-AOC content. Protein profiles of all five batches were similar; the sizes of the predominant bands ranged from 20-110 kDa. We identified twenty-eight proteins with high scores in the database. These included heat shock proteins (HSPs), glucose-regulated protein 94, and arginine kinase.

不同温度下CO2浓度增高对坛紫菜生长和叶绿素荧光特性的影响

Atmospheric CO 2 concentration is predicted to nearly double by the end of this century.There are a large number of reports on the effects of elevated atmospheric CO 2 concentrations on seaweeds.However,the investigation concerning the impacts of combined effects of elevated atmospheric CO 2 concentrations and temperature on seaweeds is very limited.In the present study,the red seaweed Porphyra haitanensis(Bangiales,Rhodophyta) was cultured under four different conditions:(1) 15 ℃ + 390μmol/mol CO 2,(2) 15 ℃ + 700μmol/mol CO 2,(3) 25 ℃ + 390μmol/mol CO 2,(4) 25 ℃ + 700μmol /mol CO 2,in order to examine the combined effects of the elevated CO 2 concentrations and temperature on growth,some biochemical components and chlorophyll fluorescence in this commercially important species.The results indicated that the growth response of P.haitanensis to elevated CO 2 in seawater was temperature dependent,with the enhancement of growth resulting from elevated CO 2 being remarkable greater at lower growth temperature(15 ℃) with respect to 25 ℃.The CO 2 conditions in culture exerted a much pronounced influence on the contents of Chlorophyll a(Chl a) and Carotenoid(Car) than temperature did.15 ℃-grown P.haitanensis exhibited much higher maximum relative electron transport rate(rETR max) in comparison with 25 ℃-grown thalli,regardless of the CO 2 concentrations in culture.This indicated that P.haitanensis displayed a higher photosynthetic potential at low growth temperature than high growth temperature.Meanwhile,extra CO 2 in the culture had no significant impact on rETR max in P.haitanensis.The characters of chlorophyll fluorescence were determined under different measurement temperatures using Junior-PAM.The increase of measurement temperature from 10 to 30 ℃ made a negligible effect on rETR max,the photosynthetic light use efficiency of electron transport(α,the initial slope of the rapid light curves) and maximum photochemical quantum yield values(F v / F m),regardless of the growth conditions.However,the values of rETR max 、α and F v / F m were reduced drastically when the measurement temperatures were above 30 ℃,with the decline being much pronounced in 15 ℃-grown algae than 25 ℃-grown algae.Our results suggested that high temperatures(30—40 ℃) in the short-term inhibited the photosynthetic capacity of P.haitanensis,which might be associated with the damage in photosystem Ⅱ(PSⅡ) reaction centre and a concomitant reduction of electrons transport rate.Meanwhile,25 ℃-grown algae showed a higher tolerance to high temperature stress than 15 ℃-grown algae did,since 15 ℃-grown algae displayed greater downtrend in the values of rETR max 、α and F v / F m when the measurement temperatures rose to 30 ℃.The results also showed that the value of rETR max was lower in P.haitanensis thalli grown under CO 2 enriched air with respect to non-enriched air when the algae were subjected to the high temperatures,indicating that,compared to normal CO 2 growth conditions,elevated CO 2 growth conditions might repress the ability of photosynthetic electron transport of algae when subjected to short-term high temperature stress.

Effect of short-term high temperature stress on the development and fecundity of Ophraella communa (Coleoptera: Chrysomelidae)

Since insects are ectothermic, they are highly vulnerable to the sudden increase of temperature. Indeed, it has been hypothesized that the survival, development, fecundity, and even population expansion of insects are all affected significantly by extremely high temperature. We studied the effect of short-term high temperature stress on the survival and development of different stages, adult longevity and fecundity of Ophraella communa (Coleoptera: Chrysomelidae), a biological control agent of the invasive plant, the common ragweed, Ambrosia artemisiifolia (Asterales: Asteraceae) in the laboratory. The results showed that egg, larval, pupal and adult survival rates were significantly affected after 2 hour-short-stress at high temperatures (35 to 47°C) when compared to the 28°C control. With the exceptions of the control and 35°C stress, survival rate of females was significantly higher than that of males after short-stress at any high temperature. Short-term high temperature stress also significantly impacted longevity and fecundity of adult beetles. Except for control, female longevity was significantly longer than male's after short-stress at any high temperature. The survival rates of different stages, and adult longevity and fecundity of the beetle decreased significantly with the increase of short-term stress temperature. Based on the results of the present study, we conclude that the development and population expansion of O. communa may be significantly affected when they are exposed to a high temperature stage in a summer day in the areas invaded by common ragweed, in southern China.