Explore the vast range of titles available.

Neotoxoptera formosana is an allium vegetable pest that has increasingly threatened Chinese leek production in North China in recent years. The effects of temperature on the biological characteristics and physiology of N. formosana are not well understood. In this study, life tables were constructed at 12 °C, 16 °C, 20 °C, 24 °C, and 28 °C to explore the effects of temperature on the development, reproduction, and population dynamics of N. formosana, and to determine the threshold temperature (C) and the effective cumulative temperature (K) for each developmental stage of this aphid. The protective enzyme activity of N. formosana at three representative temperatures, 12 °C, 20 °C, and 28 °C, was determined to explore the physiological response of N. formosana to temperature. The result showed that the increasing temperature speeded up the development of N. formosana, but decreased the body size, and shortened the longevity and reproduction period of adults. The temperature exceeding 20 °C inhibited its reproduction. The N. formosana population was obviously inhibited by 28 °C with all the population parameters decreasing to be the lowest, especially the fecundity, which was 16.7 times lower than that at 20 °C. The population expanded the fastest at 20 °C, followed by 24 °C, 16 °C, and 12 °C, the slowest at 28 °C, with the population size merely increasing to 2.3 times at 60 days. The K values for the first, second, third, and fourth-instar nymphs were 1.852 °C, 5.029 °C, 4.747 °C and 5.979 °C, respectively, and the C values were 47.540 days °C, 30.817 days °C, 33.481 days °C and 32.294 days °C, respectively. The C value for nymphal aphids was 4.002 °C, and the K value was 145.252 days °C. The activity of superoxide dismutase and peroxidase of N. formosana at 28 °C was higher than at 12 °C and 20 °C, and the catalase activity of N. formosana was highest at 12 °C. In conclusion, the temperature had significant effects on population parameters and the physiological metabolism of N. formosana.

To investigate the effects of low-temperature (LT) stress on photosynthetic properties and senescence characteristics of winter wheat leaves during the jointing stage, an environmental temperature control experiment was designed at Nanjing University of Information Science and Technology in 2023, using Triticum aestivum L. cv. “Ji Mai 22” as the test material. Four different temperature levels were set: 18 °C/8 °C (daily maximum/daily minimum temperature; CK), 13 °C/3 °C, 10 °C/0 °C, and 7 °C/3 °C. The duration of each treatment was 2, 4, and 6 days, respectively. The experimental findings reveal that the changes in physiological parameters of winter wheat leaves under low-temperature stress treatments are nonlinear. Under the 3 °C LT treatment, the photosynthetic parameters and endogenous hormone levels of wheat leaves significantly decrease after 6 days of stress. Under the 0 °C LT treatment, the photosynthetic parameters, leaf pigment content, and endogenous hormones of wheat decrease significantly, while under the −3 °C LT treatment, all the parameters of winter wheat leaves show a significant decline. Generally, the “Ji Mai22” wheat cultivar has a lower growth temperature limit of −3 °C during the jointing stage.

(1) Objective: To investigate the chemical defense response mechanisms of two cotton (Gossypium hirsutum L., Malvaceae) varieties, Xinlu Zhong 57 and Xinlu Zhong 78, in response to feeding by the cotton aphid (Aphis gossypii Glover, 1877) (Hemiptera: Aphididae) in the Kashi region. (2) Methods: The artificial infestation method was adopted to determine the dynamic changes in the contents of secondary metabolites (tannins, total phenols), activities of protective enzymes (SOD, POD, PPO), and contents of nutrients (soluble sugars, amino acids) in cotton leaves at 0, 24, 48, 72, and 96 h after infestation with cotton aphids. (3) Results: The contents of secondary metabolites and the activities of protective enzymes in both varieties showed an initial increase followed by a decrease. The response of Xinlu Zhong 57 was earlier and stronger. Its tannin and total phenol contents reached a peak at 48 h, with values of 264.2 nmol/g and 5.973 mg/g, respectively, which were significantly higher than those of Xinlu Zhong 78 (p < 0.05). The activities of SOD, POD, and PPO were consistently higher in Xinlu Zhong 57. At 48 h post-inoculation, SOD activity in Xinlu Zhong 57 was 238.1 U/g, significantly higher than in Xinlu Zhong 78 (p < 0.05). POD activity was 49.0 U/g, and PPO activity was 94.5 U/g, both significantly higher than those of Xinlu Zhong 78 (p < 0.05). This suggests that Xinlu Zhong 57 has a stronger ability to scavenge reactive oxygen species. Regarding nutrients, soluble sugar content in Xinlu Zhong 57 was 6.99 mg/g at 96 h, significantly higher than that in Xinlu Zhong 78 (p < 0.05). The amino acid content at 96 h was 224.4 μg/g, also significantly higher than in Xinlu Zhong 78 (p < 0.05). (4) Conclusions: Xinlu Zhong 57 forms a more effective chemical defense system by rapidly activating the defense enzyme system, efficiently accumulating secondary metabolites, and optimizing nutrient allocation. This study provides a theoretical basis for elucidating the physiological mechanisms of cotton resistance induced by cotton aphids by analyzing the effects of cotton aphid stress on the contents of secondary metabolites, protective enzyme activities, and nutrient contents in cotton leaves.

Water shortages and crop responses to drought and salt stress are related to the efficient use of water resources and are closely related to food security. In addition, PEG or NaCl stress alone affect the root hydraulic conductivity (Lpr). However, the effects of combined PEG and NaCl stress on Lpr and the differences among wheat varieties are unknown. We investigated the effects of combined PEG and NaCl stress on the root parameters, nitrogen (N) and carbon content, antioxidant enzymes, osmotic adjustment, changes in sodium and potassium, and root hydraulic conductivity of Yannong 1212, Heng 4399, and Xinmai 19. PEG and NaCl stress appreciably decreased the root length (RL), root surface area (RS), root volume (RV), K+ and N content in shoots and roots, and Lpr of the three wheat varieties, while the antioxidant enzyme activity, malondialdehyde (MDA), osmotic adjustment, nonstructural carbon and Na+ content in shoots and roots, etc., remarkably remained increased. Furthermore, the root hydraulic conductivity had the greatest positive association with traits such as RL, RS, and N and K+ content in the shoots of the three wheat varieties. Moreover, the RL/RS directly and actively determined the Lpr, and it had an extremely positive effect on the N content in the shoots of wheat seedlings. Collectively, most of the root characteristics in the wheat seedlings decreased under stress conditions, resulting in a reduction in Lpr. As a result, the ability to transport nutrients—especially N—from the roots to the shoots was affected. Therefore, our study provides a novel insight into the physiological mechanisms of Lpr.

Aegilops tauschii Coss., an invasive weed, has a detrimental impact on the winter wheat cultivation areas of China. Understanding how drought influences competitive ability of A. tauschii can help identify traits related to its invasiveness and guide management. Slight, moderate, and severe soil drought stress conditions were established using potted weighing and water control methods. Concurrently, the de Wit replacement experiment was conducted to assess changes in morphological structure, biomass allocation, and physiological characteristics under varying intensities of soil drought stress. Based on observations of alterations in plant height, total leaf area, and total biomass, two-factor variance analysis revealed that soil drought inhibited the growth and development of both A. tauschii and Triticum aestivum L. (‘Xinmai 32’). Furthermore, one-factor variance analysis revealed that A. tauschii and wheat responded to soil drought stress by increasing superoxide dismutase (SOD) activity and proline content. However, as drought severity escalated, chlorophyll content in A. tauschii and wheat declined significantly, while relative electrical conductivity (REC) and thiobarbituric acid (TBA) content increased markedly. The results of the fuzzy membership function indicated that A. tauschii exhibited greater drought tolerance compared to the tested wheat variety. Lastly, considering adjustments in the corrected index of relative competition intensity (CRCI), it was observed that soil drought amplified the competitive inhibition of A. tauschii on wheat. In short, A. tauschii was more tolerant of the soil drought stress than wheat through the favorable adjustment of morphology, biomass allocation pattern and physiological features, and soil drought intensified its competitive inhibition on wheat.

The research results of the growth-promoting effects of endophytic bacteria on Phyllostachys edulis indicated that the growth-promoting endophytic bacteria could improve photosynthesis in P. edulis leaves. The photosynthetic rate, transpiration rate, and the stomatal conductance in P. edulis treated with endophytic bacteria were all higher than in the control group. Endophytic bacteria could also increase the chlorophyll content and the protective enzyme activities in P. edulis, improving their reactions to the adverse environmental conditions. Through injection treatments with growth-promoting endophytic bacteria, the catalase, superoxide dismutase (SOD), peroxidase activity, soluble protein content, and soluble sugar content in P. edulis were all higher than in the control group, except for the malondialdehyde content, which was lower than in the control group.

ABSTRACT Ectropis grisescens Warren 1894 is a tea garden pest that poses a significant threat to tea yield and quality. To better understand its ecological resilience and potential population dynamics under changing environmental conditions, this study investigated the tolerance of E. grisescens to low temperatures and the consequent effects on its survival, reproduction, and protective enzyme activities. The experimental treatments of a control of 25°C and eight low temperature treatments (-8,-5, 0, 5, 10, 15 and 20°C for 1 h and-10°C for 10 min) were set. Assessment of parameters, including male adult longevity, eggs laying number, egg hatching rate, total protein content, and activities of key antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and total antioxidant capacity (T-AOC) were measured. In the results, as the temperature decreased, the lifespan of both female and male E. grisescens adults shortened. At-10°C, the survival periods for females and male adults were only 1.67 and 1.47 days, respectively. Similarly, fecundity was significant impacted, the number of eggs laid and hatching rate gradually decreased with decreasing temperature, eggs laid by per female on average reached only 118.60 with a hatching rate of 0% at-10°C. Moreover, the total protein content reached its highest level in female adults (7435.58 µg mg-1) at 15°C while in males (3790.29 µg mg-1) at-8°C. The SOD activity in female adults peaked at-10°C (18.56 U mgprot-1), while that in male adults peaked at 10°C (6.58 U mgprot-1), both significantly higher than other treatments. The CAT activity was higher in female adults compared to male adults, with decreasing temperature, the CAT activity decreased in female adults while that increased in male adults. The POD activity reached its peak at-10°C for both female (0.43 U mgprot-1) and male (0.84 U mgprot-1) adults. The T-AOC content was highest in the control group compared to other treatments. These findings on the changes of protective enzyme activities in E. grisescens indicated their important role in adapting to low temperature stress. The study provides a theoretical basis for predicting the development of E. grisescens population under low temperature.

Keteleeria fortunei var. cyclolepis is an ideal tree species for mountain afforestation, timber forests, and landscaping. Its pollination process can be affected by the rainy season, making it difficult to pollinate the massive female cones, which leads to a high abortion rate and low quality of seeds. Here, we observed the pollen morphology of K. f. cyclolepis using scanning electron and light microscopes, investigated the characteristics of its in vitro germination by the detached method, and explored the effect of different storage temperatures and times on the pollen germination rate and the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Our results indicated that the pollen of K. f. cyclolepis is a five-cell pollen, comprising one noumenon and two air sacs, both of which were oval in polar view. The optimal condition for pollen germination of K. f. cyclolepis was 240 g/L sucrose + 70 mg/L CaCl2 + 210 mg/L H3BO3 at 24 °C and pH 6.0, resulting in a germination rate of 45.0%. The effects of different storage temperature and time on pollen germination rate varied significantly. The best storage temperature was − 80 °C, at which the germination rate was 20.9% after 365 days of storage, and the activity of three protective enzymes remained relatively high, representing relatively strong antioxidation and antiaging activity. Stepwise regression analysis showed that SOD was the main factor affecting the pollen germination rate of K. f. cyclolepis. The function of the three protective enzymes differed under various temperatures, for example, SOD served as a sensitive protective enzyme at room temperature, − 20 °C and − 80 °C, whereas both SOD and CAT served as sensitive protective enzymes at 4 °C.

The incorporation of Bacillus thuringiensis (Bt) rice straw into fields may influence the growth of subsequent crops, but its ecological risks for winter vegetables remain largely unreported. Investigating the effects of Bt rice straw extracts on the seed germination and plant growth of pakchoi (Brassica campestris L. ssp. Chinensis Makino var. communis Tsen et Lee) can provide a theoretical foundation for ecological risk assessments. In this study, straw extracts from non-Bt rice (Tianyouhuazhan), homozygous Bt rice (T775), and heterozygous Bt rice (F1 of T775 hybrid) were used as experimental materials at concentrations of 10, 20, and 40 g·L−1. Results showed that, compared to non-Bt extract, 40 g·L−1 homozygous Bt extract increased seedling height and leaf peroxidase (POD) activity but inhibited catalase (CAT) and root superoxide dismutase (SOD) activities. The 20 g·L−1 extract boosted root CAT activity yet suppressed leaf CAT and POD activities. The 10 g·L−1 extract enhanced root length but reduced leaf CAT and POD activities. The 40 g·L−1 heterozygous Bt extract increased leaf and root POD activity but inhibited germination rate and leaf SOD activity. The 10 g·L−1 extract promoted root length and seedling POD activity but suppressed leaf POD activity. In plant growth assessments, the 10 g·L−1 homozygous Bt extract reduced underground dry weight, and the 10 g·L−1 heterozygous Bt extract inhibited both above and underground dry weight, while the 20 g·L−1 heterozygous Bt extract increased aboveground dry weight. In conclusion, the effects of homozygous and heterozygous Bt rice straw extracts on pakchoi varied with concentration and physiological indices, showing no clear pattern. Optimizing straw return concentrations based on Bt rice variety differences is essential to mitigate ecological risks.

In order to study the adaptation ability of sweet sorghum (Sorghum bicolor L. Moench) in the Yellow River Delta, the sweet sorghum variety Mart was used in this study to determine the roles of different saline-alkaline ratio stress treatment during seed germination to seedling stage. The results showed that Na⁺ concentration had a significant impact on the seed germination, seedling growth, and plant survival of sweet sorghum. Increasing Na⁺ concentration led to a decline in germination rate, final germination percentage, survival percentage, plant height, and dry weight per plant, a prolonged mean time of germination, as well as loss of improvement effect of low-Na+ concentration. The interaction effect of Na⁺ concentration and pH on the mean time of germination and germination rate was not significant (p < 0.05). However, under the condition of low-Na⁺ concentration (100 mM), high pH reduced the mean time of germination and increased the germination rate, without decline in final germination percentage and survival percentage. Therefore, at least in the duration of seed germination to the harvest period in the research, the sweet sorghum was resistant to the pH stress (≥9.04) when the Na⁺ concentration was below 100 mM. When suffered from the saline-alkaline stress, the seedling of sweet sorghum was characterized by ecological adaptive features, such as decreased stem ratio and chlorophyll b content in leaves and increased root ratio and chlorophyll a content, in order to maintain the uptakes of water and nutrient, and carbon assimilation. When the stress intensified, the lipid oxidation products, e.g., malondialdehyde (MDA), increased in sweet sorghum seedlings. However, the increasing of soluble protein content and antioxidant enzyme activity (superoxide dismutase (SOD), guaiacol peroxidase (POD), and gatalase (CAT)) was only founded in neutral low-Na⁺ concentration treatment (A₁), which indicated that high-salt concentration and pH all elicited harmful effects and limited the self-healing ability of sweet sorghum seedlings. In all, in order to grow sweet sorghum in the saline-alkaline soils of the Yellow River Delta, the salt concentration and pH value of the soil must be taken into consideration, and seeding density should be increased and supported by appropriate irrigation measures to reduce saline-alkaline stress so as to ensure the survival and growth of sweet sorghum seedlings.