Effects of post-heading high temperature on some quality traits of malt barley

Global change is bringing barley with more frequency of suffering from high temperature. However, little has been known about the influence of high temperature on malt quality traits. In this study, we investigated the impact of 1-wk heat stress (32°C/26°C, day/night, 12 h/12 h) initiating from the 7th (HT7) and 14th (HT14) days after heading on some grain and malt quality traits of two barley cultivars. In comparison with normal temperature (24°C/18°C, day/night, 12 h/12 h), heat stress significantly reduced kernel weight, seed setting rate and grains per spike: HT7 having a larger effect than HT14. Meanwhile, total protein and β-glucan contents, and β-amylase and limit dextrinase activities were significantly increased under high temperature, with HT7-treated plants showing larger changes. Moreover, the different changes of four protein fractions under heat stress were found in the two barley cultivars, indicating the possibility of breaking positive association between protein content and enzyme activity.     

Physiological activities and expression of insecticidal protein in Bacillus thuringiensis transgenic cotton leaves subjected to high and low temperatures

This research was to investigate physiological activities and the expression of insecticidal protein in cotton leaves of Kemian 1, a widely grown cotton cultivar in the lower reaches of the Yangtze River, treated under high (40°C and 35°C) and low (25°C and 20°C) temperatures for 48 h. The main results indicated that the contents of free amino acid and malondialdehyde (MDA) increased during the heat and cold stress with the biggest increments in the first 12 h; and the content of soluble protein, activities of superoxide dismutase (SOD), and glutamic-pyruvic transaminase (GPT) decreased during the stress with the biggest decrements also in the first 12 h; the activity of nitrate reductase (NR) decreased in the first 24 h, and during the remaining 24 h its activity followed a gradual uptrend. The content of insecticidal protein in cotton leaves followed a downtrend during the stress, and the biggest decrements occurred in the first 12 h, suggesting that the expression of insecticidal protein was immediately inhibited during the process of stress. The results also indicated that physiological activities and the expression of insecticidal protein in cotton leaves were closely related. Compared with other stress temperatures, 40°C produced more immediate effects on the physiological activities and insecticidal protein content. In contrast to the peak flowering period, the physiological activities and insecticidal protein expression at the peak boll-setting period were more susceptible to heat and cold stress.     

Dynamics of Bt cotton Cry1Ac protein content under an alternating high temperature regime and effects on nitrogen metabolism

This study was conducted to investigate the effects of alternating high temperature on Cry1Ac protein content on Bt cotton cultivars Sikang 1(SK-1,a conventional cultivar)and Sikang 3(SK-3,a hybrid cultivar).In 2011 and 2012,cotton plants were subjected to high temperature treatments ranging from 32 to 40℃ in climate chambers to investigate the effects of high temperature on boll shell insecticidal protein expression.The experiments showed that significant decline of the boll shell insecticidal protein was detected at temperatures higher than 38℃ after 24 h.Based on the results,the cotton plants were treated with the threshold temperature of 38℃ from 6:00 a.m.to 6:00 p.m.followed by a normal temperature of 27℃ during the remaining night hours(DH/NN)in 2012 and 2013.These treatments were conducted at peak boll growth stage for both cultivars in study periods of 0,4,7,and 10 d.Temperature treatment of 32℃ from 6:00 a.m.to 6:00 p.m.and 27℃ in the remaining hours was set as control.The results showed that,compared with the control,after the DH/NN stress treatment applied for 7 d,the boll shell Cry1Ac protein content level was significantly decreased by 19.1 and 17.5% for SK-1 and by 15.3 and 13.7% for SK-3 in 2012 and 2013,respectively.Further analysis of nitrogen metabolic physiology under DH/NN showed that the soluble protein content and the glutamic pyruvic transaminase(GPT)activities decreased slightly after 4 d,and then decreased sharply after 7 d.The free amino acid content and the protease content increased sharply after 7 d.The changes in SK-1 were greater than those in SK-3.These results suggest that under DH/NN stress,boll shell Cry1Ac protein content decline was delayed.Reduced protein synthesis and increased protein degradation in the boll shell decreased protein content,including Bt protein,which may reduce resistance to the cotton bollworm.     

Effects of Root-Zone Temperature on Growth,Chlorophyll Fluorescence Characteristics and Chlorophyll Content of Greenhouse Pepper Plants Grown under Cold Stress in Southern China

In Southern China, plants are usually exposed to cold stress during winter in an unheated greenhouse, but due to the high energy consumption and costs, most of the greenhouses remain unheated. In an attempt to find a simple and affordable solution to this problem, this study was undertaken. In this research, Capsicum frutescens L. plants were studied to investigate the effect of different root zone temperatures on its growth and chlorophyll fluorescence characteristics under cold stress. The plants were cultivated under cold stress conditions in a root zone temperature (RZT) control system where the roots were subjected to four different root-zone temperature treatments of 20°C-T20, 25°C-T25, 45°C-T45 and a control CK group. Growth characteristics studied included plant height, stem diameter, plant width, root length, biomass accumulation. Whilst fluorescence characteristics investigated were chlorophyll fluorescence ratio F_v/F_m, photochemical quenching (qL), efficiency of Photosystem II (Y[II]) and electron transport rate (ETR). Chlorophyll content in the leaves of the plants was also investigated. The findings demonstrated that plants in the CK group suffered a detrimental effect on the growth characteristics registering the lowest values in the measured variables. Conversely, the highest values were observed in T25 RZT treatment. In fluorescence characteristics, values of F_v/F_m were maintained at between 0.8 and 0.83 but also suffered a photo-inhibitory depression in CK and T45 RZT treatments to F_v/F_m values of <0.79. This depicted that root zone heating protected the PS II of these plants from photoinactivation induced by cold stress. Similar trends were seen in the qL, Y[II], ETR values with the T20 and T25 treatments registering the highest values. Chlorophyll content was significantly higher in the leaves of the plants in the T20 and T25 group. The lowest chlorophyll content was recorded in the CK group. Plants in all the treatments accumulated more biomass in the shoot than in the roots as depicted by a significantly lower shoot to root ratio values with the exception of those in the CK group. The findings of this study suggest that pepper plants can successfully be grown in an unheated greenhouse in the Yangtze River Delta area of Southern China during winter by heating the root zone of the plants to a RZT value of 25°C, thereby providing a simple, affordable and cost-effective technique.     

Effects of constant and stage-specific-alternating temperature on the survival,development and reproduction of the oriental armyworm,Mythimna separata (Walker) (Lepidoptera: Noctuidae)

Migratory insects make diverse adaptive strategies in response to changes in external environment. Temperature has an impact on the survival, development, reproduction, and migration initiation of insects. Previous research has primarily been focused on the effects of constant temperature on populations, but changing temperature has received less attention. Three constant temperature treatments(20, 25 and 30°C) and three pupal-alternating temperature treatments(20–25, 25–20 and 25–30°C) were set up to study the relationship between temperature and population development by age-stage, two-sex life table analysis in the oriental armyworm, Mythimna separata Walker, a notorious migratory pest in grain crops. The 25°C treatment was considered optimal with 20 and 30°C as low suitable temperature and high temperatures, respectively. The survival rate was relatively low before third instar larvae at 20°C(63.0%) and 20–25°C(70.1%), and extreme low after pupal stage at 30°C(20.6%). Developmental duration of each stage was negatively correlated with temperature. The adult preoviposition period, when most migratory insects initiate migration, was the shortest at 25°C(2.69d) but was lengthened at both low suitable(7.48d for 20°C, 6.91d for 25–20°C and 4.57d for 20–25°C) and high temperatures(3.74d for 25–30°C and 5.00d for 30°C). Both low suitable and high temperature decreased lifetime fecundity, net reproductive rate and the intrinsic rate of increase, with variability observed across developmental duration and stage during non-optimal temperature. The results expand knowledge of the relationship between changing temperature and armyworm population development, and adaptive strategies in complex ambient environment.     

电导法结合Logistic方程对6个文冠果种质抗寒性的评价

为了评价引进文冠果种质的抗寒性,为其进一步栽培和育种利用提供参考,以引进种质6份文冠果种质((G27、BD12、BD特异、建2、株系2、G13))为试材,设置-10 °C、-20 °C、-30 °C低温胁迫梯度,测定相对电导率,并拟合Logistic方程计算半致死温度(LT50),评价供试种质抗寒性强弱。结果显示供试种质半致死温度分别是-13.272、-12.244、-11.543、-8.246、-5.643、-2.642 ℃,依据半致死温度评价抗寒性强弱为BD特异>G27>BD12>建2>G13>株系2。相对电导率结合Logistic方程评价文冠果种质抗寒性结果与前期研究结果基本一致,可作为评价种质抗寒性的简要方法之一,同时为引进种质进一步在新疆地区栽培与育种利用提供参考。     

Application of brassinolide alleviates cold stress at the booting stage of rice

The objective of the study was to determine the physiological mechanisms of plants in response to brassinolide(BR) alleviating cold water stress on rice. In this study, physiological responses of rice to exogenous BR and cold water submergence were investigated using the chilling-tolerant cultivar Kongyu 131(KY131) and the chilling-sensitive cultivar Kenjiandao 6(KJD6). A total of 2 mg L~(–1) BR increased activities of superoxide dismutase(SOD) and peroxidase(POD) and the contents of soluble sugar, soluble protein, and chlorophyll, but decreased the malondialdehyde(MDA) content in KY131 and KJD6 under cold water stress. The observed decreases in SOD and POD activities and MDA content recovered quickly after plants were returned to irrigation with water at temperatures of about 23.0°C in 2014. Additionally, the contents of nitrogen(N), phosphorous(P), and potassium(K) were increased by BR treatment under cold water stress. Exposure to BR also raised the percentage of high effective leaf area and leaf area index at the heading stage. Furthermore, it promoted soluble sugar synthesis, increased the rate of dry matter accumulation, and enhanced the export and translocation rates of the stem-sheath. The yield in KJD6 was significantly(P≤0.01 and P≤0.05) higher than that of the control in 2013 and 2014, respectively. The effect of BR treatment on rice leaf SOD and POD activities, MDA, chlorophyll, P, and stem-sheath K contents were more significant in KJD6 than in KY131. In conclusion, exogenous BR effectively reduced the physiological and metabolic damage in rice due to cold stress at the booting stage, promoted functional recovery in plants that received irrigation with water at a normal temperature following cold stress, and mitigated the effects of cold water stress on yield.The two varieties exhibited differential responses to BR; the weaker cold-resistant variety was more sensitive to BR and displayed stronger responses to exogenous BR.     

Studies on isolated microspore embryoid induction of <Emphasis Type="Italic">C. annuum</Emphasis> L.

A system to improve isolated microspore embryoid induction rate of pepper (Capsicum annuum L.) was studied in this paper. The results showed that low-temperature pretreatment, growth regulators combinations, activated carbon concentrations, and preculture temperatures were critical factors affecting embryoid formation of isolated pepper microspores in vitro. One day after pretreatment of the buds at 4°C, the anthers that differentiated and developed into embryos were cultured in double-layer medium system for one week at 7°C and then went on culturing at 28°C in darkness. All the seven genotypes of the tested pepper responded to this protocol. The embryoid induction rate of the best genotype increased from 81.11% to 147.22%. This protocol can be used as a potential tool for producing doubled haploid plants for pepper breeding.     

Characterization of T-complex polypeptide 1 (TCP-1) from the Chilo suppressalis HSP60 family and its expression in response to temperature stress

Many proteins require assistance from molecular chaperones at various stages to attain correctly folded states and functional conformations during protein synthesis. In this study, the gene encoding T-complex polypeptide 1(TCP-1), which belongs to the heat shock protein 60(HSP60) family, was isolated and characterized from the rice stem borer, Chilo suppressalis, by RACE and q PCR, respectively. The full-length c DNA of Tcp-1 was 2 144 bp and encoded a 1 635-bp ORF; the deduced translational product contained 545 amino acids with 5′-and 3′-UTRs and an isoelectric point of 5.29. Cluster analysis confirmed that the deduced amino acid sequence shared high identity(60–99%) with TCP-1 from other insects. To investigate Tcp-1 expression in response to abiotic stress, q PCR was used to analyze expression levels of Tcp-1 m RNA in C. suppressalis larvae exposed to temperatures ranging from –11 to 43°C. With respect to heat shock, Tcp-1 expression was higher than the control after a 2-h exposure to 30 and 36°C and declined at 39 and 43°C. Difference in Tcp-1 expression was observed at temperatures ranging from –11 to 27°C. q PCR analyses revealed that Tcp-1 expression was the highest in hindgut tissue as compared to heads, epidermis, fat body, foregut, midgut, and malpighian tubules. Our results indicated that Tcp-1 expression was differentially expressed in C. suppressalis tissues, and was impacted by temperature stress.     

The effect of elevating temperature on the growth and development of reproductive organs and yield of summer maize

Compared to other crops, maize production demands relatively high temperatures. However, temperatures exceeding 35℃ lead to adverse effects on maize yield. High temperatures(≥35℃) are consistently experienced by summer maize during its reproductive growth stage in the North China Plain, which is likely to cause irreversible crop damage. This study investigated the effects of elevating temperature(ET) treatment on the yield component of summer maize, beginning at the 9th unfolding leaf stage and ending at the tasseling stage. Results demonstrated that continuous ET led to a decrease in the elongation rate and activity of silks and an elongated interval between anthesis and silking stages, and eventually decreased grain number at ear tip and reduced yield. Although continuous ET before tasseling damaged the anther structure, reduced pollen activity, delayed the start of the pollen shedding stage, and shortened the pollen shedding time, it was inferred, based on phenotypical and physiological traits, that continuous ET after the 9th unfolding leaf stage influenced ears and therefore may have more significant impacts. Overall, when maize plants were exposed to ET treatment in the ear reproductive development stage, the growth of ears and tassels was blocked, which increased the occurrence of barren ear tips and led to large yield losses.     

High temperatures do not decrease biocontrol potential for the host-killing parasitoid Neochrysocharis formosa (Hymenoptera: Eulophidae) on agromyzid leafminers

Temperature, as a critical abiotic factor, might influence the effectiveness of biological control by parasitoids in host-parasitoid systems. In this study, Neochrysocharis formosa (Westwood), a larval endoparasitoid, is used to investigate the efficacy of biological control on a vegetable agriculture pest, Liriomyza sativae Blanchard, reared on kidney bean (Phaseolus vulgaris L.), at four constant temperatures (26, 29, 32, and 35°C) under laboratory conditions. Our results show that high temperatures (29, 32, and 35°C) do not significantly affect lifetime host-killing events of female adults by increased daily host-killing events compared to temperature of 26°C, although their lifespans decrease with an increase in temperatures. Each life-history trait of female adults (lifespan, parasitism, stinging, or non-reproductive host-killing events) present a linear relation with temperatures and host-feeding events, respectively. Our findings contribute to a better understanding of biocontrol efficacy of parasitoid N. formosa against agromyzid leafminers at high-temperature seasons or environments.     

Isolated pea anther culture

Callus tissues and green globular embryoids are obtained in a pea anther culture on a medium with 2,4-D after cold (4°C) treatment of buds. In experiments with the use of treating buds with cold (4°C) and anther culture with heat (32 and 35°C), green embryogenic and morphogenetic calli are induced and regenerant plants are obtained. The origin of the regenerants is established by genetic markers.     

Effects of Environmental Temperature on the Regeneration Frequency of the Immature Embryos of Wheat （Trificum aestivum L.）

The immature embryos （IEs） of wheat are the most widely used tissues for in vitro culture and genetic transformation due to its high regeneration competency. However, this explant can only be maintained in 4℃ daily cooler for a short period time for its use in plant tissue culture or transformation experiments. This study aimed to investigate the effects of environmental temperature, cryopreservation storage temperature, and heat shock culture （HSC） temperature on the regeneration frequency of wheat IEs. Results indicated that environmental temperature significantly affected the induction of embryonic calli. The optimum total accumulated temperature （TAT） during the time of anthesis and sampling for regeneration of these tissues was around 280℃ for spring wheat type cv. CB037 and approximately 300℃ for winter wheat type cv. Kenong 199. Regeneration ability obviously declined when the highest environmental temperature was over 35℃ for 1 d or a high temperature between 30 and 33℃ lasted for 5 d during anthesis and sampling. This finding was verified by culturing the freshly isolated IEs under different temperatures from 29 to 37℃ in different controlled growth incubators for 5 d; the IEs almost completely lost regeneration ability when the temperature rose to 37℃. Cryopreservation of-20℃ caused the wheat samples lost ability of producing callus or embryonic callus in a few days, and cryopreservation of-10℃ more than 10 d made the regeneration potential of the tissues dramatically declined. Comparatively, the temperature that best maintained high regeneration ability was -5℃, at which the materials can be maintained for around 1 mon. In addition, the preservation of the immature samples at -5 or -10℃ inhibited the direct germination of the IEs, avoiding the embryo axis removing process. Our results are useful for ensuring that field collection and cryopreservation of the wheat IEs are done correctly to enable tissue culture and genetic transformation.     

Effect of weak magnetic field and low positive temperature on chromatin and nucleolus ultrastructure of rye and barley

Using two crops (rye, barley) we have demonstrated a fundamental difference in the structural organization of condensed chromatin, nucleolus and chromatin-RNP complexes in the experiments with the weakening (spherical ferromagnetic shield) and the enhancing (constant magnet) of magnetic field at low positive (−3-+1°C) and room temperatures (+24°C). As a model we used the spring and winter varieties of cereals placed after imbibition in the experimental conditions. We used the classic regime of seed vernalization (12 and 42 days at temperatures ranging from 0 to +4°C) for winter cereals and temperate climate zones of germination at room temperature in the control and experimental conditions.     

Effects of Dietary Protein and Temperature on Growth and Flesh Quality of Songpu Mirror Carp

The study was conducted to demonstrate the effects of dietary protein and water temperature on growth and flesh quality of Songpu mirror carp （Cyprinus carpio） at an initial weight （165.24±5.08） g. Practical diets were formulated to contain five protein levels （29.12%, 31.46%, 34.49%, 38.17%, and 40.13%）, and each diet was randomly assigned triplicate groups of 15 fishes at three temperatures （18℃, 22℃, and 26℃） in the recirculation system. Fishes were fed twice daily to apparent satiation for 56 days. Results indicated that fishes had higher weight gain rate at 22℃ and 26℃ than that at 18℃ （P〈0.05）, but there were no significant differences between 22℃ and 26℃ （P〉0.05）. Based on the weight gain rate, dietary protein level 29.12% could meet the requirement of the body at 18℃, 22℃, or 26℃. Crude protein, crude lipid, moisture and ash of muscle had no significant differences among those treatments （P〉0.05）. pH （after 24 h） of muscle was the highest at 18℃ and the lowest at 22℃ （P〈0.05）, but no differences were observed among different protein level groups at each temperature （P〉0.05）. No significant differences on shear force, water holding capacity, collagen, glycogen and lactate among all the treatments were found （P〉0.05）. It was concluded that when C. carpio fed to apparent satiation, the growth mainly depended upon temperature. Dietary protein could not significantly affect flesh quality, but temperature significantly affected pH of muscles. A dietary protein level 29.12% could meet the requirement of the body at 18℃, 22℃, or 26℃.     

Effect of dry and wet storage at cool temperatures on the post-harvest performance of Ranunculus asiaticus L. flowers

A study was undertaken to assess the effect of different storage temperatures on senescence and postharvest performance of isolated flowers of Ranunculus asiaticus L.. The main aim of the work was to develop a cost-effective storage protocol to reduce the postharvest losses and to bring out the transportation of cut flowers of R. Asiaticus. The flowers were subjected to two different storage treatments, dry storage and wet storage, and their postharvest performance was compared under laboratory conditions. For this purpose, the buds were harvested at 8:00 AM at loose bud stage (Stage II of flower development). The harvested buds were cut to a uniform size of 15 cm and processed for dry or wet storage. For dry storage, the buds were packed after wrapping them in moistened filter papers and kept at 5°C and 10°C. For wet storage, the buds were held in distilled water in separate glass beakers kept at 5°C and 10°C, respectively. A separate set of buds each for dry and wet storage was kept at room temperature (15±2)°C. After 72 h storage, the buds were kept at room temperature in distilled water. The average life of an individual flower that opened fully was about 4–5 days. The buds kept under wet storage at 5°C and 10°C for 72 h maintained their premature status, while the buds held at room temperature for 72 h generally bloomed. All the buds stored dry maintained their premature status irrespective of storage temperature. Storage of buds for 72 h at 5°C, followed by transferring to distilled water improved the longevity by about 5 to 6 days. Cold storage treatment before transferring to holding solution improved floral diameter, membrane integrity besides maintaining higher fresh and dry mass of flowers, sugar content, soluble proteins, and phenols. Our results suggested that wet and dry storage of premature buds of R. asiaticus for 72 h at 5°C, followed by placing them in distilled water, improved the cut flower longevity and can be used as effective postharvest storage treatments for this beautiful cut flower.     

Effect of Water Temperature on Feeding Rhythm in Common Carp （ Cyprinus carpio haematopterus Temminck et Schlegel）

Feeding rhythm of common carp was investigated from 4°cC to 34°C. The results indicated that there was a diel feeding rhythm for both adult (630–850 g) and youth (61–91 g) at all tested temperatures. There were two main activity peaks at 8:00–11:00 a.m. and 19:00–23:00 p.m., during which feeding quantities were 10.68%–32.53% and 16.25%–33.41% of the daily intake, respectively. When water temperature dropped to below 10°C, the feeding peak concentrated at 8:00–11:00 a.m. and 19:00 p.m. to 4:00 a.m. At 6°C, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14°C, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28°C, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34°C, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures (P<0.05).     

Development of an early warning system for brown planthopper (BPH) (<Emphasis Type="Italic">Nilaparvata lugens</Emphasis>) in rice farming using multispectral remote sensing

The spread of rice pests such as BPH in tropical areas is one of the best-known yield lost factors. Remote sensing can support precision farming practices for determining the location of spreads and using pesticide in the right place. In a specifically conducive environment like high temperature and heavy rainfall, BPH population will increase. To address this issue, detection of sheath blight in rice farming was examined by using SPOT-5 images. Also, the extraction of weather data derived from Landsat images for comparing with the BPH infestation was undertaken. Results showed that all the indices that recognize infected plants are significant at α = 0.01. Examination of the association between the disease indices indicated that band 3 (near infrared) and band 4 (mid infrared) in SPOT-5 images have a relatively high correlation for detecting diseased part from healthy ones. The selected indices declared better association for detecting healthy plants from diseased ones. Image investigations revealed that BPH were existing at the higher limits of tolerable temperatures when in the form of nymphs. With the knowledge that the late growth stage of plants has more severe BPH attacks, the results stated that BPH outbreak is particularly obvious in the north-west corner and middle regions of the maps and it is more likely to happen in specified ranges of temperature and RH, i.e. 29 °C <T< 32 °C, and 88 % <RH< 93 %.