Effect of Low Temperature and Sparse Light Conditions on Cold Tolerance of Different Rice Lines at Seedling Stage

Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of 36 parents and 423 rice lines from 68 hybrid groups were investigated at seedling stage under low tempera- ture and sparse light conditions in field. There were 10 parent accessions with strong cold tolerance of level 1. Among them, 3 were common wild rice accessions; 4 were japonica rice cultivars; 2 were indica rice; 1 was offspring from hybrid be- tween indica and japonica.There were 33 lines with strong cold tolerance of level 1 from the hybrid groups of common wild rice,and 15 from the hybrid groups of IRBB5, and only 3 from the hybrid groups of BPHR96. There were abundant cold tolerance resources in rice germplasm. It was feasible to develop cold tolerance cul- tivars from the hybrids among common wild rice, japonica cultivars and indica culti- vars.

The Physiologic Reaction of Cucumber to Low Temperature and Low Light Intensity

The dynamics of chlorophyll content, leaf area and photosynthesis of cucumber seedlings were studied under sole stress of two low temperatures and low light intensity as well as combined stresses of low light intensity and the two low temperatures. The results showed that low light intensity reduced sensitivity of cucumber to low temperature and improved chlorophyll content, leaf area and chlorophyll fluorescence quantum yield. The photosynthesis rate was reduced under low light intensity. The intensity of light played the leading role in growth of cucumber under the low temperature condition, while the low temperature played the leading role under the critical low temperature condition. There were differences in reaction to light and temperature among different varieties. The tolerance to low temperature and low light intensity was not always synergetic for the same cucumber variety.

Effects of Acetylsalicylic Acid and Calcium Chloride on Photosynthetic Apparatus and Reactive Oxygen-Scavenging Enzymes in Chrysanthemum Under Low Temperature Stress with Low Light

The effects of acetylsalicylic acid （ASA）, CaCl2, and ASA ＋ CaCl2 on the photosynthetic apparatus and antioxidant enzyme activities were investigated in chrysanthemum Jinba （a cut flower cultivar） under low temperature stress with low light （TL stress） （16/12℃, day/night, PFD 100 μmol m^-2 s-1）. The results showed that under TL stress, the net photosynthesis rate （Pn）, carboxylation efficiency （CE）, apparent quantum yield （AQY）, maximal photochemical efficiency （Fv/Fm） of PSII, quantum yield of PSII electron transport （ФPSII）, and photochemical quenching （qP） of the chrysanthemum leaves in all treatments were significantly decreased, but the decreases were alleviated by ASA, CaCl2, and ASA ＋ CaCl2 treatments compared with the controls. The alleviating effect of ASA ＋ CaCI2 was better than either ASA or CaCl2 single treatment. Moreover, the ASA ＋ CaCl2 treatment highly improved the chlorophyll content, relatively improved the number and size of chloroplast and starch grain in the leaves of chrysanthemum plants compared with ASA and CaCl2 treatments. It was indicated that ASA and/or CaCI2 could regulate the photosynthetic functions in the leaves of chrysanthemum plants to enhance the resistance against TL stress. On the other hand, reduction in relative conductance rate implied that ASA and/ or CaCl2 could protect from membrane injury in leaves of chrysanthemum plants. The activities of SOD, POD, and CAT in the treated leaves of chrysanthemum were increased as compared with the controls. It was suggested that ASA and/or CaCl2 had positive regulation effects on the defence enzyme activities in chrysanthemum leaves which could protect the photosynthetic apparatus to a certain degree under the TL stress. In brief, the treatment of ASA together with CaCl2 was better for chrysanthemum plants to adapt TL stress than single ASA or CaCl2 treatments.

Effects of Phosphate Fertilizer on Cold Tolerance and Its Related Physiological Parameters in Rice Under Low Temperature Stress

The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings （chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81） under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.

Evaluation of Rice Seedling Tolerance to Constant and Intermittent Low Temperature Stress

M202, IR50 and advanced backcross （BC4F6） lines carrying the cold tolerance QTLs qCTS4 and qCTS12 were evaluated using three low temperature stress assays （constant, intermittent and constant with recovery period）. Under constant stress, two BC4F6 lines （MIb 4853-9 and MIb 6885-2） exhibited differences in seedling growth and accumulation of stress-related compounds although both carry the two QTLs in the IRS0 background. Differences between these lines were also observed in the constant with recovery period assay, although both of them performed comparably under intermittent stress, MIb 6885-2 performed more similarly to M202 in the constant and constant with recovery period assays, suggesting that this line contains an introgressed region（s） not present in MIb 4853-9. The three assays were also applied to assess variations in cold tolerance in a set of diverse germplasms. Performance metrics and visual ratings were comparable for evaluating tolerance to constant stress. However, differences in response to intermittent stress were more evident from growth and total chlorophyll measurements than from visual ratings. With regard to the constant with recovery period assay, about 15% of the germplasm accessions did not recover. However, some lines which exhibited chilling injuries of comparable severity were able to overcome them. This recovery phenotype may improve rice performance in the field and warrant further investigation.

Low Temperature Tolerance of Parental,Inbred and Hybrid Lines of Brassica Napus at Germination Stage

In order to screen rapeseed accessions with low temperature tolerance in triple cropping area,comprehensive membership function method was used to evaluate the low temperature tolerance of 176 accessions including inbred and hybrid lines of Brassica napus with germination rate,germination energy,germination index and average germination time as indicators.The results showed that 103 accessions with strong low temperature tolerance and 27 accessions with sensitive to low temperature stress were identified.The low temperature tolerance was significant different among accessions(P<0.001)while insignificantly different among different types(sterile lines,maintainer lines,restorer lines,and hybrid lines,P=0.07).The integrated membership function value was significantly correlated with germination rate,germination index and average germination time,which provided valuable information for the future breeding of low temperature tolerant varieties,especially in the middle reaches of the Yangtze River basin.

Effects of Low Temperature-tolerant Microbial Inoculants from Municipal Solid Waste Compost on Turf Storage in Winter

Beneficial microorganisms were extracted from municipal solid waste compost and treated under low temperature stress to prepare complex microbial inoc- ulants. Turfgrass was inoculated with the prepared microbial inoculants to investigate the ecological effect of ~crobial inoculants on turf storage in winter. The re- suits showed that complex low temperature tolerant microbial inoculants significandy improved plant height and aboveground biomass of turfgrass. Compared with the non-inoculated control, plant height and biomass of the first batch of inoculated turfgrass were enhanced by 6.47% and 14.32%, respectively; and they were en- hanced by 6.94% and 17.41%, respectively, for the second batch of inoculated turfgrass. Under low temperature stress in winter, the reviving rate of inoculated tarfgrass was significandy higher than that of control, which was improved by 3.34% and 43.33% for the first and second batches of inoculated turfgrass respective- ly. After low temperature storage in winter, inoculated turfgrass revived in advance; specifically, the reviving date of the second batch of inoculated turfgrass was 3 d earlier than that of control. This low temperature tolerant microbial consortium was effective for turfgrass as an ecofriendly and acceptable technology to improve plant performance and development in winter and accelerate time to market of turf.

Ambient Light Alters Gene Expression Pattern of Enzymes and Transcription Factors Involved in Phenylpropanoid Metabolic Pathway in Potato under Chilling Stress

[Objective] Expressions of key enzymatic genes involved in phenyl-propanoid metabolic pathway in potato and StR2R3-MYB and StTGA transcripters were investigated in the present study. [Method] The primitive cultivar Yan was the materials for replicated trials and total RNA extracted from tissues of seedlings. Re-al-time florescent quantification PCR, multiple intervals of air temperature, light-il umi-nation and time-duration were factors of treatments in the experiment. Data on gene expressions were obtained and proceed to asses and compare effects based on statistical analysis. [Result] The results showed negative correlations between tem-perature degrees and expressions of StPAL, StDFR and StR2R3-MYB genes but not StTGA. Positive correlations, however, were derived between those of StCHS, StDFR and StR2R3-MYB and light-intensity. Significant interactive effects between expressions of StPAL and StDFR and treatments, light intensity and temperature degree, along the phenylpropanoid pathway were observed. Transcription regulator of StR2R3-MYB showed significant positive effect on the expression of StCHS of potato. StTGA transcription factor, on the other hand, gave significant negative ef-fects on the expression of StDFR. [Conclusion] Results from present study reveal the role of environmental factors and complicate interactions between such condi-tions as temperature-light il umination and mRNA function of target genes.

Identification and Evaluation of Cold Tolerance in Bitter Gourd (Momordica charantia L.) at Bud and Seedling Stages under Different Temperature Conditions

[ Objectives] This study was conducted to screen the temperature index most suitable for identification of cold tolerance in bitter gourd （Momordica charantia L. ） at bud and seedling stages. [ Methods] With six different bitter gourd germplasms as experimental materials, the cold tolerance at bud and seedling stages were identified and evaluated. [ Results] At 18℃ , the largest change range of germination potential among different gernlplasms was 11.3% -96.0%, and the largest change range of germination rate was 13.3% - 100.0% ; and the six germplasms could be divided into three grades of cold tolerance. Therefore, 18 9C is an ideal temperature for the identification of cold tolerance in bitter gourd germplasms at bud stage. At 20℃, the cold tolerance in bitter gourd germplasms at bud stage could also be divided into three grades, and the change ranges of germination potential and germination rate were larger than 50.0%, so 20℃ could serve as the candidate temperature for the identification of cold tolerance in bitter gourd germplasms at bud stage. After 1 d of treatment at 6℃, the six bitter gourd germplasms could be divided into three grades, and the cold injury index had the largest range of 20.31 - 84.38 and could serve as the temperature index for the identification of cold tolerance in bitter gourd at seedling stage. [ Conclusions] This study will provide reference for the identification of cold tolerance in bitter gourd at bud stage and seedling stage.

Low temperature-mediated repression and far-red light-mediated induction determine morning FLOWERING LOCUS T expression levels

In order to flower in the appropriate season,plants monitor light and temperature changes and alter downstream pathways that regulate florigen genes such as Arabidopsis(Arabidopsis thaliana)FLOWERING LOCUS T(FT).In Arabidopsis,FT messenger RNA levels peak in the morning and evening under natural long-day conditions(LDs).However,the regulatory mechanisms governing morning FT induction remain poorly understood.The morning FT peak is absent in typical laboratory LDs characterized by high red:far-red light(R:FR)ratios and constant temperatures.Here,we demonstrate that ZEITLUPE(ZTL)interacts with the FT repressors TARGET OF EATs(TOEs),thereby repressing morning FT expression in natural environments.Under LDs with simulated sunlight(R:FR=1.0)and daily temperature cycles,which are natural LD-mimicking environmental conditions,FT transcript levels in the ztl mutant were high specifically in the morning,a pattern that was mirrored in the toe1 toe2 double mutant.Low night-to-morning temperatures increased the inhibitory effect of ZTL on morning FT expression by increasing ZTL protein levels early in the morning.Far-red light counteracted ZTL activity by decreasing its abundance(possibly via phytochrome A(phyA))while increasing GIGANTEA(GI)levels and negatively affecting the formation of the ZTL-GI complex in the morning.Therefore,the phyA-mediated high-irradiance response and GI play pivotal roles in morning FT induction.Our findings suggest that the delicate balance between low temperature-mediated ZTL activity and the far-red light-mediated functions of phyA and GI offers plants flexibility in fine-tuning their flowering time by controlling FT expression in the morning.

A low temperature processable tin oxide interlayer via aminemodification for efficient and stable organic solar cells

The exploitation of proper electron transport layers(ETLs)and interface optimization can play a pivotal role to promote the performance of organic solar cells(OSCs).In this work,low temperature processable tin oxide(SnO_(2))colloidal nanoparticles with ethanolamine(EA)treatment are successfully employed for efficient and stable OSCs with light soaking free.The EA is chemically bonded with SnO_(2),and the ethanolamine treated tin oxide(E-SnO_(2))layer delivers a suitable work function of 4.10 eV and a unique surface texture with suspended polar moieties.The enhanced performance of E-SnO_(2) based OSCs can be attributed to the improved charge transport and electron extraction,which is correlated with the regulated energy level alignment and contact quality of E-SnO_(2)/active layer.As a result,considerable power conversion efficiencies(PCEs)of 10.30%,13.93%and 15.38%for PTB7-Th/PC_(71) BM,PM7/ITC6-4 F and PM6/Y6 based OSCs have been realized with E-SnO_(2) as ETL,respectively.Compared with ZnO based devices,the E-SnO_(2) based OSCs exhibit an improved light aging stability,which can retain 94.3%of their initial PCE of 15.38%after 100 h light aging for E-SnO_(2)/PM6/Y6 based OSCs.This work demonstrates that the enormous potential of E-SnO_(2) to serve as ETL for high-efficiency and stable OSCs.

Annealing Temperature-Dependent Luminescence Color Coordination in Eu-Doped AlN Thin Films

AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.

Role and Mechanism of Action of Exogenous Salicylic Acid and Sodium Molybdate in Improving Cold Tolerance of Bougainvillea glabra

This study was conducted to comprehensively evaluate the effects of salicylic acid and sodium molybdate on cold tolerance of an ornamental plant Bougainvillea glabra and to provide a theoretical guidance for landscape maintenance.B.glabra plants were treated with 0.5 mmol/L salicylic acid and 2.0 μmol/L alone or in combination,and then exposed to low temperature stress before physiological indices were measured.The results showed that all salicylic acid and sodium molybdate treatments reduced the relative conductivity and malondialdehyde( MDA) content of B.glabra to varying extents under the stress of low temperature,and more significant effect was achieved by using the two agents in combination.Oxygen free radicals production rate increased with decreasing temperature from 20 to 6 ℃,but declined with temperature decreasing from 3 to-3 ℃.The SOD activity of the control( CK) was significantly lower than that of other treatments at 0 and-3 ℃.The treatments with salicylic acid and sodium molybdate alone and in combination increased POD activity of B.glabra plants,especially at 0 ℃,as the POD activity of treatments T1,T2 and T3 was significantly higher than that of CK at 0 ℃.In addition,under low temperature stress,the contents of soluble sugar,starch and proline increased initially and decreased subsequently with temperature decreasing.The soluble sugar content at 3 ℃,starch and proline contents at 0 and-3 ℃ in treatments with salicylic acid and sodium molybdate alone and in combination were significantly higher than those of CK.All above results proved that salicylic acid and sodium molybdate are able to improve cold tolerance of B.glabra,and better effect can be achieved by using them together.

Combining QTL mapping and expression profile analysis to identify candidate genes of cold tolerance from Dongxiang common wild rice(Oryza rufipogon Griff.)

Rice（Oryza sativa L.）, a tropical and subtropical crop, is susceptible to low temperature stress during seedling, booting, and flowering stages, which leads to lower grain quality levels and decreasing rice yields. Cold tolerance is affected by multiple genetic factors in rice, and the complex genetic mechanisms associated with chilling stress tolerance remain unclear. Here, we detected seven quantitative trait loci（QTLs） for cold tolerance at booting stage and identified one cold tolerant line, SIL157, in an introgression line population derived from a cross between the indica variety Guichao 2, as the recipient, and Dongxiang common wild rice, as the donor. When compared with Guichao 2, SIL157 showed a stronger cold tolerance during different growth stages. Through an integrated strategy that combined QTL-mapping with expression profile analysis, six candidate genes, which were up-regulated under chilling stress at the seedling and booting developmental stages, were studied. The results may help in understanding cold tolerance mechanisms and in using beneficial alleles from wild rice to improve the cold tolerance of rice cultivars through molecular marker-assisted selection.

Chilling Tolerance and Physiological Parameters as Influenced by Grafting in Watermelon Seedlings

The influences of different rootstocks on chilling tolerance and physiological parameters in watermelon seedlings have been studied. The results showed that grafting improved the chilling tolerance. Compared with own-rooted watermelon seedlings, the grafted watermelon seedlings had lower chilling injury index, lower electrolytic leakage (%), lower malondialdehyde (MDA) content, higher chlorophyll and proline content, and higher activities of superoxide dismutase (SOD), ascorbate peroxidase (AsA-POD) and dehydroascorbate reductase (DR) in the leaves under low temperature stress. There was a considerable difference of chilling tolerance among different grafted watermelon seedlings due to the difference of rootstock chilling tolerance. After low temperature treatment, the grafted seedling with higher chilling tolerance had lower electrolytic leakage (%),lower MDA content, higher proline content and higher activities of SOD, AsA-POD and DR in the leaves compared with the grafted seedling with weaker chilling tolerance. From these, we could conclude that chilling tolerance of watermelon seedlings may be related to higher antioxidative ability and membrane stability in the plants. The chilling tolerance of grafted seedling could be properly evaluated by comprehensive physiological indexes but not a single physiological index.

Low temperature doping of anatase nano TiO2

In this paper. Glucose, nitrate, and urea were respectively used as C, B, and N sources doped TiO2 at low temperature sol gel method, The obtained nano TiO2 was characterized by DRS, FIRT, TG-DTG. The photocatalytic properties and the optical response range of the natase nanocrystalline were analyzed and studied with the hybrid orbital theory. The results show that the band gap of the doped TiO2 was narrow, and the photocatalytic ability could be excited by the visible lighL and the doping of non metallic elements broadens the application range of TiO2, so that it could be excited under the visible light and obtained better use value.

优质甜玉米骨干系在低温下种子萌发及幼苗抗性研究

甜玉米普遍存在种子发芽率低及对低温敏感的问题。为探明甜玉米种子发芽和幼苗对低温耐受性,本研究选取12份甜玉米骨干自交系,分别于25、18和12℃温度下测定萌发相关生理指标,结合相关性及聚类分析,筛选出低温萌发优势材料;选取5份优势材料开展幼苗4℃低温处理,进行耐寒相关生理指标比较及耐寒基因表达分析。结果表明,随着温度的下降,12份甜玉米骨干自交系的发芽率、发芽势、发芽指数和活力指数均受到不同程度抑制,其中发芽变幅分别为82.5、75.8和62.5个百分点;方差分析结果表明,发芽率和发芽势在温度、品种及温度与品种间互作效应均存在极显著差异;在18和12℃下,8个耐低温发芽能力单项指标表明,发芽率、发芽势、发芽指数和活力指数两两之间存在显著相关,性状聚类分析将12品种分为3类,分别为耐冷型、一般型和敏感型,筛选出闽甜系T146(1-46)、闽甜系L18(L18)、12hi307(307)、闽甜系JR8609(JR86)、闽甜系AS67(AS67)、闽甜系X9034(X90)和闽甜系AG87(AG87)为具有较好的耐低温萌发能力的优势材料。针对1-46、L18、307、JR86和AS67进行幼苗低温处理,其中L18幼苗的丙二醛(MDA)含量显著低于其余4份材料,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性表现相反;抗寒基因表达分析结果发现,ZmCesA2、ZmCesA10和ZmDREB1.7在AS67和L18中表达较高,ZmMPK2在L18中表达最低;综合分析结果表明,闽甜系L18和闽甜系AS67具有较强耐低温能力。本研究结果一方面丰富了甜玉米耐寒性理论研究,另一方面为耐寒新品种选育提供了良好的材料资源。

低温弱光处理对茄子不同时期花青素含量及果实品质的影响

【目的】探究低温、弱光、低温弱光处理对茄子幼苗期、花期、果期花青素含量的影响,以及对茄子品质的影响,为茄子的优质培育以及高产栽培奠定理论基础。【方法】以紫黑茄秀娘为试验材料,分别在幼苗期、花期、果期进行低温(18℃/13℃,250μmol·m^(-2)·s^(-1))、弱光(25℃/20℃,120μmol·m^(-2)·s^(-1))、低温弱光(18℃/13℃,120μmol·m^(-2)·s^(-1))、CK(25℃/20℃,250μmol·m^(-2)·s^(-1))等4个处理,测定幼苗期形态及生理特性,不同时期、不同部位的花青素,以及果期果实的品质。【结果】低温弱光胁迫对幼苗生长存在显著影响,在幼苗期低温对幼苗生长及生理影响显著大于弱光及低温弱光,花青素含量均表现为根<叶片<叶脉<茎;在花期,花青素含量依次为花萼<花瓣;在果期,花青素含量依次为果肉<果柄<果皮。茄子不同时期受到胁迫后,不同部位的花青素含量均呈现弱光<CK<低温弱光<低温,各胁迫下果实色泽指数依次为弱光<CK<低温弱光<低温,可溶性糖含量、可溶性蛋白含量、类黄酮含量、总酚含量均呈现低温<低温弱光<弱光<CK。【结论】低温促进花青素合成;弱光抑制花青素合成;在低温弱光双因素互作下,低温因素对花青素含量的影响起主导作用,花青素的合成大于降解,花青素含量增加。低温、弱光、低温弱光胁迫下茄子品质均下降,其中,低温胁迫对茄子的品质影响最大。

50份加工型辣椒DH系苗期耐低温弱光综合评价

以前期利用花药培养技术创制的50份加工型辣椒DH系为试验材料,以SPAD值、F_(v)/F_(m)、根系直径、茎叶干质量、根系干质量、整株干质量和根冠比7个指标的耐低温弱光指数为评价指标,采用模糊隶属函数和聚类分析法对其进行耐低温弱光综合评价。结果表明:50份DH系的耐低温弱光模糊隶属函数综合指数范围在0.20~0.76之间,聚类分析可将其分为两大类,根据耐低温弱光指数特点和模糊隶属函数综合指数可确定第Ⅱ类有7份DH系为耐低温弱光材料,即H201605-8、H201604-4-1、H201612-4-1、H201605-7、H201612-4、H201605-34和H201604-18。50份加工型辣椒DH系间耐低温弱光性差异较大,可作为相关机理研究的试验材料;筛选出的7份耐低温弱光DH系为培育适合设施栽培的优良辣椒新品种提供了材料基础,也为定向培育抗非生物逆境辣椒种质新材料提供了参考。

甜菜红素稳定性的研究

本文研究了影响甜菜红素稳定性的因素。实验结果表明,随着氧化剂、还原剂、pH的增加,甜菜红素吸光度降低,甜菜红素的稳定性变差。因此,甜菜红素可以用于冰激凌等低温加工的食品中。