Hypoglycaemia in screening oral glucose tolerance test in pregnancy with low birth weight fetus

Maternal hypoglycemia,a condition characterized by lower than normal blood glucose levels in pregnant women,has been increasingly associated with adverse pregnancy outcomes,including low birth weight(LBW)in neonates.LBW,defined as a birth weight of less than 2500 g,can result from various factors,including maternal nutrition,health status,and metabolic conditions like hypoglycemia.Maternal hypoglycemia may affect fetal growth by altering the supply of essential nutrients and oxygen to the fetus,leading to restricted fetal development and growth.This condition poses significant risks not only during pregnancy but also for the long-term health of the child,increasing the likelihood of developmental delays,health issues,and chronic conditions later in life.Research in this area has focused on understanding the mechanisms through which maternal hypoglycemia influences fetal development,with studies suggesting that alterations in placental blood flow and nutrient transport,as well as direct effects on fetal insulin levels and metabolism,may play a role.Given the potential impact of maternal hypoglycemia on neonatal health outcomes,early detection and management are crucial to minimize risks for LBW and its associated complications.Further investigations are needed to fully elucidate the complex interactions between maternal glucose levels and fetal growth,as well as to develop targeted interventions to support the health of both mother and child.Understanding these relationships is vital for improving prenatal care and outcomes for pregnancies complicated by hypoglycemia.

Association of hypoglycaemia in screening oral glucose tolerance test in pregnancy with low birth weight fetus

BACKGROUND Gestational diabetes mellitus(GDM) is a common metabolic derangement in pregnant women. In the women identified to be at high risk of GDM, a 75 g oral glucose tolerance test(OGTT) at 24-28 wk gestation is the recommended screening test in the United Kingdom as per National Institute for Health and Care Excellence(NICE). Hypoglycaemia following the glucose load is often encountered and the implication of this finding for the pregnancy, fetus and clinical care is unclear.AIM To determine the prevalence of hypoglycaemia at any time during the screening OGTT and explore its association with birth weight.METHODS All deliveries between 2009 and 2013 at the local maternity unit of the University hospital were reviewed. Of the total number of 24,154 women without preexisting diabetes, those who had an OGTT for GDM screening based on NICE recommended risk stratification, who had a singleton delivery and had complete clinical and demographic data for analysis, were included for this study(n =3537). Blood samples for fasting plasma glucose(FPG), 2-hour plasma glucose(2-h PG) and HbA1 c had been obtained. Birth weight was categorised as low(≤ 2500 g), normal or Macrosomia(≥ 4500 g) and blood glucose ≤ 3.5 mmol/L was used to define hypoglycaemia. Binary logistic regression was used to determine the association of various independent factors with dichotomized variables; the differences between frequencies/proportions by χ~2 test and comparison between group means was by one-way ANOVA.RESULTS Amongst the study cohort(3537 deliveries), 96(2.7%) women had babies with LBW(< 2500 g). Women who delivered a LBW baby had significantly lower FPG(4.3 ± 0.6 mmol/L, P = 0.001). The proportion of women who had a 2-h PG ≤ 3.5 mmol/L in the LBW cohort was significantly higher compared to the cohorts with normal and macrosomic babies(8.3% vs 2.8% vs 4.2%; P = 0.007). The factors which predicted LBW were FPG, Asian ethnicity and 2-h PG ≤ 3.5 mmol/L,whereas maternal age, 2-h PG ≥ 7.8 mmol/L and HbA1c were not significant predictors.CONCLUSION A low FPG and 2-h PG ≤ 3.5 mmol/L on 75-gram OGTT are significantly associated with low birth weight in women identified as high risk for GDM.Women of ethnic backgrounds(Asians) appear to be more susceptible to this increased risk and may serve as a separate cohort in whom we should offer more intensive follow up and screening for complications. Cost implications and resources for follow up would need to be looked at in further detail to support these findings.

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.

Phosphorus Nutrient Characteristics of Different Maize (Zea mays L.) Inbreds for Tolerance to Low-P Stress

Phosphorus nutrient characteristics of different maize inbred lines to low-P stress were studied at stages of seedling, steming, earing, silking under pot culture. In the periods of seedling and steming, P uptake efficiency was the main contributor to P tolerance, and the relative P content in P-tolerant genotypes, 99180 and 99239 were higher than that in sensitive genotype, 99152. At earing stage, P-tolerant genotypes, compared to P-sensitive ones, had higher accumulation of P in upper leaves. When came to the silking stage, P uptake and redistribution efficiency of P-tolerant genotypes were higher than those in 99152. The results also suggested that there are different mechanisms of P nutrient uptake and distribution in different P-tolerant genotypes. Inbred line 99239, according to the investigation, was considered as an efficient stock in the P-uptake while 99180 fallen to the efficient stock of P redistribution.

A high salt tolerance and low adsorption drag reducer based on non-covalent enhancement

To formulate fluids with flowback water,produced water directly to improve the utilization rate of recycling and reduce the adsorption damage of slick water to reservoirs,a high salt tolerance and low adsorption drag reducer was designed and prepared by introducing polar cation fragments to enhance the non-covalent interactions between the chains.The drag reducer was characterized by IR and NMR.Friction resistance and viscosity tests were conducted to evaluate its salt resistance property.Static adsorption and dynamic adsorption retention tests were carried out to evaluate the damage of this reducer to shale reservoirs.The introduction of cation units into the molecular structure can weak the shielding effect of metal cations to some extent,so the drag reducer can keep a stable molecular structure and good resistant reducing performance under high salinity.The enhancement of non-covalent interaction between chains decreased the free polarity sites,further reduced the possibility of hydrogen bonding between drag reducer molecules and shale.In high salinity condition,both the adsorption capacity of the drag reducer on the shale surface and the average damage rate to the core permeability are low.Compared with the conventional salt-tolerant system,the overall liquid cost was reduced by 17%and the production per well increased by 44%.The application of this slick water system has achieved remarkable results.

Genetic Analyses of Tolerance to Low Nitrogen in Tropical Maize Germplasm

Six tropical maize inbred lines were crossed in a half diallel fashion and evaluated along with their F1 hybrids under low N (0 kg/ha) and high N(170 kg/ha), for grain yield, ear diameter, ear length, number of rows per ear, 100-kernel weight, ear leaf area, shoot dry weight, ear leaf chlorophyll content and plant height to determine their response to different level of N. Grain yield and ear leaf chlorophyll content measured by 48% lower under -N than under + N, and were most affected by -N. Ear length had the highest reduction under -N of 22%. Plant height and shoot dry weight were both reduced by 28%. Diallel analysis indicated significant additive as well as dominance variance for grain yield under -N. The same results were shown when one tolerant x nontolerant cross from the diallel hybrids was subjected to generation mean analysis which also indicated significant epistatic effects. These results suggest that S1 or S2 progeny selection may be an effective means of improving grain yield of tropical maize under low soil N.

Digging out molecular markers associated with low salinity tolerance of Nannochloropsis oceanica through bulked mutant analysis

Nannochloropsis oceanica is a marine microalgal species with both economic value and biological importance.It grows fast,contains rich oils,reproduces asexually,holds a small and haploidy genome,and is easy to be modified genetically.However,the genetic study of N.oceanica is scarce.Very less genetic bases of its traits have been deciphered,and no gene has been isolated from it with the function verified simultaneously via either genetic or reverse genetic approaches or both(de novo cloned).Changing medium salinity may aid to control harmful organisms met during large scale cultivation.As a stress,it may also facilitate the accumulation of desirable chemicals including fatty acids.In order to decipher the genetic basis of the low salinity tolerance of N.oceanica,we mutated N.oceanica with Zeocin.In total,five mutant bulks were constructed at equal number of cells,100 mutants each,which were tolerant to a discontinuous serial of salinities from that of 100%of f/2 to that of a mixture of 4%of f/2 and 94%of BG11.The bulks were genotyped through whole genome re-sequencing and analyzed with bulked mutant analysis(BMA)newly modified from bulked segregant analysis(BSA).In total,47 SNPs and 112 InDels were found to associate with the low salinity tolerance,and around them a set of low salinity tolerance associating genes were identified.A set of annotatable genes commonly found between control and different salinities indicated that the genes functioning in gene expression,energy metabolism and cellular structure may be involved in the low salinity tolerance.These associating molecular markers and genes around them were not enough for outlining the physiological mechanism underlining the tolerance;however they should aid to improve N.oceanica genetically.

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.

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.

GmPHR1, a Novel Homolog of the AtPHR1 Transcription Factor, Plays a Role in Plant Tolerance to Phosphate Starvation

GmPHR1 from soybean （Glycine max） was isolated and characterized. This novel homolog of the AtPHR1 transcription factor confers tolerance to inorganic phosphate （Pi）-starvation. The gene is 2 751 bp long, with an 819-bp open reading frame and ifve introns. Analysis of transcription activity in yeast revealed that the full-length GmPHR1 and its C-terminal activate the reporter genes for His, Ade and Ura, suggesting that the C-terminal peptide functions as a transcriptional activator. Quantitative real-time PCR indicated that patterns of GmPHR1 expression differed. For example, under low-Pi stress, this gene was quickly induced in the tolerant JD11 after 0.5 h, with expression then decreasing slowly before peaking at 12-24 h. By contrast, induction in the sensitive Niumaohuang （NMH） was slow, peaking at 6 h before decreasing quickly at 9 h. GmPHR1 showed sub-cellular localization in the nuclei of onion epidermal cells and Arabidopsis roots. Growth parameters in wild-type （WT） Arabidopsis plants as well as in overexpression （OE） transgenic lines were examined. Under low-Pi conditions, values for shoot, root and whole-plant dry weights, root to shoot ratios, and lengths of primary roots were signiifcantly greater in OE lines than in the WT. These data demonstrate that GmPHR1 has an important role in conferring tolerance to phosphate starvation.

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.

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.

Evaluation of Cold Tolerance in Wild Sugarcane Germplasm Resources under Field Conditions

In January 2016, Kunming underwem 52 hours of rain and snow weather below 0℃. in order to identify the cold tolerance of different wild sugarcane germplasm resources in low temperature and snow disasters, cold injuries of 38 shares of wild sugareane germplasm resources, which were oollected during 2012 -2013 and preserved in the germplasm resource nursery of Sugarcane Research Institute, Yumlan Agricultural University, were surveyed to evaluate the cold tolerance based on sugarcanc cold tolerance index （CTI） = 0.5 x shoot tip growing point injury index ＋ O. 3 x node injury index ＋ 0.2X internode injury in- dex. The results showed that cold tolerance indexes of four wild sugarcane varieties demonstrated a descending order of Erianthus arundinaceum Retz. （0.7）, Eri- aTrthus rockii Keng （0.5） , Sacchartun sporrtanettm L. （0.3） , Erianlhus fulvus Ne^s. （0）. Greater cold tolerance indexes indicate poorer cold tolerance. Thus, Erianthu, arundinaceum had the poorest cold tolerance, while Erianthus fulvus exhibited the strongest cold tolerance. In addition, there were significant differences in cold tolerance among diffcrent Saccharum spontaneum clones. The 23 Saccharum spontaneum clones could be divided into four grades, including 1 clone with the poorest cold tolerance that accounted for 4.3%, 5 clones with poor cold tolerance that accounted for 21.7%, 14 clones with strong cold tolerance that accounted tot 60.9%, and 3 clones with the strongest cold tolerance that accounted for 13.0% （2012 -23, 2012 -32, 2012 -37）. Especially, 2012 -23 exhibited extremely strong cold tolerance. This study provided the scientific basis for screening of cold-tolerant wild sugarcane germplasm resources and selection of cold-toleranl parents.

Study on Cold Tolerance Identification Indices for Bitter Gourd Germplasms

The selection of cold tolerance identification indices for bitter gourd germplasms is an important basis for the breeding of cold-tolerant bitter gourd varieties. In this study, with six bitter gourd germplasms as experimental materials, the cold injury index of bitter gourd was analyzed under low temperature treatment, the changes in physiological indices were revealed, and the main agronomic traits were measured. The results showed that the cold injury index of bitter gourd was in very significant negative correlation with SOD activity, POD activity and PRO content, in significant negative correlation with CAT activity, in very significant negative correlation with flowering node and commodity rate, but in significant positive correlation with female flower ratio. It was found that that cold injury index, SOD activity, POD activity, CAT activity and PRO content could serve as the cold tolerance identification indices for bitter gourd at seedling stage, and flowering node and commodity rate could be used as the auxiliary indices for field cold tolerance identification.

Cold tolerance of subtropical Porites lutea from the northern South China Sea

Marginal scleractinian corals growing at their latitudinal limits should be quite sensitive to variations in winter sea surface temperatures(SSTs). An extreme cold event occurring in early 2008 offered a unique opportunity to examine the effect of cold-water anomalies on Porites lutea corals and their physiological tolerance and acclimation in the subtropical northern South China Sea(NSCS). Besides in-situ observation, a subsequent aquarium-based experiment was designed for reproducing the chilling process and a 50-year-long Sr/Ca ratio profile from two P. lutea skeletal slabs was analyzed for reconstructed the historical annual minimum SSTs which ceased Porites calcification. The 2008 low-temperature anomaly caused the minimum daily mean SSTs dropped below 13°C in the Daya Bay. The stress symptoms displayed by local P. lutea colonies included polyp retraction, reduced coloration and pale, but none showed tissue sloughing. The ability of P. lutea to survive implied its tolerance of extreme low temperatures. Here we suggest a model on the tolerance of high-latitude Porites under low-temperature stresses, which is when SSTs drop below 18°C, Porites corals contract their tentacles(losing heterotrophic capability), then cease calcification(reducing energy consumption), and meanwhile maintain relatively high levels of zooxanthellae density(sustaining host’s life via photosynthetic capacity of symbiotic zooxanthellae). This study revealed remarkable acclimatization of P. lutea corals to low temperature extremes. This acclimatization is beneficial for Porites corals in the NSCS to expand their living ranges towards the higher-latitude areas and have the potential to be the incipient reef former.

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.

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。