Effect of heat stress on the MDA, proline and soluble sugar content in leaf lettuce seedlings

High temperature stress on different varieties of lettuce seedlings in MDA, proline and soluble sugar content were studied. The results were as follows : With the stress temperature, varieties of leaf lettuce seedlings in the MDA, proline and soluble sugar content gradually increased;Different varieties had the most significant difference in 38/33℃(d/n). The increase of heat-resistant varieties on proline and soluble sugar content was quick and high, while its increase in MDA content was slow and small.

Effect of Root-Zone Temperature on Growth and Quality of Hydroponically Grown Red Leaf Lettuce (Lactuca sativa L. cv. Red Wave)

Soil temperature influences crop growth and quality under field and greenhouse conditions;however, precise investigation using controlled cultivation systems is largely lacking. We investigated effects of root-zone temperatures on growth and components of hydroponically grown red leaf lettuce (Lactuca sativa L. cv. Red Wave) under a controlled cultivation system at 20&degC. Compared with ambient root-zone temperature exposure, a 7-day low temperature exposure reduced leaf area, stem size, fresh weight, and water content of lettuce. However, root-zone heating treatments produced no significant changes in growth parameters compared with ambient conditions. Leaves under low root-zone temperature contained higher anthocyanin, phenols, sugar, and nitrate concentrations than leaves under other temperatures. Root oxygen consumption declined with low temperature root exposure, but not with root heating. Leaves of plants under low rootzone temperature showed hydrogen peroxide production, accompanied by lipid peroxidation. Therefore, low temperature root treatment is suggested to induce oxidative stress responses in leaves, activating antioxidative secondary metabolic pathways.

Synergistic Effects of a Night Temperature Shift and Methyl Jasmonate on the Production of Anthocyanin in Red Leaf Lettuce

The production of a secondary metabolite such as anthocyanin is coordinately regulated by plant intrinsic factors and influenced by multiple environmental factors. In red leaf lettuce, the red pigment component anthocyanin is important for the commercial value of the crop, but its synchronous regulation by multiple factors is not well understood. Here, we examined the synergistic effects of a night temperature shift and methyl jasmonate (MJ) on the production of anthocyanin in red leaf lettuce. Low or high night temperature treatment for 3 days just before harvesting induced the production of anthocyanin without affecting plant biomass. Temperature-dependent activation of anthocyanin accumulation was accelerated by treating with MJ. Night temperature shifts and MJ triggered oxidative stresses in leaves, as indicated by hydrogen peroxide accumulation and lipid peroxidation. Interestingly, these oxidative stresses were more evident in leaves simultaneously treated with both a high night temperature and MJ. The activity of the superoxide dismutase (SOD) was increased alongside the elevation of oxidative stress. Taken together, these results indicate that the combined treatment of a night temperature shift with MJ may accelerate anthocyanin production by increasing the levels of oxidative stress to the leaves of red leaf lettuce.

Effects of Lactoperoxidase System Activation-Oregano Essential Oilor Chlorine on the Quality of Modified Atmosphere Packaged Fresh-Cut Iceberg Lettuce

The present work focused on the effects of the Modified Atmosphere Packaging (MAP) 1 (5% O2 and 10% CO2) or 2 (2% O2 and 5% CO2) and the previous addition of Lactoperoxidase System (LPS) and Oregano essential oil or chlorine washing on the quality of fresh-cut lettuce during refrigerated storage at +4?C. Our results showed the significant effect of this combined treatment on quality improvement during storage. Thus, mesophilic bacteria was reduced in treated samples compared to those untreated with number which not exceeded the critical of 5 × 107 UFC?g-1 (p 2 and CO2 levels created by both atmosphere were not significantly different between the two treatments (p > 0.05). Brightness of lettuce samples was significantly reduced during storage. Thereafter, the PCA data showed the effect of combined treatment on the preservation of hygienic, physico-chemical and sensory quality up to the 7th day of refrigerated storage of these treated samples. The results obtained draw attention to modified atmosphere packaging lettuce and the addition of bio-preservatives which could be an alternative of choice to replace chlorine to preserve the sanitary quality of green products.

The effect of artificial solar spectrum on growth of cucumber and lettuce under controlled environment

Light-emitting diodes(LEDs)have been widely applied in the controlled environment agriculture,which are characterized by relatively narrow-band spectra and energetical efficiency.Most recently,the spectrum of Sunlike LEDs has been engineered and it closely resembles solar spectrum in the range of photosynthetic active radiation(PAR,400–700 nm).To investigate how plant growth responses to the spectrum of Sunlike LEDs,cucumber and lettuce plants were cultivated and their responses were compared with the conventional white LEDs as well as composite of red and blue LEDs(RB,R/B ratio was 9:1).We observed that although Sunlike LEDs resulted in a longer stem in cucumber,dry weight and leaf area were similar as those under RB LEDs,and significantly higher than those under white LEDs.Moreover,cucumber leaves grown under Sunlike and white LEDs showed higher photosynthetic capacity than those grown under RB LEDs.For lettuce,plants grown under Sunlike LEDs showed larger leaf area and higher dry weight than the other two treatments.However,the leaf photosynthetic capacity of lettuce grown under Sunlike LEDs was the lowest.In this context,the spectrum induced plant functions are species-dependent.Furthermore,the three types of LEDs show distinct light spectra and they are different in many aspects.Therefore,it is difficult to attribute the different plant responses to certain specific light spectra.We conclude that plants grown under Sunlike LEDs exhibit larger leaf area,which may be due to some specific spectrum distributions(such as more far-red radiation),and consequently are favorable for light interception and therefore result in greater production.

Markers for Rapid Evaluation of Virus Resistance for TYLCV in Tomato, ZYMV and PRSV-W in Zucchini and LMV in Lettuce and Hybrid Seeds in Pumpkin

Screening for the source of virus resistance in horticultural plants or specific characterization as hybridization, through symptoms, requires time and depends on the weather and knowledge of plant characteristics. So, it is important to develop specific gene markers to allow rapid diagnosis by PCR. Markers were developed based on sequences homology comparison of susceptible and resistant plants provided by HORTEC SEEDS in tomato for Tomato yellow leaf curl virus (TYLCV) by the resistance gene Ty-1, in zucchini for Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus estirpe watermelon (PRSV-W), and in lettuce for Lettuce mosaic virus (LMV). Fragments of 249 bp were amplified only by resistant plants to TYLCV as the hybrids 2648 and Aguamiel, and not for varieties as Santa Cruz or Carina. It were observed for ZYMV the amplification of 791 bp by the resistant hybrid Px7051 and not for the susceptible cultivar La Belle;for PRSV-W using the same zucchini plants the amplification of 650 bp for susceptible and 750 bp for resistant;for LMV the 421 bp amplification only for the resistant cultivar Brasil 303 and not for susceptible Babá de Verão. Finally, it was observed that primers PK47F/R were able to check the Cabotiá seed hybrids of pumpkin Jabras.

UV-B对不同品种生菜生长和品质的影响

以生菜为试材,以荧光灯为对照,采用相同功率的红∶蓝=4∶1组合光(RB)和红∶蓝∶UV-B=20∶5∶1(RBU)对绿叶、红叶、紫叶和深紫叶4个品种生菜进行全光照处理,比较不同光质处理对不同品种生菜生长、产量和品质的影响,以期探索UV-B对不同品种生菜(Lactuca sativa L.)生产的影响。结果表明:4个品种生菜均在荧光灯处理下表现最差,RBU处理下绿叶生菜在茎粗和地上鲜质量上显著低于RB处理,但绿叶生菜维生素C含量在RBU处理下显著高于RB处理,紫叶和深紫叶生菜在RBU处理下各生长指标和生物量与RB处理无显著差异,但RBU处理下二者花青素含量比RB处理显著提高。

叶用莴苣新品种云油麦1号的选育

云油麦1号是从地方品种龙岩绿叶莴苣的混杂群体中经单株系统选育而成的叶用莴苣新品种。植株生长势强,株高31~35 cm,开展度40~45 cm;叶片披针形,绿色,叶面光滑,口感脆香,品质好;单株叶片数37~40片,单株质量270~300 g,每667 m^(2)产量2400 kg左右,高抗霜霉病,耐抽薹,适合云南省滇中地区全年栽培,夏、秋保护地栽培定植至采收50~55 d(天),冬、春保护地栽培定植至采收60~65 d(天)。

基于图像处理的水培生菜冠层图像叶面积估测研究

为实现精准、高效、无损地获取植物工厂环境下水培生菜相关长势参数叶面积(Leaf area,LA),基于数字图像处理和机器学习回归方法建立单株水培生菜冠层图像LA估测模型。首先,通过智能手机获取2个生菜品种不同生长期的冠层可见光图像,利用Photoshop图像处理软件将原始图像统一剪裁为900像素×900像素大小,采用中值滤波(MedianBlur)法对剪裁后的图像进行去噪运算,将RGB图像转化为HSV颜色空间,再采用mask掩膜法分割彩色图像;然后,利用图像法获取单株生菜LA实测值,构建以LA实测值为因变量,以生菜冠层投影面积(Projected leaf area,PLA)为自变量的线性回归(Linear regression,LR)模型和以全局图像特征(颜色、形状、纹理等)为自变量的支持向量回归(Support vector regression,SVR)、多元线性回归(Multiple linear regression,MLR)和随机森林(Random forest,RF)等LA估测模型进行对比分析;最后,采用决定系数(Coefficient of determination,R^(2))和均方根误差(Root mean square error,RMSE)评估模型的准确性。结果表明:RF模型估测效果最好,对于生菜品种‘绿萝’单株LA估测结果的R^(2)为0.9714、RMSE为8.89 cm2,对于品种‘碧霄’估测结果的R^(2)为0.9201、RMSE为23.34 cm2。本研究验证了RF回归模型能够较准确地估测生菜单株叶面积,可为植物工厂水培生菜LA无损估测提供新的解决方案和研究基础。

一个预测紫叶生菜花青素含量的高光谱深度学习模型

紫叶生菜叶片内富含花青素、胡萝卜素、维生素、矿物质等元素,其中花青素作为叶片组织中的主要色素对植物提供多种修复及保护功能,其含量可反应紫叶生菜的生理状态,因此其高精度预测具有现实意义。为了高效、准确地估算紫叶生菜的花青素含量,采集了紫叶生菜的高光谱数据并开展了高精度建模研究。对原始平均反射光谱数据进行了一阶导数(FD)、二阶导数(SD)、标准正态变换(SNV)、S-G滤波和多元散射校正(MSC)五种预处理操作,基于不同预处理光谱建立紫叶生菜花青素含量的偏最小二乘回归(PLSR)模型并进行性能对比,确定MSC为理想的光谱预处理方法。针对原始光谱及经MSC预处理的光谱,使用竞争自适应重加权采样(CARS)算法分别选择特征波段,基于全波段(原始光谱、经MSC预处理光谱)和特征波段(基于原始光谱的特征波段、基于MSC预处理光谱的特征波段)分别构建PLSR模型,表现最佳的MSC-CARS-PLSR在验证集上的决定系数(R2)和均方根误差(RMSE)分别为0.872和0.070 mg·L^(-1),剩余预测偏差(RPD)为2.862。为进一步提高预测精度,本文提出一种融合深度卷积特征和极限学习机(ELM)的回归分析框架Ensemble,基于改进的Inception模块设计了与输入光谱信号匹配的一维卷积神经网络(1DCNN)作为特征提取器,采用ELM代替全连接层作为高级回归器对提取的特征进行计算。通过对比分析,Ensemble性能优于单独的1DCNN模型、ELM模型以及基于预处理光谱构建的最佳PLSR模型,其在验证集上的R2和RMSE分别为0.905和0.060 mg·L^(-1),RPD为3.319,表现出较高预测精度以及极佳的稳定性。进一步分析了预处理操作对Ensemble预测精度的影响,实验结果显示Ensemble对于预处理操作的依赖程度远小于PLSR,表明该模型同时继承了1DCNN的深度特征表示和ELM的高泛化性,能够实现基于原始光谱进行端到端的高精度花青素含量预测,为及时、准确掌握紫叶生菜长势情况提供了理论支撑。

莴苣叶中不溶性膳食纤维的提取工艺及其表征

为研究莴苣叶中不溶性膳食纤维提取的最佳工艺条件,以莴苣叶渣为原料,采用碱提法提取不溶性膳食纤维(insoluble dietary fiber,IDF)。选取NaOH浓度、液料比、提取时间和提取温度为因素,以IDF得率为指标,通过响应面法对提取工艺进行优化,并对样品进行表征及应用性能评价。结果表明,最优提取工艺条件为NaOH浓度5.5%、液料比40∶1(mL/g)、提取时间15 min、提取温度65℃,此时IDF得率为51.43%。通过傅里叶变换红外光谱仪分析可知提取的IDF是典型的膳食纤维,由纤维素、半纤维素、木质素和果胶4种主要成分组成,通过X射线衍射分析可知提取的IDF属于纤维素Ⅰ型晶体结构,通过热重分析可知提取的IDF具有更高的热解温度和更好的热稳定性。IDF的持水力和持油力均较高,分别为(5.80±0.16)g/g和(1.76±0.17) g/g。

莴笋红叶基因图位克隆及分子标记开发

【目的】研究莴笋叶色变异的遗传基础,加速莴笋新品种育种进程,提高育种效率。【方法】通过构建红叶和绿叶莴笋杂交群体,分析遗传规律,利用混池分组分析法(BSA-seq)和图位克隆法精细定位并克隆了莴笋红叶基因Lactuca sativa Red Leaf 1(LsRL1),根据变异位点设计了分子标记用于红叶莴笋分子标记辅助育种。【结果】遗传分析结果显示F2分离群体中红叶个体与绿叶个体的分离比为3∶1,说明研究中莴笋叶色表型受一个基因控制,且红叶相对于绿叶为显性性状。混池分组分析法(BSA-seq)将莴笋叶色基因LsRL1初步定位在莴笋第5染色体336.00 Mb到339.64 Mb的范围内。利用图位克隆的方法进一步将LsRL1基因的范围缩小至2个Indel分子标记ls06和ls12之间的85.17 kb区间内,这一区间内包含2个基因LOC111892298和LOC111892911。亲本间差异位点分析将LsRL1的候选基因确定为LOC111892911,该基因在拟南芥中的同源基因编码一个bHLH转录因子,参与花青素合成途径的调控。【结论】基于LsRL1基因在2个亲本间的插入缺失变异,我们开发了一个可用于红叶莴笋分子标记辅助育种的Indel标记,以加速红叶莴笋的育种进程。

光质与钾浓度交互模式对紫叶生菜生长、营养与品质的影响

为探究光质与钾浓度交互对紫叶生菜生长、品质的影响,进而筛选紫叶生菜最适光质与钾浓度交互模式。试验以‘紫罗马’紫叶生菜为试验材料,以白色荧光灯(L1)为对照,另设3种LED光质处理;同时基于Hoagland营养液配方,设置6个钾浓度处理,共24个处理。光质处理30 d后采收并测定紫叶生菜生物量、营养及品质相关指标。结果表明,不同光质与钾浓度交互模式对紫叶生菜生长、营养与品质存在一定影响。(1)生长方面,不同光质与60、90、120、150μg·mL^(-1)钾浓度交互时,对地上部鲜质量(产量)与根系总长提升效果较优者均为红光。不同钾浓度与红光、蓝光、红蓝复合光交互时,对产量、叶面积、根系总长提升效果较佳者为150μg·mL^(-1)钾浓度。而不同光质与钾浓度交互模式下,红光与150μg·mL^(-1)钾浓度交互对产量提升效果最佳,较同钾浓度的白光处理提高59.52%;蓝光与150μg·mL^(-1)钾浓度交互对株高、叶面积及根系生长存在促进作用,综合效益最佳。较同钾浓度的白光处理,蓝光与150μg·mL^(-1)钾浓度交互模式株高、叶面积、地下部鲜质量与根体积分别提高27.94%、49.06%、78.74%、169.35%。(2)营养与品质方面,不同光质与60、90、120μg·mL^(-1)钾浓度交互时,提高可溶性蛋白与可溶性糖含量效果较佳者为红光;与150、180μg·mL^(-1)钾浓度交互,各光质均可提高维生素C含量并降低硝酸盐含量。而不同钾浓度与白光、蓝光、红蓝复合光交互时,提高可溶性糖与维生素C含量效果较佳者均为150μg·mL^(-1)钾浓度。而不同光质与钾浓度交互模式下,蓝光与150μg·mL^(-1)钾浓度交互对品质指标综合提升效果最佳。较同钾浓度的白光处理,蓝光与150μg·mL^(-1)钾浓度交互模式的可溶性糖、可溶性蛋白与维生素C含量分别提高158.53%、14.07%、8.05%;而对光合色素与花青素提升效果最佳的分别为红蓝光与120μg·mL^(-1)钾浓度交互、蓝光与180μg·mL^(-1)钾浓度交互。综上所述,不同光质与钾浓度交互模式对紫叶生菜生长与品质影响不同,结合隶属函数进行综合指标评定,得出蓝光与150μg·mL^(-1)钾浓度交互为紫叶生菜最佳管理模式。而为进一步提高紫叶生菜产量,可选择红光与150μg·mL^(-1)钾浓度交互;进一步提高花青素含量,可选择蓝光与180μg·mL^(-1)钾浓度交互进行生产。

瞬时沉默LsABF2对叶用莴苣抽薹和相关基因表达的影响

【目的】为进一步探明LsABF2参与叶用莴苣抽薹过程中的分子机制,进一步了解ABA通路对叶用莴苣抽薹的影响,为未来抗抽薹叶用莴苣的育种提供理论支持。【方法】使用易抽薹叶用莴苣品种‘GB-30’为试验材料,利用VIGS技术和qRT-PCR技术分析了LsABF2基因在叶用莴苣抽薹中的作用,以及LsABF2与LsARF3、LsARF3L之间的联系。【结果】瞬时沉默LsABF2后,对植株进行株高和茎长的观察测量,经过3次技术重复、3次生物重复,发现沉默LsABF2基因24 d后的植株茎长明显高于对照组,并且具有显著性差异。制作植物茎尖的石蜡切片观察茎尖生长点形态,结果显示空白和阴性对照组植株尚未进入进入生殖生长时期,茎尖生长点位置呈现凸起状态;而试验组植株中茎尖生长点呈扁平状,表明已经开始花芽分化,进入生殖生长时期。因此,使用VIGS技术瞬时沉默LsABF2基因促进了叶用莴苣抽薹。通过荧光定量PCR技术表明LsABF2与LsARF3、LsARF3L有相互作用,LsABF2沉默后二者的表达量升高。【结论】LsABF2基因与叶用莴苣先期抽薹相关,在叶用莴苣抽薹中起抑制作用。并且验证了在叶用莴苣中生长素调节因子LsARF3、LsARF3L与脱落酸调节因子LsABF2之间有相互作用,共同调节叶用莴苣的抽薹。

去乙酰化酶LsHDAC8基因在叶用莴苣抽薹中的作用

【目的】探明LsHDAC8参与叶用莴苣高温诱导抽薹过程中的分子机制奠定基础。【方法】以‘GB-30’为试验材料,克隆LsHDAC8基因,基于其核苷酸序列,进行生物信息学分析;通过病毒诱导基因沉默技术沉默LsHDAC8基因,并通过实时荧光定量PCR(qRT-PCR)技术对沉默植株进行基因相对表达量分析。【结果】叶用莴苣LsHDAC8基因的CDS全长序列为1125 bp,共编码374个氨基酸,该蛋白的相对分子质量为40.72 kD,理论等电点为5.55,不稳定系数为28.49,脂肪族系数为85.24,属于典型的稳定性蛋白;总平均疏水性为-0.16,是亲水性蛋白;该蛋白含有3种二级结构,α螺旋(39.57%)、延伸链(16.31%)和无规则卷曲(44.12%);高温处理前8 d,LsHDAC8在花芽中的表达量显著低于对照,随着高温处理时间延长,LsHDAC8反而高于对照;LsHDAC8瞬时沉默植株的茎长明显大于空白对照组和阴性对照组,表明沉默LsHDAC8基因显著加速了叶用莴苣的抽薹。【结论】LsHDAC8基因在叶用莴苣开花抽薹过程中可能起抑制作用。

LsABF4基因在叶用莴苣抽薹中的作用分析

【目的】探明LsABF4基因在叶用莴苣高温诱导抽薹过程中的作用机制,为将来培育抗抽薹叶用莴苣品种提供理论支持。【方法】以易抽薹叶用莴苣品种‘GB-30’为材料,采用同源克隆的方法克隆出LsABF4基因,运用生物信息学软件和网站在线对基因进行比对、分析和预测编码的氨基酸序列构成、蛋白质结构等,通过病毒诱导基因沉默技术分析LsABF4基因在叶用莴苣抽薹中的作用。【结果】LsABF4基因的CDS序列全长为978 bp,共编码325个氨基酸,蛋白相对分子量为35885.21 Da,理论等电点值为9.47,不稳定指数为48.96,该蛋白为不稳定蛋白,蛋白平均疏水指数为-0.939,是亲水蛋白;该转录因子含有bZIP_plant_BZIP46保守结构域,并且其高级结构主要由α螺旋和无规则卷曲两种结构组成;对基因LsABF4瞬时沉默后,分析茎长测量数据发现,沉默组植株茎长明显高于对照组和空载组。通过石蜡切片技术对茎尖花芽分化的情况进行观察分析,结果呈现出对照组和空载组的植株茎尖生长点呈锥形,花芽尚未分化,而沉默组植株茎尖生长点呈扁平状,已进入花芽分化期。表明通过病毒诱导技术对LsABF4沉默可以促进叶用莴苣抽薹。【结论】LsABF4基因是典型的ABF转录因子,具有ABF蛋白家族的功能,对叶用莴苣抽薹过程起抑制作用。

LsABF5基因在叶用莴苣抽薹中的作用分析

【目的】为进一步探明LsABF5参与叶用莴苣高温诱导抽薹过程中的分子机制。【方法】以易抽薹叶用莴苣品种‘GB-30’为材料,采用同源克隆的方法克隆出LsABF5基因,运用生物信息学软件对其cDNA序列进行分析,并通过病毒诱导基因沉默技术分析LsABF5基因在叶用莴苣抽薹中的作用。【结果】LsABF5基因的全长CDS序列为1035 bp,共编码着344个氨基酸,理论等电点值为7.59,蛋白相对分子量为38.8 kDa;该转录因子含有bZIP保守结构域,并且其高级结构大多由α螺旋和无规则卷曲组成;通过与其他植物的ABF家族成员进行同源比对和进化分析,叶用莴苣LsABF5与刺苞菜蓟亲缘关系最接近;瞬时沉默LsABF5后,在茎长测量观察中发现,沉默LsABF5后的植株茎长明显高于空白对照组、阴性对照组。对其茎尖花芽分化情况观察分析,发现空白对照组、阴性对照组植株茎尖生长点呈锥形,花芽尚未分化,沉默组植株茎尖生长点呈扁平状,已进入花芽分化期。病毒诱导LsABF5沉默可以促进叶用莴苣抽薹。【结论】LsABF5基因是典型的ABF转录因子,具有ABF蛋白家族的功能,在叶用莴苣抽薹中起抑制作用。

冠菌素对生菜抽薹及相关生理的影响

【目的】筛选出冠菌素的最佳处理浓度抑制高温状态下生菜抽薹。【方法】采用北散生2号生菜与不同浓度冠菌素进行完全随机试验设计,以常温(清水)和高温(清水)作为对照处理,探明五种不同浓度冠菌素对北散生2号生菜的生长形态、营养品质、抗性品质和抗氧化酶活性的影响。【结果】与常温(清水)、高温(清水)处理相比,在高温状态下喷施不同浓度冠菌素的处理组北散生2号生菜的可溶性蛋白、维生素C、可溶性糖含量均呈现上升趋势,其中H2500组处理显著降低了植株茎长等生长指标,并且丙二醛、维生素E等含量等含量变化在H2500组最为明显。【结论】在高温状态下,喷施冠菌素可以抑制北散生2号生菜抽薹,其中以叶面喷施稀释2500倍冠菌素对生菜高温抽薹抑制效果最佳。

Enrichment process of lanthanum as a nonessential trace element in leaf cells of lettuce(Lactuca sativa L.)

Rare earth elements(REEs)as nonessential trace elements are enriched in living organisms and threaten their health.To early detect and reduce REE enrichment in living organisms,scientists are focused on clarifying the enrichment process of REEs in living organisms and its risks.However,the enrichment process of REEs in edible plant cells has remained unclear.Herein,by using interdisciplinary methods and techniques,the enrichment process of lanthanum(La(Ⅲ))in the leaf cells of lettuce(Lactuca sativa L.)was investigated.(1)When La(Ⅲ)exposure dose is 0.5-5μmol/L,La(Ⅲ)is enriched outside the plasma membrane(PM).In this zone,La(Ⅲ)is bound to vitronectin-like protein(VN)to form La-VN complexes;(2)When La(Ⅲ)exposure dose is 5-20μmol/L,besides the zone outside the PM,La(Ⅲ)is also enriched on the PM and bound to arabinogalactan proteins(AGPs)to form La-AGPs complexes;(3)When La(Ⅲ)exposure dose is 20-140μmol/L,besides the zone outside and on the PM,La(Ⅲ)is enriched inside the PM;(4)When La(Ⅲ)exposure dose is 60-140μmol/L,malondialdehyde content(an important indicator of invisible damage)significantly increases.Thus,as La(Ⅲ)exposure dose increases,La(Ⅲ)gradually migrates from outside the PM to the PM and inside the PM,enriching in these zones in turn.The enriched La(Ⅲ)will cause invisible damage to lettuce leaf cells and even enter human bodies along food chains.These results provide references for investigating the enrichment process of REEs in plants and its environmental risks,and finding strategies to early detect and reduce REE enrichment in plants.

二阴区紫叶莴笋新品种引进筛选试验

为提高永登县紫叶莴笋的产量和品质,提升商品价值,增加农民收入,2023年在永登县武胜驿镇旅顺村巍林农业生态科技开发有限公司生产基地开展紫叶莴笋新品种引进筛选试验,对引进的12个紫叶莴笋新品种进行田间观察记载及产量品质分析。结果表明,满地红莴苣一号和吉品红蒄2个莴笋品种在生理性状、产量品质及抗病性等方面优于其他参试品种,适宜在永登县武胜驿镇、民乐乡、坪城乡等高海拔二阴区推广种植。