化学感受蛋白(chemosensory proteins，CSPs)在昆虫体内发挥多种功能。为了明确丽蚜小蜂化学感受蛋白EforCSP3是否在其寄主定位和寄主选择性方面发挥嗅觉识别作用，本研究从丽蚜小蜂中鉴定到化学感受蛋白EforCSP3，并对其进行了基因表达、配体结合和分子对接试验。结果表明，EforCSP3在丽蚜小蜂雌蜂头部高表达，成虫期该基因的相对表达量显著高于其他发育时期；荧光竞争结合试验发现EforCSP3与多种寄主植物挥发物之间具有较高的结合力，其中，除月桂烯和α-律草烯外，还有邻苯二甲酸二丁酯、1-辛烯、β-榄香烯和十三烷，均与EforCSP3的结合力最强，这些组分具有被开发为丽蚜小蜂引诱剂的潜力；进一步通过蛋白质结构建模和分子对接预测了可能参与挥发物结合的EforCSP3关键氨基酸残基。结合此前的研究，α-葎草烯和β-月桂烯已被证明可以吸引丽蚜小蜂，本研究亦发现二者与EforCSP3有强的结合力。总之，EforCSP3可能参与丽蚜小蜂的化学信息识别接收过程。

早花能促进美洲南瓜早熟和高产，并能拮抗生物和非生物胁迫，是美洲南瓜重要的农艺性状。在本研究中，美洲南瓜自交系‘19’的第一雌花开花天数明显少于自交系‘113’，表现为稳定的早花性状。遗传分析表明，第一雌花开花天数是一个可遗传的数量性状，受多基因控制。采用QTL测序结合连锁分析的方法，在第4、11和20号染色体上鉴定出3个用于第一雌花开花天数的QTL。为了验证这一结果，利用不同环境条件下生长的F₂群体，开发InDel标记对第一雌花开花天数进行QTL定位分析。利用R/qtl软件的复合区间作图方法，在所有环境条件下均鉴定出1个主位点，位于20号染色体117 kb的候选区域。通过基因注释、基因序列比对和qRT-PCR分析，发现编码环指蛋白的Cp4.1LG20g08050基因可能是一个对美洲南瓜早花起相反调控作用的候选基因。总之，本研究结果为更好地认识美洲南瓜早花性状，为美洲南瓜的早花育种策略奠定了基础。

本研究的目的是确定SLC15A4在胞壁酰二肽（MDP）介导的奶牛瘤胃上皮细胞（BRECs）炎症反应中的作用。首先，检测了10 μg mL^-1 MDP处理后BRECs中促炎因子mRNA表达量的变化。RT-qPCR结果显示，在MDP刺激下，促炎因子（IL-1β、IL-6和TNF-α）的mRNA表达量显著增加（P < 0.001）。此外，通过慢病毒包装、转染、筛选和细胞单克隆培养获得了SLC15A4-KO细胞系。为了进一步了解SLC15A4的潜在功能，我们利用转录组数据揭示了野生型BRECs和SLC15A4-KO之间的基因变化。鉴定出5个下调的促炎基因和13个下调的趋化因子基因与炎症反应有关。同时，下调的基因主要富集在NF-κB和MAPK信号通路中。RT-qPCR的结果也证实了这些变化。为了进一步确定WT和SLC15A4-KO BREC如何参与炎症反应的机制，我们研究了添加MDP后BRECs的炎症反应。与对照相比，添加10 μg mL^-1 MDP处理WT BREC和SLC15A4-KO后，我们的研究结果表明，与野生型BRECs相比，SLC15A4-KO BRECs降低了炎症反应中（IL-6、TNF-α、CXCL2、CXCL3、CXCL9和CCL2）和蛋白质（p-p65和p-p44/42）的mRNA表达量（P < 0.05）。在本实验中，CRISPR-Cas9系统用于敲除奶牛瘤胃上皮细胞中的SLC15A4基因，其作用通过MDP诱导的BRECs炎症反应得到证实。这项工作将为研究MDP的促炎机制及其在奶牛亚急性瘤胃酸中毒防治工作中的应用提供理论依据。

To cope with a highly heterogeneous light environment, photosynthesis in plants can be regulated systemically.  Currently, the majority of studies are carried out with various plants during the vegetative growth period.  As the reproductive sink improves photosynthesis, we wondered how photosynthesis is systemically regulated at the reproductive stage under a vertically heterogeneous light environment in the field.  Therefore, changes of light intensity within canopy, chlorophyll content, gas exchange, and chlorophyll a fluorescence transient were carefully investigated at the graining stage of maize under various planting densities.  In this study, a high planting density of maize drastically reduced the light intensities in the lower canopy, and increased the difference in vertical light distribution within the canopy.  With the increase of vertical heterogeneity, chlorophyll content, light-saturated photosynthetic rate and the quantum yield of electron transport in the ear leaf (EL) and the fourth leaf below the ear (FLBE) were decreased gradually, and the ranges of declines in these parameters were larger at FLBE than those at EL.  Leaves in the lower canopy were shaded artificially to further test these results.  Partial shading (PS) resulted in a vertically heterogeneous light environment and enhanced the differences in photosynthetic characteristics between EL and FLBE.  Removing the tassel and top leaves (RTL) not only improved the vertical light distribution within the canopy, but also reduced the differences in photosynthetic characteristics between the two leaves.  Taken together, these results demonstrated that maize plants could enhance the vertical heterogeneity of their photosynthetic function to adapt to their light environment; slight changes of the photosynthetic function in EL at the graining stage under a vertically heterogeneous light environment indicated that the systemic regulation of photosynthesis is weak at the graining stage.

玉米收获时籽粒含水率高是中国东北高纬度地区玉米生产面临的重要问题，这与品种熟期、区域气候条件以及栽培管理技术密切相关。延迟至冬季收获不能有效降低籽粒含水率以解决上述问题。2016至2017年，在黑龙江省大庆市试验点，连续观测了不同成熟型玉米品种生理成熟后籽粒田间干燥情况。采用两段线性模型对籽粒含水率与外界气象因子进行了阶段性分析。1)两段线性模型可以将各品种的籽粒干燥过程划分为两个不同斜率的单独线性干燥过程，且拟合精度良好。2)快速干燥阶段，温度越高，干燥速度越快。而大气水汽压条件对慢速干燥过程的速率有影响。3)干燥速率由快速干燥阶段转为慢速干燥阶段时的籽粒含水率以及气象因子在品种和年份之间不一致，这两者并非是干燥速率明显变化的关键因素。但霜冻后，气温<0℃会显著降低籽粒干燥速率。4)早熟品种生育期短，干燥时间得以延长，籽粒含水率显著低于中晚熟品种。由于气温下降迅速，籽粒的干燥速率显著降低，中晚熟品种难以在田间干燥至较低的含水率水平。因此，更换早熟品种并实施相应的栽培技术是解决高含水率问题的可行途径。

玉米机械粒收破碎率高是影响粒收质量的重要因素，本试验利用研磨法测试玉米子粒破碎对水分的敏感性，探寻玉米子粒破碎率最低的含水率，并对品种耐破碎性进行评价。在北京和新乡两个试点分不同播期种植17个玉米品种，系统测试子粒水分动态变化，并利用研磨法同步进行子粒破碎率测试，分析破碎率与含水率的相关关系。北京试点和新乡试点及两地总体样本子粒含水率 (x) 与破碎率 (y) 关系均符合二次曲线 (y=ax²+bx+c) 关系，其中，两地512个样本拟合方程为y=0.0796x²-3.3929x+78.779(R²=0.2646，n=512) ，由方程拟合可见，最低破碎值为42.62%，对应的子粒含水率为21.31%；设置90%的置信区间，子粒破碎率最低的含水率范围为19.7%-22.3%，与田间机械粒收最低破碎率出现的含水率值一致。以破碎率值最低点为界发现，在低含水率条件下，破碎率与含水率呈显著线性负相关；在高含水率条件下，破碎率与含水率呈显著线性正相关；由拟合曲线(y=ax+b)斜率和相关度可见，在子粒高含水率条件下，子粒破碎对水分的敏感性更强，相关度更高。利用各品种子粒破碎率与含水率二次曲线的积分值评价不同品种子粒破碎敏感性评价方法，在北京试点筛选出耐破碎性强的品种为郑单958和丰垦139，易破碎品种包括联创825、吉单66、利单295和京农科728；在新乡试点筛选出耐破碎品种为禾田1号、郑单958和丰垦139，易破碎品种包括泽玉8911、迪卡653和京农科728。两地共用的6个品种分类结果基本一致。以上结果表明，研磨法是一种稳定性较高的检测方法，可以用于品种破碎对水分敏感性和耐破碎性评价，为耐破碎玉米品种的选育与筛选提供支持。

玉米田间籽粒收获相对于穗收能够节省后续运输、晾晒和脱粒等环节的人工成本，然而粒收后籽粒含水率出现升高的现象，降低了籽粒品质。为明确收获前后籽粒含水率差异的原因，本研究利用黄淮海平原多年多点玉米粒收试验以及在籽粒不同含水率阶段的分期收获试验，观测收获前、后籽粒含水率，破碎率，杂质率以及植株各器官含水率。在多年多点试验中，411组测试样本表明，粒收作业后籽粒含水率较收获前含水率值平均高出2.2%。分期收获试验结果表明，当收前籽粒含水率低于23.9%时，收获前、后测试结果没有显著差异，而当收前含水率高于23.9%后，收获后籽粒含水率测试值显著升高；收获后籽粒含水率增加值与收前籽粒含水率、破碎率、杂质率呈极显著正相关。通常，黄淮海夏玉米区收获期植株成熟度低、籽粒含水率高，造成较多的破碎和杂质，进而导致收获后籽粒含水率测试值升高。因此，我们建议选择生育后期植株落黄快的品种，并适当延迟收获期，降低收前籽粒含水率，从而降低破碎率和杂质率，提高收获后籽粒品质，推动中国玉米粒收发展。

类受体蛋白激酶（Receptor-like kinases, RLKs）对于植物响应非生物胁迫至关重要。丙酮醛（Methylglyoxal, MG）作为一种细胞内源代谢产物，通常被认为是一种逆境信号分子。然而，关于RLK和MG之间的关系确知之甚少。本研究中，我们阐述了一个类受体蛋白激酶OsASLRK调控水稻MG响应和内源MG含量的功能。首先，我们发现OsASLRK基因启动子区域含有一个典型的MG反应元件（AAAAAAAA）。定量RT-PCR分析表明，OsASLRK转录水平的表达以时间和剂量依赖性方式显著受外源MG的诱导。GUS染色同样证实，外源MG处理可显著增强水稻根中OsASLRK的表达。遗传学分析表明，Osaslrk突变体表现出对外源MG敏感性增强，并且在外源MG处理下内源MG含量上升，而过表达OsASLRK的水稻植株表现出相反的表型。DAB染色，氧化清除酶活性和GSH含量测定表明，OsASLRK通过提高抗氧化酶活性和减轻膜损伤来调节MG敏感性和含量变化。因此，该研究结果为阐明水稻类受体蛋白激酶OsASLRK调控MG的功能提供了新证据。

The uneven distribution of solar radiation is one of the main reasons for the variations in the yield gap between different regions in China and other countries of the world. In this study, different solar radiation levels were created by shading and the yield gaps induced by those levels were analyzed by measuring the aboveground and underground growth of maize. The experiments were conducted in Qitai, Xinjiang, China, in 2018 and 2019. The maize cultivars Xianyu 335 (XY335) and Zhengdan 958 (ZD958) were used with planting density of 12×10⁴ plants ha^–1 under either high solar radiation (HSR) or low solar radiation (LSR, 70% of HSR). The results showed that variation in the solar radiation resulted in a yield gap and different cultivars behaved differently. The yield gaps of XY335 and ZD958 were 8.9 and 5.8 t ha^–1 induced by the decreased total intercepted photosynthetically active radiation (TIPAR) of 323.1 and 403.9 MJ m^–2 from emergence to the maturity stage, respectively. The average yield of XY335 was higher than that of ZD958 under HSR, while the average yield of ZD958 was higher than that of XY335 under LSR. The light intercepted by the canopy and the photosynthetic rates both decreased with decreasing solar radiation. The aboveground dry matter decreased by 11.1% at silking and 21% at maturity, and the dry matter of vegetative organs and reproductive organs decreased by 9.8 and 20.9% at silking and by 12.1 and 25.5% at physiological maturity, respectively. Compared to the HSR, the root weights of XY335 and ZD958 decreased by 54.6 and 45.5%, respectively, in the 0–60 cm soil layer under LSR at silking stage. The aboveground and underground growth responses to different solar radiation levels explained the difference in yield gap. Selecting suitable cultivars can increase maize yield and reduce the yield gaps induced by variation of the solar radiation levels in different regions or under climate change.

Yield gap exists because the current attained actual grain yield cannot yet achieve the estimated yield potential. Chinese high yield maize belt has a wide span from east to west which results in different solar radiations between different regions and thus different grain yields. We used multi-site experimental data, surveyed farmer yield data, the highest recorded yield data in the literatures, and simulations with Hybrid-Maize Model to assess the yield gap and tried to reduce the yield gap by matching the solar radiation and plant density. The maize belt was divided into five regions from east to west according to distribution of accumulated solar radiation. The results showed that there were more than 5.8 Mg ha^–1 yield gaps between surveyed farmer yield and the yield potential in different regions of China from east to west, which just achieved less than 65% of the yield potential. By analyzing the multi-site density experimental data, we found that the accumulated solar radiation was significantly correlated to optimum plant density which is the density with the highest yield in the multi-site density experiment (y=0.09895x–32.49, P<0.01), according to which the optimum plant densities in different regions from east to west were calculated. It showed that the optimum plant density could be increased by 60.0, 55.2, 47.3, 84.8, and 59.6% compared to the actual density, the grain yield could be increased by 20.2, 18.3, 10.9, 18.1, and 15.3% through increasing plant density, which could reduce the yield gaps of 33.7, 23.0, 13.4, 17.3, and 10.4% in R (region)-1, R-2, R-3, R-4, and R-5, respectively. This study indicates that matching maize plant density and solar radiation is an effective approach to reduce yield gaps in different regions of China.

本研究2017年和2018年的种植密度为12.0×10⁴ 株 ha^-1，在施氮量为0-450 kg ha^-1范围内设置4种不同氮肥处理；2019年种植密度分别为7.5×10⁴和12.0×10⁴ 株 ha^-1，在施氮量为0-765 kg ha^-1范围内设置18种不同氮肥处理。通过测定不同处理下玉米生育期、绿叶的叶面积指数（LAI）、籽粒含水量和籽粒脱水率指标，阐明施氮量对玉米籽粒含水量的影响。结果表明，施氮量从0增加到765 kg ha^-1，玉米吐丝期推迟约1天，成熟期推迟约1-2天。在生理成熟期和生理成熟期后，不同施氮量处理下籽粒含水量极差为1.9-4.0％。随着施氮量的增加，生理成熟后玉米籽粒的脱水率降低，但施氮量与籽粒脱水率之间没有统计学意义。生理成熟期叶面积指数与生理成熟后籽粒脱水速率之间无显著相关性。总之，施氮对玉米生理成熟期和成熟后籽粒含水量均有影响，但不同施氮量对籽粒含水量的影响较小。以上结果表明，在生产中不需要考虑施氮对玉米籽粒含水量的影响。

Increasing plant density is an effective way to enhance maize yield, but often increases lodging rate and severity, significantly elevating the risk and cost of maize production.  Therefore, lodging is a major factor restricting future increases in maize yield through high-density planting.  This paper reviewed previous research on the relationships between maize lodging rate and plant morphology, mechanical strength of stalks, anatomical and biochemical characteristics of stalks, root characteristics, damage from pests and diseases, environmental factors, and genomic characteristics.  The effects of planting density on these factors and explored possible ways to improve lodging resistance were also analyzed in this paper.  The results provide a basis for future research on increasing maize lodging resistance under high-density planting conditions and can be used to develop maize cultivation practices and lodging-resistant maize cultivars.

DNA methyltransferases (Dnmts) comprise a family of proteins which involved in the establishment and maintenance of DNA methylation patterns.  In pig, the molecular characterization and tissue expression profile of Dnmt gene family are not clear.  To solve this problem, reverse transcriptase PCR and rapid amplification of cDNA ends were used to clone the sequences of the porcine Dnmt2 and Dnmt3b genes.  Furthermore, the mRNA expression profiles of Dnmt1, Dnmt2, Dnmt3a and Dnmt3b genes from 54 adult tissues and 2 entire fetuses of Rongchang pig were analyzed by quantitative real-time PCR (qRT-PCR).  As a result, the lengths of porcine Dnmt2 and Dnmt3b gene cDNAs were 1 227 and 2 559 bp with cytosine-C5 specific DNA methylase domain, respectively.  The four Dnmt genes were highly expressed in longissimus dorsi muscle (P<0.01).  Dnmt1 is highly expressed in heart (P<0.01) and Dnmt 2 shows its preference in liver and seminal vesicle tissue (P<0.01).  Dnmt3a and Dnmt3b are highly expressed in the two fetus stages (P<0.01).  All these results suggested that each gene has its specific expression profile, and deeper study is required to dig more details between the methylation level and Dnmt family mRNA expressions in different tissues.

Ten populations of Radopholus similis from different ornamental hosts were tested for their parasitism and pathogenicity to water spinach (Ipomoea aquatic), malabar spinach (Basella rubra), and squash (Cucurbita moschata) in pots. The results showed all three plants were new hosts of R. similis. Growth parameters of plants inoculated with nematodes were significantly lower than those of healthy control plants. All R. similis populations were pathogenic to the three plants, but pathogenicity differed among populations from different hosts. The same R. similis populations also showed different pathogenic effects in the three different plants. RadN5 population from Anthurium andraeanum had the highest pathogenicity to the three studied plants. RadN1 from A. andraeanum had the lowest pathogenicity to squash and RadN7 from Chrysalidocarpus lutesens had the lowest pathogenicity to water spinach and malabar spinach. R. similis is usually associated with root tissues, but here we report that it could be found to move and feed in the stem bases of all three studied plants. Sequence and phylogenetic analyses of DNA markers of the 18S rRNA, 28S rRNA, ITS rRNA, and mitochondrial DNA gene sequences of ten R. similis populations revealed significant genetic diversity. RadN5 and RadN6 populations from anthurium showed a close genetic relationship and could be distinguished from other populations by PCR-RFLP. At the same time, RadN5 and RadN6 populations were the most pathogenic to three studied plants. These results confirm the existence of large biological variability and molecular diversity among R. similis populations from the same or different hosts, and these characteristics are related to pathogenic variability.

Locating of important agronomic genes onto chromosome is helpful for efficient development of new wheat varieties. Wheat chromosome substitution lines between two varieties have been widely used for locating genes because of their distinctive advantages in genetic analysis, compared with the aneuploid genetic materials. Apart from the substituted chromosome, the other chromosomes between the substitution lines and their recipient parent should be identical, which eases the gene locating practice. In this study, a set of chromosome substitution lines with cv. Wichita (WI) as the recipient parent and cv. Cheyenne (CNN) as the donor parent were studied for the composition of high molecular weight glutenin subunits (HMW-GS) as well as a range of agronomic important traits. Results revealed that the substitution lines of WI(CNN5D), WI(CNN6A) and WI(CNN7B) had higher plant heights than the two parents of WI and CNN, and WI(CNN3D) had later maturity than the parents. By sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis, a substitution line WI(CNN5B) was found to contain different HMW-GS patterns from its two parents, in which 1By9 was replaced by 1By8 on chromosome 1BL. Simple sequence repeat (SSR) analysis confirmed that the variation on 1BL in WI(CNN5B) was originated from Chinese Spring (CS). It is concluded that chromosomal fragments from bridge material and donor parent were quite often retained in intracultivaral chromosome substitution lines except the substituting chromosomes.

This study investigates the optimal reinsurance for crop insurance in China in an insurer’s perspective using the data from Inner Mongolia, Jilin, and Liaoning, China. On the basis of the loss ratio distributions modeled by AnHua Crop Risk Evaluation System, we use the empirical model developed by Tan and Weng (2014) to study the optimal reinsurance design for crop insurance in China. We find that, when the primary insurer’s loss function, the principle of the reinsurance premium calculation, and the risk measure are given, the level of risk tolerance of the primary insurer, the safety loading coefficient of the reinsurer, and the constraint on reinsurance premium budget affect the optimal reinsurance design. When a strict constraint on reinsurance premium budget is implemented, which often occurs in reality, the limited stop loss reinsurance is optimal, consistent with the common practice in reality. This study provides suggestions for decision making regarding the crop reinsurance in China. It also provides empirical evidence for the literature on optimal reinsurance from the insurance market of China. This evidence undoubtedly has an important practical significance for the development of China’s crop insurance.

This paper aims to evaluate the effectiveness of the Chinese crop insurance program in terms of farmers’ utility and welfare. A simulation model based on the power utility function was first developed to evaluate the effectiveness of crop insurance. Then, the Monte Carlo approach was used to generate the datasets of area, price, yield, cost, and income based on the characteristics of representative farmers, which were clustered and calibrated using the farm-level data of 574 individual farmers from five Chinese provinces. Finally, the effectiveness of Chinese crop insurance was evaluated by comparing the certainty equivalence (CE) of farmers’ utility/welfare under alternative crop insurance scenarios. Government subsidy is a necessary premise for implementing the crop insurance program. The government should subsidize more than 50% of the crop insurance premium to motivate more farmers to participate in the program. The findings also show that the current crop insurance program in China has increased the farmers’ welfare but still need to be improved to achieve the Pareto improvement and to make full use of the financial fund of the government. This paper is believed to not only extend academic research but also has significant implications for policymakers, especially in the context of rapid development of Chinese crop insurance with much issues such as rate, subsidy and coverage level needed to be improved.

The regeneration rate of wheat immature embryo varies among genotypes, howbeit many elite agriculture wheat varieties have low regeneration rates. Optimization of tissue culture conditions and attempts of adding signal molecules are effective ways to increase plant regeneration rate. Inter-culture is one of ways that have not been investigated in plant tissue culture. Moreover, the use of arabinogalactan proteins (AGPs) and hydrogen peroxide (H2O2) have been reported to increase regeneration rate in a few plant species other than wheat. The current research pioneeringly uses inter-culture of immature embryos of different wheat genotypes, and also investigates impacts of AGP and H2O2 on the induction of embryogenic calli and plant regeneration. As a result, high-frequency regeneration wheat cultivars Kenong 199 (KN199) and Xinchun 9 (XC9), together with low-frequency regeneration wheat line Chinese Spring (CS), presented striking increase in the induction of embryogenic calli and plant regeneration rate of CS through inter-culture strategy, up to 52.19 and 67.98%, respectively. Adding 50 to 200 mg L–1 AGP or 0.005 to 0.01 ‰ H2O2 to the callus induction medium, enhanced growth of embryogenic calli and plant regeneration rate in quite a few wheat genotypes. At 50 mg L–1 AGP application level in callus induction medium plant regeneration rates of 8.49, 409.06 and 283.16% were achieved for Jimai 22 (JM22), Jingdong 18 (JD18) and Yangmai 18 (YM18), respectively; whereas at 100 mg L–1 AGP level, CS (105.44%), Chuannong 16 (CN16) (80.60%) and Ningchun 4 (NC4) (62.87%) acted the best. Moreover CS (79.05%), JM22 (7.55%), CN16 (101.87%), YM18 (365.56%), Yangmai 20 (YM20) (10.48%), and CB301 (187.40%) were more responsive to 0.005 ‰ of H2O2, and NC4 (35.37%) obtained the highest shoot regeneration rates at 0.01 ‰ of H2O2. Overall, these two methods, inter-culture and AGP (or H2O2) application, can be further applied to wheat transgenic research.

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°C 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°C for spring wheat type cv. CB037 and approximately 300°C for winter wheat type cv. Kenong 199. Regeneration ability obviously declined when the highest environmental temperature was over 35°C for 1 d or a high temperature between 30 and 33°C 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°C in different controlled growth incubators for 5 d; the IEs almost completely lost regeneration ability when the temperature rose to 37°C. Cryopreservation of -20°C caused the wheat samples lost ability of producing callus or embryonic callus in a few days, and cryopreservation of -10°C more than 10 d made the regeneration potential of the tissues dramatically declined. Comparatively, the temperature that best maintained high regeneration ability was -5°C, at which the materials can be maintained for around 1 mon. In addition, the preservation of the immature samples at -5 or -10°C 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.

Normalized Difference Vegetation Index (NDVI) is a very useful feature for differentiating vegetation and non-vegetationin remote sensed imagery. In the light of the function of NDVI and the spatial patterns of the vegetation landscapes, weproposed the lacunarity texture derived from NDVI to characterize the spatial patterns of vegetation landscapes concerningthe “gappiness” or “emptiness” characteristics. The NDVI-based lacunarity texture was incorporated into object-orientedclassification for improving the identification of vegetation categories, especially Torreya which was the targeted treespecies in the present research. A three-level hierarchical network of image objects was defined and the proposed texturewas integrated as potential sources of information in the rules base. A knowledge base of rules created by classifierC5.0 indicated that the texture could potentially be applied in object-oriented classification. It was found that the additionof such texture improved the identification of every vegetation category. The results demonstrated that the texture couldcharacterize the spatial patterns of vegetation structures, which could be a promising approach for vegetation identification.