细胞死亡是多细胞生物生命中一种重要的生理现象。当呼吸和新陈代谢等正常功能停止时，将会发生细胞死亡。细胞死亡可分为程序性细胞死亡和非程序性细胞死亡。正常组织中发生的程序性细胞死亡，通常是维持组织机能和形态所必须的。非程序性细胞死亡则通常由非生物或生物胁迫引起。近年来，大量研究报道植物在抵御病原菌时出现了细胞死亡现象。通过分析调控植物免疫反应和细胞死亡的蛋白（PICD），发现PICD主要参与丝裂原活化蛋白激酶（MAPK）级联、活性氧（ROS）、植物激素、泛素-蛋白酶体系统、Ca²⁺信号、物质转运等六种主要的反应过程，且这些反应过程存在内在的联系。同时，PICD主要分为八类，如：含有核苷酸结合结构域和富含亮氨酸重复序列的蛋白（NLR）蛋白、受体或类受体激酶、E3泛素连接酶和其相关蛋白、ATP和GTP相关蛋白、转录因子、14-3-3蛋白和其相关蛋白、类eEF1A蛋白和丝氨酸蛋白酶抑制子，部分PICD类型具有单、双子叶植物特异性。植物细胞死亡不仅与病原相关分子模式激发的免疫反应（PTI）、效应因子激发的免疫反应（ETI）紧密相关，也与系统获得性抗性（SAR）存在重要关联。PICD在细胞外基质、细胞膜、细胞质、细胞核、线粒体、叶绿体、内质网膜、多囊泡体等众多细胞结构中均有分布，表明细胞在应对病原菌侵染和调控自身死亡时存在精妙地协同调控作用。此外，植物在抵御病原菌时的细胞死亡，通常对其自身的生长发育不利。通过筛选优异的等位变异和基因编辑等技术手段，期望达到植物免疫和生长发育间的平衡，以此增强PICD在植物应用领域中的潜力。

Soil management practices affect rhizosphere microorganisms and enzyme activities, which in turn influence soil ecosystem processes. The objective of this study was to explore the effects of different nitrogen application rates on wheat (Triticum aestivum L.) rhizosphere soil microorganisms and enzyme activities, and their temporal variations in relation to soil fertility under supplemental irrigation conditions in a fluvo-aquic region. For this, we established a split-plot experiment for two consecutive years (2014–2015 and 2015–2016) in the field with three levels of soil moisture: water deficit to no irrigation (W1), medium irrigation to (70±5)% of soil relative moisture after jointing stage (W2), and adequate irrigation to (80±5)% of soil relative moisture after jointing stage (W3); and three levels of nitrogen: 0 kg ha^–1 (N1), 195 kg ha^–1 (N2) and
270 kg ha^–1 (N3).  Results showed that irrigation and nitrogen application significantly increased rhizosphere microorganisms and enzyme activities.  Soil microbiological properties showed different trends in response to N level; the highest values of bacteria, protease, catalase and phosphatase appeared in N2, while the highest levels of actinobacteria, fungi and urease were observed in N3.  In addition, these items performed best under medium irrigation (W2) relative to W1 and W3; particularly the maximum microorganism (bacteria, actinobacteria and fungi) amounts appeared at W2, 5.37×10⁷ and 6.35×10⁷ CFUs g^–1 higher than those at W3 in 2014–2015 and 2015–2016, respectively; and these changes were similar in both growing seasons.  Microbe-related parameters fluctuated over time but their seasonality did not hamper the irrigation and fertilization-induced effects.  Further, the highest grain yields of 13 309.2 and 12 885.7 kg ha^–1 were both obtained at W2N2 in 2014–2015 and 2015–2016, respectively.  The selected properties, soil microorganisms and enzymes, were significantly correlated with wheat yield and proved to be valuable indicators of soil quality.  These results clearly demonstrated that the combined treatment (W2N2) significantly improved soil microbiological properties, soil fertility and wheat yield on the Huanghuai Plain, China.

Photoperiodic response is an important characteristic that plays an important role in plant adaptability for various environments. Wheat cultivars grow widely and have high yield potential for the strong photoperiod adaptibility. To assess the photoperiodic response of different genotypes in wheat cultivars, the photoperiodic effects of the Ppd-D1 alleles and the expressions of the related TaGI, TaCO and TaFT genes in Liaochun 10 and Ningchun 36 were investigated under the short-day (6 h light, SD), moderate-day (12 h light, MD) and long-day (24 h light, LD) conditions. Amplicon length comparison indicated that the promoter of Ppd-D1 in Ningchun 36 is intact, while Liaochun 10 presented the partial sequence deletion of Ppd-D1 promoter. The durations of all developmental stages of the two cultivars were reduced by subjection to an extended photoperiod, except for the stamen and pistil differentiation stage in the Liaochun 10 cultivar. The expression levels of the Ppd-D1 alleles and the TaGI, TaCO and TaFT genes associated with the photoperiod pathway were examined over a 24-h period under SD and MD conditions. The relationships of different photoperiodic responses of the two cultivars and the expression of photoperiod pathway genes were analyzed accordingly. The photoperiod insensitive (PI) genotype plants flower early under SD; meanwhile, the abnormal expression of the Ppd-D1a allele is accompanied with an increase in TaFT1 expression and the TaCO expression variation. The results would facilitate molecular breeding in wheat.

The homeobox transcription factor WUSCHEL (WUS) plays a critical role in keeping the balance between the maintenance and differentiation of stem cell population in shoot and floral meristems of Arabidopsis thaliana. The corresponding gene SlWUS is yet to be characterized in tomato. In order to characterize SlWUS gene and its biological function, we cloned it from tomato and analyzed its structure. Tissue expression showed that the SlWUS highly expressed in tomato flower abscission zone. The overexpression of SlWUS in Arabidopsis could trigger undifferentiation of plant flower organ and indeterminacy of flower identity, suggesting that SlWUS maybe involved in flower structure development as well as flower organ identity. Taken together, our results indicated that the SlWUS plays an important role in flower abscission zone and plant organ shedding.

The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions obtained from different cultivars and different parts of new shoots were varied. There were many chemical components participating in the formation of green tea cream. However, there were only the contents of caffeine (Y=0.85, P<0.01) and polyphenols (Y=0.65,P<0.05) in the original green tea infusion highly correlated with the amount of green tea cream. Stepwise regression analysis of overall chemical components indicated that the contents of caffeine and gallated catechins in the original green tea infusion had a significant effect (P<0.01) on green tea cream levels. Cream (g L^-1)=-172.071+ 0.129 x C_caffeine+0.024xG_{gallated catechins} (R²=0.936). The amount of green tea cream can be predicted by the contents of gallated catechins and caffeine in the original tea infusion. Principal component analysis also indicated that catechins, minerals, and polysaccharides were the important chemical components in the formation of green tea cream.