Rice grown under anaerobic waterlogged soil condition takes up ammonium as a major source of nitrogen (N). A substantial quantity of nitrate is taken up by rice when aeration conditions prevail. This work compared the physiological and molecular responses of N-depleted rice (Oryza sativa L. japonica ssp. cv. Wuyunjing) to re-supply of different N sources in a hydroponic system. Expression of six genes known to be related to N uptake and assimilation in roots was analyzed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). N starvation increased root growth but decreased shoot biomass and nitrate reductase (NR) activity. In comparison to nitrate as N source, ammonium tended to inhibit root growth but significantly improved shoot growth, total N uptake, and, particularly, the translocation of N to the above ground parts. Replacing half of the ammonium by nitrate in the single ammonium solution increased glutamine synthetase (GS) activity and total N uptake. This replacement enhanced expression of OsAMT1;3 but decreased the expression of OsAMT1;2 in the roots. Likewise, replacing half of the nitrate by ammonium in the single nitrate solution, increased NR activity and expression of an NR gene (OsNR1) but suppressed expression of OsNRT2 in the roots. Expression of both OsAMT1;1 and a GS gene (OsGS1;1) was relatively constant and not affected by the N form or starvation in the rice roots. Predominant beneficial effects of dual supply of the two forms of N in comparison with a single form of N either as ammonium or as nitrate might be due to improvement of ammonium uptake due to nitrate presence near the roots and enhanced reduction of nitrate in leaves by ammonium.

Here, orthologous genes of six phosphate transporter (PiT) genes, which are members of the Pht1 and Pht2 families in tomato and potato, have been cloned from the solanaceous species pepper, eggplant and tobacco. Overall, expressions of these genes in pepper, eggplant and tobacco showed similar patterns to those in tomato and potato: P-starvation enhancement in both leaves and roots for Pht1; 1, P-depletion induction exclusively in roots for Pht1; 2, mycorrhizal enhancement for Pht1; 3, and mycorrhizal induction for both Pht1; 4 and Pht1; 5. In the roots of nonmycorrhizal eggplant, SmPht1; 3, SmPht1; 4 and SmPht1; 5 were also expressed under extreme P starvation. Mycorrhizal symbiosis under high-P supply conditions reduced plant growth, with concurrent enhancement of Pht1; 2 expression in the roots of pepper as well as eggplant. In addition, the mycorrhizal symbiosis down-regulated the expression of Pht2; 1 genes greatly in the leaves of pepper and tobacco. The discrepancies between the evolutionary distances of the PiT genes and their expression patterns among the five species suggest greater complexity in function of PiT in plants than previously expected.

采用实时荧光定量PCR技术，通过使用特异引物，对水稻中的低丰度表达基因Osamt1；3进行了转录水平上的定量分析，成功建立了可检测低丰度表达基因的SYBRGreen实时荧光定量PCR技术平台。该方法具有很好的准确性和实用性。获得的荧光定量PCR扩增曲线，基线平整，指数区明显，斜率大且固定；线性范围广，17～36个循环都能测出；稳定性、重复性好，变异系数仅为0.47%；标准曲线表明，循环闽值与PCR体系中起始模板量的对数值之间有着良好的线性关系，可对基因表达进行相对定量；缺氯条件下OSAMTI；3与纯NH4+处理相比表达量增加4倍以上。

文章初步建立了地被菊品种‘早小春’组织培养植株再生系统和农杆菌介导的稳定转化系统。幼蕾管状花瓣诱导培养获得再生植株的最适培养基为MS+2.0mg•L-1ZT+0.5mg•L-12，4-D，愈伤组织诱导率可达95%以上，不定芽的分化率达到87%以上。以再生植株叶片为外植体进行遗传转化实验的结果表明：用MS液体培养基稀释的农杆菌液效果最佳，以感染8min左右，共培养3d为宜。同时附加40mg•L-1卡那霉素和500mg•L-1头孢霉素是地被菊转化的最佳条件。

为了更好地研究植物在磷素吸收过程中的分子机制以及生物化学过程的变化，将水稻中分离得到的一个磷转运蛋白基因（OsPT6）用于互补实验。互补实验结果表明，OsPT6能够与缺失磷转运功能的酵母突变体实现互补，并在低磷条件下促进酵母突变体对磷的吸收。进一步分析表明OsPT6属于水稻Phtl家族运输蛋白基因，所编码的蛋白对磷酸盐（Pi）的吸收Km值为96μmol/L，属于高亲和的磷转运蛋白。不同的酵母转化子对不同pH环境的响应实验显示，OsPT6是一个与质子相偶联的磷运输蛋白，其吸收磷素的最佳pH为6.0。对OsPT6在人的胚胎肾细胞（HEK293）中的表达分析表明，该基因能够编码蛋白并定位于细胞膜，证明OsPT6的功能与酵母磷转运子PHO84相似，是一个定位于细胞膜上的具有吸收转运磷素作用的运输蛋白。

通过PCR从粳稻（OryzaSalicvaL.cv.ssp.Japonica）的总DNA中扩增出一个磷转运蛋白基因（Phosphalestransporter1；6；Osphl1；6，accessionnoAF563666）的启动子序列以此为基础与二元表达载体PslaG3构建含Phl1；6启动子的植物表达载体，并通过根癌农杆菌介导转化了水稻武运粳7号品种同时，对其愈伤组织高效再生体系和影响报告基因GUS瞬时表达的各种因素也做了比较研究结果表明：①诱导水稻武运粳7号品种愈伤形成，3mg/L2，4D的生长素浓度最适宜；②GUS基因高瞬时表达频率的条件为：工程菌液的浓度OD600值为0.70.8，浸染时间30min，共培养时间3d。利用这些再生转化条件，以EHAl05为菌株转化浸染愈伤组织，获得了较高频率的Pht1；6启动子驱动的GUs基因瞬时表达这些方法都有效地提高了抗性愈伤组织的形成率，该实验获得了转基因植株，经PCR检测，证实已将目的基因整合到水稻的基因组中。

丛枝菌根（arbuscularmycorrhizal，AM）共生是丛枝菌根真菌与大多数陆地植物的根系之间形成的一种互利共生关系。植物给菌根真菌提供碳水化合物；作为回报，菌根真菌能够增强植物对矿质营养元素（尤其是磷）的吸收。菌根的形成过程是一系列信号交换和转导的结果，具有严格并且一致的顺序。本文以植物中菌根形成的信号途径为主线，对菌根真菌的形成过程和信号转导途径及其方式进行了分析和讨论。高等植物中菌根形成的信号途径与豆科植物的结瘤信号途径部分共享，并且与钙离子信号途径相关，但前者更为广泛。尽管该途径中很多过程目前还不十分清楚，但是相信在不久的将来就可以揭开菌根形成过程中的众多谜团。

利用控制条件下的溶液培养方法，研究了增硝营养（NH4+：N03-比例为100：0和50：50）对两种不同的基因型水稻南光和云粳苗期生长和硝酸还原酶（NR）活性及基因表达量的影响。结果表明，不同基因型水稻在增NO3-营养下生物量、氮素含量、氮积累量的增幅南光大于云粳。NO3-的存在增强了水稻硝酸还原酶的活力和NR基因OsNial、DsMn2的表达。不同基因在水稻幼苗中，两个品种OsNia2的相对表达量均高于OsNial。就品种而言，无论叶片还是根系，增硝后南光OsNia2mRNA表达量都高于云粳；南光叶片OsNialmRNA表达量也较云粳叶片高。增硝营养提高了水稻NR基因的表达，增加了NR活性，促进了水稻NO3-的同化利用，从而增加了氮素在植株地上部的积累同化。南光和云粳相比，前者对NO3-的响应更为强烈。