通过2年定位试验研究不同玉米-豆科间套作模式下（玉米-大豆带状套作、玉米-花生带状间作、玉米净作、大豆净作和花生净作）作物氮素吸收与根系分布、豆科结瘤和土壤氮素有效性之间的关系。结果表明：与净作相比，间套作显著降低了单季作物的单位面积吸氮量，但玉米-大豆套作和玉米-花生间作的系统总吸氮量分别增加31.7-45.4%和7.4-12.2%。间套作显著增加了玉米和大豆的单株氮素吸收量，与净作相比分别增加61.6%和31.8%，间作花生的单株吸氮量较净作降低46.6%。间套作系统中玉米和大豆的根系呈现不对称性分布，其根长密度和根表面密度显著高于相应单作。间作花生受竞争抑制，其根表面密度显著低于相应单作。与净作相比，套作大豆的根瘤数量和根瘤鲜重显著增加，间作花生根瘤数和根瘤鲜重则显著降低。间套作显著提高了玉米和大豆的土壤酶活性（蛋白酶、脲酶、硝酸还原酶）和土壤有效氮含量，但降低了花生的土壤酶和土壤有效氮含量。玉米-大豆带状套作系统比玉米-花生带状间作系统更有利于氮素吸收，玉米与豆科间套作可以促进玉米对氮素的吸收，从而降低氮肥用量，提高农业可持续性。

JAZ（The jasmonate ZIM domain）蛋白属于TIFY(TIF[F/Y]XG)家族，它是由植物特异性蛋白组成，在植物生长发育和防御反应中具有十分重要的作用。然而，对于高粱JAZ家族基因在植物响应非生物胁迫的机制尚不清楚。本研究采用隐马尔可夫模型，在高粱中共鉴定到17个JAZ基因。此外，采用实时荧光定量PCR (RT-qPCR) 对高粱JAZ基因在非生物胁迫下的表达模式进行分析。系统发育分析表明，高粱JAZ蛋白主要分为9个亚家族，其启动子区包含多种类型的启动子顺式作用元件，表明JAZ蛋白在植物的胁迫响应中起作用。RT-qPCR结果显示，SbJAZ家族基因的表达具有组织特异性，在冷、热、聚乙二醇、茉莉酸、脱落酸和赤霉素处理下，SbJAZ基因的表达出现明显差异，表明SbJAZ基因参与植物对不同胁迫的响应。此外，在大肠杆菌中表达SbJAZ1可促进重组细胞在非生物胁迫（PEG 6000、NaCl 和 40°C）下的生长。综上所述，本研究结果将有助于更好地了解高粱SbJAZ家族响应非生物胁迫的潜在分子机制。

尽管目前的研究极大地促进了我们对于植物适应低氮胁迫的认知，但是关于不同作物基因型适应低氮胁迫能力不同的机制仍需要进一步探讨。本文中，我们根据田间条件下304份玉米自交系对低氮胁迫的耐受性，从中选择了Ye478（低氮胁迫敏感材料）和Qi319（耐受低氮胁迫材料）进行进一步的研究。首先我们对Ye478和Qi319正常氮水培和低氮水培的地上部和根部构建了16个转录组文库，并进行高通量测序。结果分析发现Qi319根系中特异上调表达的基因主要富集在代谢能相关途径，包括三羧酸代谢过程和烟酰胺代谢过程。在低氮胁迫处理5天后，仅在Ye478中观察到老叶变黄的表型；与Qi319相比，在Ye478地上部特异下调表达的基因主要与类囊体、叶绿体、光合膜和叶绿体基质等有关。对转录因子进行分析，共有216个转录因子在Ye478和Qi319之间差异表达，表明氮胁迫响应路径中的转录调控在不同作物基因型适应低氮胁迫中起重要作用。此外，在Ye478和Qi319中还发现了15个差异表达的miRNAs。综上所述，我们的研究有助于了解玉米耐受低氮胁迫的遗传变异和分子基础。

In China, the abuse of chemical nitrogen (N) fertilizer results in decreasing N use efficiency (NUE), wasting resources and causing serious environmental problems.  Cereal-legume intercropping is widely used to enhance crop yield and improve resource use efficiency, especially in Southwest China.  To optimize N utilization and increase grain yield, we conducted a two-year field experiment with single-factor randomized block designs of a maize-soybean intercropping system (IMS).  Three N rates, NN (no nitrogen application), LN (lower N application: 270 kg N ha^–1), and CN (conventional N application: 330 kg N ha^–1), and three topdressing distances of LN (LND), e.g., 15 cm (LND1), 30 cm (LND2) and 45 cm (LND3) from maize rows were evaluated.  At the beginning seed stage (R5), the leghemoglobin content and nitrogenase activity of LND3 were 1.86 mg plant^–1 and 0.14 mL h^–1 plant^–1, and those of LND1 and LND2 were increased by 31.4 and 24.5%, 6.4 and 32.9% compared with LND3, respectively.  The ureide content and N accumulation of soybean organs in LND1 and LND2 were higher than those of LND3.  The N uptake, NUE and N agronomy efficiency (NAE) of IMS under CN were 308.3 kg ha^–1, 28.5%, and 5.7 kg grain kg^–1 N, respectively; however, those of LN were significantly increased by 12.4, 72.5, and 51.6% compared with CN, respectively.  The total yield in LND1 and LND2 was increased by 12.3 and 8.3% compared with CN, respectively.  Those results suggested that LN with distances of 15–30 cm from the topdressing strip to the maize row was optimal in maize-soybean intercropping.  Lower N input with an optimized fertilization location for IMS increased N fixation and N use efficiency without decreasing grain yield.

Potassium (K) deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world. However, the physiological mechanism of K deficiency tolerance is not yet fully understood. To identify the differences of root morphology, physiology and endogenous hormones at different growing stages, two maize inbred lines 90-21-3 (tolerance to K deficiency) and D937 (sensitive to K deficiency) were cultivated in the long-term K fertilizer experimental pool under high potassium (+K) and low potassium (–K) treatments. The results indicated that the root length, volume and surface area of 90-21-3 were significantly higher than those of D937 under –K treatment at different growing stages. It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under –K treatment. Meanwhile, the values of superoxide dismutase (SOD) and oxidizing force of 90-21-3 were apparently higher than those of D937, whereas malondialdehyde (MDA) content of D937 was obviously increased. Compared with +K treatment, the indole-3-acetic acid (IAA) content of 90-21-3 was largely increased under –K treatment, whereas it was sharply decreased in D937. On the contrary, abscisic acid (ABA) content of 90-21-3 was slightly increased, but that of D937 was significantly increased. The zeatin riboside (ZR) content of 90-21-3 was significantly decreased, while that of D937 was relatively increased. These results indicated that the endogenous hormones were stimulated in 90-21-3 to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.