谷类/豆类间作已在世界范围内被广泛采用，以提高可持续农业系统中的作物生产力。在不同的间作组合中，谷子/花生间作可以适应大部分缺水地区。然而，关于谷子/花生间作与单作在不同施氮水平下的产量性状和氮素利用效率差异的研究较少。本研究旨在确定谷子/花生间作的产量优势、经济效益以及适宜的氮肥用量。采用三种种植模式（单作谷子、单作花生和谷子/花生间作）和四种施氮量（0、75、150和225 kg ha^-1）进行了为期两年的大田试验。结果表明，间作系统的土地当量比（LER）和净效应（NE）在施氮量为150 kg ha^-1时达到两年来的最高值（LER两年平均为1.04，NE分别为0.347 Mg ha^-1）。谷子是间作系统中的优势作物（谷子与花生的种间相对竞争能力（Amp）>0，竞争比率（CRmp）>1），单作在施氮量为225 kg ha^-1，间作为150 kg ha^-1时谷子产量最高。不同种植模式的氮利用效率（NUE）两年均在施氮量为150 kg ha^-1时达到最高。间作结合施氮150 kg ha^-1时净收益最高，两年平均为2791 $ ha^-1，效益成本比为1.56。因此，从经济和农业可持续发展的角度来看，150 kg N ha^-1施氮量的谷子/花生间作似乎是替代谷子或花生单作的一个有推广价值的选择。

本研究以花育25为材料，设置非盐胁迫(CK)，0.15％(S1)和0.3％盐胁迫(S2)三个处理，探究了盐胁迫对花生光合特性、植株不同器官干物质积累与分配及荚果发育动态的影响。结果表明，盐胁迫降低了花生的净光合速率(P_n)，SPAD值，单株叶面积和产量；播种后第50天，CK的P_n分别较S1和S2处理高出13.71％和28.72％。同一生育期内，处理间的SPAD值差异均为CK>S1>S2。盐胁迫降低了花生的单株荚果重，百果重，百仁重和出米率，大小为CK>S1>S2。与CK相较，花生通过改变了光合产物在不同器官中的分配比例来适应盐胁迫，在营养生长和早期生殖期生长阶段，S1和S2处理增加了光合产物在茎和荚果中分配比例。整个生育期内，S1和S2处理的根系干重集中分布在0-40厘米的土壤层中。荚果发育过程中，S1和S2处理的荚果体积、干重和果仁干重的最大生长速率(V_max)均下降；收获时，S1和S2处理的荚果和果仁的体积较CK均降低，因此盐胁迫下花生通过降低荚果和果仁体积来提高饱满度。以上发现为盐碱地种植花生提供了理论指导。

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.

Potassium is an important nutrient element requiring high concentration for photosynthetic metabolism. The potassium deficiency in soil could inhibit soybean (Glycine max (L.) Merr.) photosynthesis and result in yield reduction. Research on the photosynthetic variations of the different tolerant soyben varieties should provide important information for high yield tolerant soybean breeding program. Two representative soybean varieties Tiefeng 40 (tolerance to K+ deficiency) and GD8521 (sensitive to K+ deficiency) were hydroponically grown to measure the photosynthesis, chlorophyll fluorescence parameters and Rubisco activity under different potassium conditions. With the K-deficiency stress time extending, the net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of GD8521 were significantly decreased under K-deficiency condition, whereas the intercellular CO2 concentration (Ci) was significantly increased. As a contrast, the variations of Tiefeng 40 were almost little under K-deficiency condition, which indicated tolerance to K+ deficiency variety could maintain higher efficient photosynthesis. On the 25th d after treatment, the minimal fluorescence (F0) of GD8521 was significantly increased and the maximal fluorescence (Fm), the maximum quantum efficiency of PSII photochemistry (Fv/ Fm), actual photochemical efficiency of PSII (ΦPSII), photochemical quenching (qP), and electron transport rate of PSII (ETR) were significantly decreased under K+ deficiency condition. In addition, the Rubisco content of GD8521 was significantly decreased in leaves. It is particularly noteworthy that the chlorophyll fluorescence parameters and Rubisco content of Tiefeng 40 were unaffected under K+ deficiency condition. On the other hand, the non-photochemical quenching (qN) of Tiefeng 40 was significantly increased. The dry matter weight of Tiefeng 40 was little affected under K+ deficiency condition. Results indicated that Tiefeng 40 could avoid or relieve the destruction of PSII caused by exceeded absorbed solar energy under K-deficiency condition and maintain natural photosynthesis and plant growth. It was an essential physiological mechanism for low-K-tolerant soybean under K-deficiency stress.