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Ammonium (NH4+) is a major nitrogen source for tea plant growth. Although NH4+-induced growth of tea plants were reported, it was still unclear to elucidate the mechanism of proteins in tea plants in responding to NH4+ resupply. In the present study, the proteomic profiles of tea leaves under N deficiency/resupply were investigated by using LC-MS/MS and PRM technique. Compared with N deficiency, there were 247 and 328 proteins significantly expressed after 3 h and 3d of N resupplied, respectively. And compared with 3 h of N resupplied, there were 186 proteins significantly expressed after 3d of N resupplied. According to bioinformatics analysis, the results showed that different expressed proteins participated in various biological processes, such as PsbO, Pbs27, PsaN, and PsaF were involved in photosynthesis, ADH1, AOC3, URE, GDH1-2, and argD were involved in amino acid metabolism, CHI and ANR were involved in flavonoid biosynthesis, GSTF9, APX, and GSS were involved in glutathione metabolism, and PdxT and PdxS were involved in vitamin B6 metabolism. Through PPI analysis, the results showed that the interactions between different expressed proteins mainly occurred in the photosynthetic pathway. Ammonium supply has a profound impact on photosynthesis, amino acid metabolism, flavonoid biosynthesis, glutathione metabolism, and vitamin B6 metabolism. [ABSTRACT FROM AUTHOR]

Intercropping two species at different growth stages is common in temperate and tropical areas. An apparent recovery of growth is observed in late-maturing species after early-maturing species have been harvested, but the mechanism remained unclear. This study tested the hypothesis that the roots of late-maturing species occupy greater below-ground space at later growth stages. The monolith method was employed to investigate the spatial and temporal distribution of maize grown alone (no interspecific interactions), maize intercropped with wheat (asymmetric interspecific facilitation before wheat harvesting), and maize intercropped with faba bean (symmetric interspecific facilitation) on August 8, September 2 and September 30, after harvesting of wheat (July 15) or faba bean (August 2). The results show that maize intercropped with wheat occupied more below-ground space at late growth stages than at early growth stages when the two crops grew at the same time, thus supporting our hypothesis. Furthermore, we also found that interspecific interactions during the co-growth stage of the two species led to a longer root life span in both maize intercropped with wheat and faba bean compared to the maize grown alone. The findings may partly explain the recovery of late-maturing species found in intercropping systems between two crop species with different growth stages and the complementary effect on the relationship between plant biodiversity and productivity. [ABSTRACT FROM PUBLISHER]

One-third of all the cultivated land area is used for multiple cropping and half of the total grain yield is produced with multiple cropping in China. There have been numerous studies on nutrient acquisition by crops in legume/non-legume intercropping systems, but few on nutrient uptake in cereal/cereal intercropping. This paper describes a field experiment in which integrated wheat/maize and maize/faba bean systems were compared with sole wheat and sole faba bean cropping to assess the effects of intercropping on nutrient uptake by wheat, maize, and faba bean under various application rates of nitrogen (N) and phosphorous (P) fertilizers. Results show that both N and P fertilizers and intercropping enhanced N uptake by wheat, while only P fertilizer and intercropping increased P acquisition by wheat. The advantage of N uptake by border rows of wheat intercropped with maize declined with increasing N fertilizer application rate, but that of P acquisition was not affected by P fertilizer. The amounts of both N and P taken up by maize intercropped with faba bean were much higher than those by maize intercropped with wheat throughout the period of intercropping. Both fertilization and intercropping did not influence the N and P uptake by faba bean. [ABSTRACT FROM AUTHOR]