Lycium barbarum residue (LBR), a by-product of L. barbarum processing, is packed with bioactive components and can be potentially utilized as a feed additive in animal husbandry.  However, the fundamental understanding of its effectiveness on livestock animals is still lacking, particularly in ruminants.  To explore the effects of LBR on the growth performance, rumen fermentation parameters, ruminal microbes and metabolites of Tan sheep, sixteen fattening rams (aged 4 mon) were fed a basal diet (CON, n=8) or a basal diet supplemented with 5% LBR (LBR, n=8).  The experiment lasted for 70 d, with 10 d adaptation period and 60 d treatment period.  The results showed that the LBR enhanced the average daily feed intake, average daily gain (P<0.05), and ruminal total volatile fatty acids (P<0.01) while decreasing ammonia-nitrogen concentration and rumen pH value (P<0.05).  Additionally, the LBR improved the relative abundances of Prevotella, Succiniclasticum, Ruminococcus, Coprococcus, Selenomonas, and Butyrivibrio (P<0.05) and reduced the relative abundances of Oscillospira and Succinivibrio (P<0.05).  The LBR altered the ruminal metabolome (P<0.01) by increasing the abundances of ruminal metabolites involved in amino acids (e.g., L-proline, L-phenylalanine, L-lysine, and L-tyrosine), pyrimidine metabolism (e.g., uridine, uracil, and thymidine), and microbial protein synthesis (e.g., xanthine and hypoxanthine).  In conclusion, LBR had positive effects on the growth rate of Tan sheep as well as on rumen fermentation parameters, rumen microbiome and rumen metabolome.

Aligning leaf nitrogen (N) distribution to match the light gradient is crucial for maximizing canopy dry matter production (DMP) and improving N utilization efficiency.  However, the relationship between the gradient of root-derived cytokinins and N distribution in rice leaves, along with its impact on DMP and the underlying mechanisms, remains poorly understood.  A two-year field experiment was conducted using two japonica N-efficient varieties (NEVs) and two japonica N-inefficient varieties (NIVs) under four different N rates (0, 90, 180 and 360 kg N ha⁻¹). These selected varieties exhibited similar values in the coefficient of light extinction (K_L).  Results showed that, at lower N rates (0-180 kg N ha⁻¹), the NEVs exhibited greater dry matter weight at maturity, higher grain yield and improved internal N use efficiency (IE_N), compared to the NIVs, despite possessing comparable total N uptake.  Compared with the NIVs, the NEVs exhibited a more pronounced nitrogen distribution gradient in leaves, as indicated by the coefficient of nitrogen extinction (K_N) values during the middle and early grain filling stages.  This enhanced gradient led to improved coordination between light and nitrogen, resulting in greater photosynthetic production, particularly at lower N rates. Furthermore, the NEVs demonstrated a larger gradient of zeatin (Z)+zeatin riboside (ZR) in leaves (i.e., higher ratios of Z+ZR levels between upper and lower leaves), enhanced expression levels of genes related to N export in lower leaves and Z+ZR loading in root, respectively, elevated enzymes activities related to N assimilation in upper leaves, in relative to the NIVs.  Correlation and random forest analyses demonstrated a strong positive correlation between Z+ZR gradient, K_N, and DMP, and the gradient facilitated the export of N from lower leaves and its assimilation in upper leaves, contributing significantly to both K_N and DMP.  This process was closely linked to root activity, including root oxidation activity, root Z+ZR content, and Z+ZR loading capacity, as confirmed by applying an inhibitor or a promoter of cytokinins biosynthesis to roots.  Interestingly, at the N rate of 360 kg N ha⁻¹, both NEVs and NIVs showed indistinguishable plant traits, achieving a super high-yielding level (over 10.5 t ha⁻¹) but with remarkably low IE_N.  The results suggest that increasing Z+ZR gradient can improve K_N and DMP, where it needs to maintain higher root activity, thus leading to high yield and high IE_N.  Further research is needed to explore and develop cultivation practices with reduced N to unlock the super high-yielding potential of the NEVs.

Lodging is a primary factor limiting rice grain yield. How to achieve the synergistic improvement of high yield and nitrogen use efficiency without lodging has always been the focus worldwide.  In this study, Yongyou 2640 (indica-japonica hybrid rice) and Jinxiangyu 1 (inbred japonica rice) were used as materials for field experiments across two years. Six different nitrogen managements were set up, including no nitrogen (T1), conventional urea (T2), controlled-release nitrogen (T3), reduction of controlled-release nitrogen (T4), controlled-release nitrogen combined with one-time basal conventional urea (T5), controlled-release nitrogen combined with split conventional urea (T6).  The results showed that compared with T2, the combined application strategy of controlled-release nitrogen (T5 and T6) could improve nitrogen use efficiency and grain yield by 4.89–5.69% and 3.41–4.65%, respectively.  The carbohydrate contents of the second basal internode, the internode breaking strength, the thickness of the epidermal silicon layer, the number of large and small vascular bundles, and the thickness of parenchymatous tissue and mechanical tissue were increased, whereas the internode length, bending moment and lodging index were reduced under the combined application strategy of controlled-release nitrogen.  These results indicated that the combined application strategy of controlled-release nitrogen could achieve the goal of high yield and nitrogen use efficiency with synchronously increased stem strength due to the improvement in the morphological, mechanical, physicochemical and anatomical properties of second basal stem.

This study examined the involvement of cytokinins in the process by which moderate water limitation (MWL) mediates nitrogen (N) remobilization from source to sink during the grain-filling phase in wheat.  Field experiments were performed using N application rates of low (LN), medium (MN), and high (HN).  Two soil moisture regimes were implemented for each N rate: conventional well-watered (CWW) and MWL post anthesis. The MWL application optimized N, total free amino acids (FAA), trans-zeatin (Z)+trans-zeatin riboside (ZR) reallocation from the source organs (stems and leaves) to the sink organ (spikes) in wheat.  Compared to those in the CWW regime, the activities of proteolytic enzymes, including endopeptidase, carboxypeptidase and aminopeptidase within stems and leaves, and the expression levels of total FAA transporter genes in spikes were significantly elevated in the MWL regime, showing a close correlation with the Z+ZR levels in the spikes.  Application of kinetin to stems and leaves significantly inhibited proteolytic enzyme activity, promoting N retention in stems and leaves, decreasing N accumulation in the sink organ, and reducing the N harvest index.  In contrast, the applying kinetin to spikes significantly upregulated expression levels of FAA transporter genes, reducing N retention in stems and leaves, increasing N accumulation in the sink organ, and raising the N harvest index.  Such facilitation induced by the MWL in remobilization of N from source to sink was greater at HN than at LN or MN.  Results demonstrate that post-anthesis MWL can significantly intensify the remobilization of N from source to sink, while also synergistically enhancing grain yield and N use efficiency through strategically redistributing cytokinins (Z+ZR) between source and sink in wheat.