Low ambient temperature is not conducive to hydration of cement material, resulting in low strength for cemented paste backfill (CPB). Therefore, the aim of this study is to investigate the effect of early-strength agent (ESA) on mechanical strength and hydration exothermic behaviour of CPB under low temperature. Influence factors including the ESA types, superposing patterns and dosages were evaluated on CPB by conducting unconfined compressive strength (UCS), hydration exothermic tests and thermogravimetric analysis. The obtained results show that with exception of sodium chloride (NaCl), the single ESAs of sodium sulphate (Na₂SO₄), calcium chloride (CaCl₂), lithium bromide (LiBr) and triisopropanolamine (TIPA) exert positive effect on UCS of CPB. The optimal dosages of Na₂SO₄, CaCl₂, LiBr and TIPA are 2.0-, 1.0-, 0.3- and 0.08- wt.%. By means of superimposing optimisation, the binary ESA that consists of 0.08 wt.% TIPA and 2.0 wt.% Na₂SO₄ is obtained. Adding different ESAs at optimum dosages can facilitate hydration reaction of cement. Both hydration exothermic rate, cumulative heat release and internal temperature increase, thereby more amount of hydration products form inside CPB. This contributes CPB to obtain higher initial temperature and UCS under low temperature.

Rice yield is closely related to plant leaf shape and chlorophyll content. In this study, we isolated and identified a narrow and rolled leaf mutant, temporarily named nrl3 with darker green leaves. Histological analysis showed that nrl3 has a reduced number of vascular bundles and undergoes abnormal abaxial sclerenchymatous cell differentiation. The NRL3 mutant phenotype was controlled by a single recessive gene, fine-mapped to a 221 kb interval between Indel3 and RM2322 on Chr3. There are 42 ORF in this interval. Sequencing identified an SNP mutant leading to a premature stop in ORF 18, the candidate gene. Bioinformation analysis indicated that NRL3 encodes a novel protein with unknown function. NRL3 is localized in cytoplasm, membrane and nucleus. Expression analysis of nrl3 showed that genes involved in chlorophyll synthesis were significantly up-regulated while those involved in chlorophyll degradation and programmed cell death (PCD) were significantly down-regulated. The expression levels of photosynthesis genes were also affected. Y2H and BIFC assays indicated that NRL3 interacts directly with NAL9/VYL to regulate leaf morphology in rice. Thus, NRL3 plays an important role in leaf morphogenesis and chlorophyll accumulation, and can be used as a new gene resource for constructing improved rice.