Aminolevulinic acid (5-ALA) and dihydroporphyrin iron chelates (DHFe) play roles in plant growth regulation under normal and stressful conditions. However, definitive data on their roles in regulating chlorophyll synthesis in wheat are lacking. In this study, the optimal concentrations for foliar-spray application of 5-ALA and DHFe to promote wheat seedling growth and leaf chlorophyll content were assessed. The optimal concentrations of 5-ALA or DHFe (50 mg/L and 0.01 mg/L, respectively) were applied as foliar sprays to seedlings of wheat ‘Bainong 4199’ (high light efficient) and ‘Zhoumai No. 18’ (average light efficient) under different light intensities. Chlorophyll precursor contents and activities of three chlorophyll synthesis-related enzymes were altered, and the combined application of 5-ALA and DHFe more strongly increased the leaf chlorophyll content. 5-ALA significantly increased the contents of the chlorophyll precursors porphobilinogen, uroporphyrinogen III, protoporphyrin IX, and magnesium-protoporphyrin IX, and the activities of 5-amino-ketovalerate dehydratase and uroporphyrinogen III synthase. DHFe resulted in an increase in chlorophyll content but a significant decrease in chlorophyllase activity and protochlorophyllide content. 5-ALA promoted the synthesis of chlorophyll precursors by regulating the activities of 5-amino-ketovalerate dehydratase and uroporphyrinogen III synthase. DHFe decreased chlorophyllase activity, thereby slowing chlorophyll degradation and increasing the chlorophyll content.

CIPK (calcineurin B-like-interacting protein kinase) is a kind of serine/threonine protein kinase widely existing in plants, and it plays an important role in plant growth and development and stress response. To better understand the biological functions of the GhCIPK23 gene in upland cotton, the coding sequence (CDS) of the GhCIPK23 gene was cloned in upland cotton, and its protein sequence, evolutionary relationship, subcellular localization, expression pattern and cis-acting elements in the promoter region were analyzed. Our results showed that the full-length CDS of GhCIPK23 was 1368 bp, encoding a protein with 455 amino acids. The molecular weight and isoelectric point of this protein were 50.83 KDa and 8.94, respectively. The GhCIPK23 protein contained a conserved N-terminal protein kinase domain and C-terminal regulatory domain of the CIPK gene family member. Phylogenetic tree analysis demonstrated that GhCIPK23 had a close relationship with AtCIPK23, followed by OsCIPK23, and belonged to Group A with AtCIPK23 and OsCIPK23. The subcellular localization experiment indicated that GhCIPK23 was located in the plasma membrane. Tissue expression analysis showed that GhCIPK23 had the highest expression in petals, followed by sepals, and the lowest in fibers. Stress expression analysis showed that the expression of the GhCIPK23 gene was in response to drought, salt, low-temperature and exogenous abscisic acid (ABA) treatment, and had different expression patterns under different stress conditions. Further cis-acting elements analysis showed that the GhCIPK23 promoter region had cis-acting elements in response to abiotic stress, phytohormones and light. These results established a foundation for understanding the function of GhCIPK23 and breeding varieties with high-stress tolerance in cotton.

Gynostemma pentaphyllum (Thunb.) Makino (G. pentaphyllum) is used in traditional Chinese medicine to stimulate immune responses and reduce blood lipid concentrations, and has broad market growth prospects. In this study, a nutrient liquid culture method has been modified by adding nitrogen and or chemical mimic of saponin precursor to stimulate rooting from stem cuttings. Furthermore, total nitrogen concentration and ammonia/nitrate ratio in the nutrient solution has been optimized; And, the concentration of three ginsenosides precursors that applicated in nutrition solution together with total nitrogen and ammonium/nitrate ratio were studied. The results showed that, after 10 days of culture, adventitious roots developed from stem cuttings to form complete regenerated plantlets. The addition of 1 mg·L^-1 indole acetic acid in hydroponic solution could effectively increase the length and number of adventitious roots. The optimal total nitrogen concentration in the nutrient solution for increase in fresh biomass of G. pentaphyllum was 7.0 mmol·L^-1 and the optimal ammonium/nitrate ratio was 2:3 for increase in the plant fresh weight, and chlorophyll a, chlorophyll b, and total chlorophyll contents of G. pentaphyllum rooted cuttings. Addition to the nutrient solution of three chemical mimics of saponin precursors sodium acetate (0.5 mmol·L^-1), geraniol (0.5 mmol·L^-1), and DL-mevalonolactone (0.3 mmol·L^-1) increased the content and yield of total saponins.