Integration of Metabolome and Transcriptome Studies Reveals Flavonoids, Abscisic Acid, and Nitric Oxide Comodulating the Freezing Tolerance in Liriope spicata.

Liriope spicata is an evergreen perennial ornamental groundcover with a strong freezing tolerance. However, the molecular mechanism underlying the freezing tolerance in L. spicata remains unclear. In this study, a comprehensive investigation of L. spicata freezing tolerance was conducted at the levels of physiology and biochemistry, metabolite, and transcript during the stress treatment. There were 581 unique differentially expressed metabolites (DEMs) and 10,444 unique differentially expressed genes (DEGs) between freezing treatment and normal cultured plant in leaves. Integrated analysis of metabolomics and transcriptomics showed that flavonoid biosynthesis, carbohydrate metabolism, amino acid metabolism, lipid metabolism, and signal transduction pathways were prominently enriched in response to the freezing stress in L. spicata. Now, we identified genes and metabolites involved in the flavonoid pathway, abscisic acid (ABA) biosynthesis, and the oxidative synthesis pathway of nitric oxide (NO), which may form a regulatory network and play a synergistic effect in osmotic adjustment, reactive oxygen species (ROS) homeostasis, and stomatal closure under freezing stress. These results offer a comprehensive network of flavonoids, ABA, and NO comodulating the freezing tolerance in L. spicata.

Engineering Lignin Nanomicroparticles for the Antiphotolysis and Controlled Release of the Plant Growth Regulator Abscisic Acid.

Lignin is the most abundant aromatic biopolymer in nature and is a major byproduct from the paper industry. The unlocking of lignin's potential for high-value applications has gained increasing attention in recent years. In this study, alkali lignin (AL), with a rigid conjugated structure and amphiphilic property, was used as a sustainable and eco-friendly encapsulation material for the protection and controlled release of photosensitive abscisic acid (ABA), an important and widely used plant growth regulator. Cetyltrimethylammonium bromide (CTAB) was used to induce the formation of AL-CTAB nanomicroparticles by self-assembly. The size and morphology of AL-CTAB particles were modified by changing the AL concentration and the dispersion agent. AL (0.3 M) dissolved in tetrahydrofuran could form a uniform size (300 nm) of particles with a regular spherical structure. Subsequently, ABA was loaded on the prepared nanomicroparticles to synthesize the capsule formulation of ABA@AL-CTAB. The controlled-release behavior and the antiphotolysis performance as well as the thermal stability of ABA@AL-CTAB were proved to be superior. Lasting inhibition of Arabidopsis and rice seed germination by ABA@AL-CTAB under light irradiations implied protection of ABA from photolysis. In addition, ABA@AL-CTAB could effectively regulate plant stomata, thereby increasing plant drought resistance. Overall, lignin is suitable for the preparation of agrochemical formulations with excellent controlled release and antiphotolysis performances.

[Effects of mepiquat chloride on inorganic elements contents in seeds of transgenic insect-resistant cotton determined by ICP-MS].

To evaluate the effects of a worldwide used plant growth regulator mepiquat chloride on the nutrition value and safety of seeds of transgenic Bt cotton, inorganic element components and contents in seeds of Bt cotton (Gossypium hirsutum cv. Guoxin 6) under field condition were determined using ICP-MS. In Bt cotton seeds, 54 kinds of inorganic elements were identified by ICP-MS, and 5 kinds of major elements, K, P, Mg, Ca and Na, were in range from 138.3 to 13,835.1 microg x g(-1). The contents of 14 kinds of microelements were determined as in descending order of Si, B, Mn, Sr, Zn, Ni, Cu, Mo, Fe, Co, Se, V, I and Sn, in the range from 14.2 ng x g(-1) to 81.7 microg x g(-1). Five kinds of heavy metals were detected with the contents from 0.14 to 55.3 ng x g(-1), and their order from high to low is Pb, Cd, Cr, As and Hg. Other 30 kinds of elements were also detected in Bt cotton seeds by ICP-MS, including Rb, Be, La, Ce, Pr, Nd, Sm, Gd, Ge, Rh, Ag, Sb, W, U and Y. Foliar application of mepiquat chloride significantly reduced the contents of Ca, Fe, Si, Mn, Co, Ni, Cu and I, and remarkably decreased heavy metals Pb, Cd and Cr in the cotton seeds, by 68%, 67% and 54% respectively. While mepiquat chloride did not change the contents of most major and micro elements, it heightened 8 kinds, but lowered 7 kinds of the other 30 trace elements. This research indicated that mepiquat chloride application strengthened the security regarding the cotton seed as the material of cooking oil.

[Application of ICP-AES to detection of inorganic elements in roots bleeding sap from maize and soybean plants].

The constituents of the roots bleeding sap are an important index characteristic of roots activity and roots-shoots relationship. To compare the differences between the constituents of roots bleeding sap from maize and soybean plants, roots bleeding saps were collected from maize (Zea mays L. cultivar 3138) and soybean [Glycine max (L.) Merr. cultivar Ludou 11] plants at different growth and development stages under field condition, and the inorganic elements were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results indicated that both the constituents of inorganic elements and flow intensities were various between roots bleeding saps from maize and soybean plants at different growth and development stages. The flux of inorganic elements in roots bleeding sap showed different trends with progress in plants growth and development. In the roots bleeding sap from maize, the predominant inorganic elements were K, Ca, Mg, P, Na, Si, Zn, Mn and Fe, with flux ranging from 1 to 1 851.5 microg x h(-1) x plant(-1). The flux of B, Cu and Mo was relatively lower and less than 1 microg x h(-1) x plant(-1), while none of the elements of Co, Cd, Ba, Pb, Sr and As could be detected, and was estimated to be lower than 0.01 microg x h(-1) x plant(-1) based on the detection limit. The flow of most inorganic elements showed decreasing trends with plant development progressing from booting to grain filling stage. In the roots bleeding sap from soybean, Ca, Mg, K, P, Na, Zn, Mn, Fe and Cu were found as predominant inorganic constituents, ranging from 1 to 1 158 microg x h(-1) x plant(-1). The flow of both B and Mo was found lower than 1 microg x h(-1) x plant(-1), and none of Si, Co, Cd, Ba, Pb, Sr and As could be found. With the growth and development, different inorganic elements showed various changing pattern.

[Effect of HKL-4 on active oxygen metabolism and photochemical efficiency in licorice leaf].

OBJECTIVE: To study the effects of HKL-4 on physiological changes during growth of leaves. METHOD: Using licorice (Glycyrrhiza uralensis) as material, the effects of HKL-4 on active oxygen metabolism and photochemical efficiency in licorice leaf were determined under field condition. RESULT AND CONCLUSION: The contents of chlorophyll, activity of SOD and CAT increased, while the MDA contents in leaves decreased. The senescence was delayed, so that the photochemical efficiency (Fv/Fm) was increasing comparing to the control.

[Effects of fertilization on cotton growth and nitrogen use efficiency under salinity stress].

Cotton (Gossypium hirsutum) was raised at different salinity levels (0, 0.15% and 0.30%) by irrigating with fresh- or sea-water. The effects of fertilization (N, NK, NP and NPK) on plant growth, nitrogen (N) uptake and N use efficiency were studied. The results showed that salinity and fertilization both affected the biomass, agronomic N use efficiency, N bioavailability and nitrogen accumulation of plants, and significant interaction was observed between the two factors. Fertilization could improve N use efficiency and nitrogen accumulation of plants under salinity stress, and significantly promoted the cotton yield. Among the fertilization treatments, N combined with P and K had the best effect. The benefit of fertilization was better under low salinity (0.15%) than under moderate salinity (0.3%).

Improved biological effects of uniconazole using porous hollow silica nanoparticles as carriers.

BACKGROUND: The aim of this work is to prepare a controlled-release formulation of uniconazole using porous hollow silica nanoparticles (PHSNs) as carrier, and to investigate the biological effects on rice growth. RESULTS: PHSNs with a shell thickness of ~15 nm and a particle size of 80-100 nm were synthesised through a sol-gel route using nanosized calcium carbonate particles as templates. Simple immersing (SI) and supercritical fluid drug loading (SFDL) technologies were employed to load uniconazole into PHSNs with loading efficiencies of ~22 and ~26% respectively. The prepared uniconazole-loaded PHSNs (UCZ-PHSNs) by SI and SFDL both demonstrated sustained release properties, and the latter showed better controlled release ability with a slower release rate. Compared with free uniconazole, UCZ-PHSNs exhibited a weaker growth retardation effect in the early stage but more significant retardation ability in later stages for agar-cultured rice seedlings. For the rice that grew in clay, UCZ-PHSNs demonstrated a weaker plant height retardation effect than free uniconazole at the early jointing stage by foliar spraying, but exhibited a stronger retardation capacity than free uniconazole by being applied into soil before seedling transplantation. CONCLUSION: The results indicated that the prepared UCZ-PHSNs possessed good controlled-release properties and had improved retardation effects on rice growth. It is recommended that UCZ-PHSNs be applied into soil before seedling transplantation rather than administered by foliar spraying at the early jointing stage.

[Growth vitality and pollutants-removal ability of plants in constructed wetland in Beijing region].

Nine aquatic plant species commonly found in northern China were transplanted in a horizontal subsurface flow constructed wetland in Beijing region to study their growth vitality in the wetland and their removal ability to the pollutants in domestic sewage. The results showed that the wetland's front unit had greater contribution to the COD, TN and TP removal than the rear ones, and all test plant species could grow well in the wetland. After growing for 112 days, different plant species had significant differences in their N and P contents and total biomass (P <0.05). For most species, the N and P contents were higher in underground than in aboveground part, and the biomass ratio of under-/aboveground part (U/A) was close to or exceeded 1. The accumulated N and P in the plants ranged from 1.36 to 7.89 g m(-2) and from 0.19 to 1.07 g m(-2), respectively, and the N and P accumulation in plants were more affected by plant biomass than by its N and P contents. Among the test plant species, Iris pseudacorus ranked the first in setting up the constructed wetland, followed by Typha angustifolia, Acorus calamus, and Triarrhena sacchariflora, whereas Alisma plantago-aquatica and Arundo donax were not recommended due to their sensitivity in cold winter in northern China.