Plant hormones play important roles in regulating plant growth and development. Because hormone responses are usually concentration-dependent, endogenous hormone levels must be tightly controlled. Glycosylation may be one of the important modifications modulating active hormone levels. With the cloning and identification of glycosyltransferases genes involved in glycosylation of plant hormones, the mechanism and roles of glycosylation of different plant hormones were gradually revealed. This review focuses on recent research progress in understanding enzyme activities and biological functions of glycosyltransferases for auxins, cytokinins, abscisic acids, brassinosteroids, salicylic acid and jasmonic acid. We discuss remaining questions to be answered and prospects for hormone glycosylation study.

For pollination, plants show a high degree of adaptation. To expand the area to accept pollen, wind-pollinated flowering plants form a special structure to adapt to wind-spread pollen. We investigated the morphology of styles and pollen tube growth on styles (including stigmas) for 18 species of 6 genera in Betulaceae by scanning electron microscopy. Betulaceae have two-carpel (or rarely tri-carpel in Ostrya japonica and Carpinus monbeigiana) gynoecia, usually with cylindrical styles and not well-developed stigmas. Styles have elongate epidermal cells, arranged longitudinally and tightly; styles function as stigma to receive mature pollen grains and provide a suitable germination environment. Betulaceae have two types of styles: in one, epidermal cells have bubble or tubular papillae, and the pollen tube enters the style through papilla; in the other, epidermal cells have no papillae, and the pollen tube enters the style between the epidermal cells. Whether style epidermal cells can form papillae or not, the morphology or size of papillae and the binding mode of pollen and papilla differs by tribe, gender and genus. The style epidermal cells in Betulaceae could perform the function of a stigma, receiving pollen and providing locations and conditions for pollen germination. The papillae formed by style epidermal cells in Betulaceae have the same function as in basal angiosperms, an adaptation strategy for plants with wind pollination.

Cellulose is a major structural component of the plant cell wall. Thus, understanding cellulose biosynthesis is important in plant biology and biomass production. In this study, we analyzed the phylogenetics of Arabidopsis cellulose synthesis genes (AtCESA) and their expression using the microarray data from NCBI. Furthermore, we analyzed the expression of 10 AtCESA promoter:GUS reporter genes in different vegetative and reproductive growth stages of Arabidopsis. Our results showed that AtCESA1, -3, and -6 or -6-like protein genes were probably required for primary cell-wall complexes, whereas AtCESA4, -7, and -8 protein genes were possibly involved in secondary cell-wall complexes. AtCESA1, -3, and -6 show high global expression in all tissues, whereas AtCESA4, -7, -8 are highly expressed in root, stem and leaf vein. We found 3 segmental duplication genes (AtCESA5/6, AtCESA2/9 and AtCESA1/10); AtCESA5 may be partially redundant with AtCESA6. In addition, AtCESA9 showed tissue-specific expression in meristems and flowers and may be partially redundant with AtCESA2. AtCESA genes may be important for primary and secondary cell-wall formation during different developmental stages in Arabidopsis and in different organs.

ASR (abscisic acid [ABA], stress, ripening-induced) proteins are a class of transcriptional factors involved in drought stress tolerance in many plant species. However, the regulation mechanism of ASR in banana under drought stress tolerance is not known. Previously, we screened a new ASR gene from the cDNA library of banana (Musa acuminata cv. ‘Brazilian’), designated MaASR1 (accession no. AY628102). MaASR1 expression was higher in leaves than roots under drought stress. MaASR1 was transferred into Arabidopsis thaliana and two independent transgenic lines (L14, L38) were obtained. The leaves of MaASR1 transgenic lines were smaller and thicker than those of the wild type. Survival rate and proline content were higher in L14 and L38 than in the wild type after drought treatment. Under drought stress and ABA treatment, We found that MaASR1 could enhance the sensitivity of the transgenic plants to ABA signal but did not improve ABA-dependent drought stress tolerance.

We collected 20-year-old Larix principis-rupprechtii from a plantation in Qinling to explore the contents of C, N and P and their ecological stoichiometry characteristics in fine roots, stems and needles in different seasons. The content of C increased first, then decreased and increased again throughout the growing season (May to October). The order of the mean content of C in organs was stems > needles > fine roots. The content of N in fine roots, stems and needles tended to fluctuate during the growing season. The content of P in both needles and fine roots decreased first, then increased and decreased again, then remained stable. The content of P in stems decreased first and then increased, then decreased gradually. The order of the mean content of both N and P in organs was needles > fine roots > stems. The content of N had the greatest variability in fine roots and needles throughout the growing season. The coefficient of variation (cv%) of P was greatest for stems. The variability of C in the 3 organs was the smallest. The changes in C:N and C:P ratios were opposite to that of corresponding N, P content in fine roots, stems and needles. The ratio of N:P peaked in stems and was minimal in fine roots. The order of the cv% for C:N throughout the growing season was fine roots < stems < needles and for both C:P and N:P was fine roots < needles < stems. Factorial analysis of variation for each parameter, with sampling season and organs as independent variables, showed that the content of C, N and P and C:N mass ratio mainly depended on the organ. C:P and N:P mass ratios were mainly determined by the interaction of organs and season. The mass ratio of C:N:P was similar in fine roots (369:7:1) and needles (309:10:1). The characteristics of C, N and P stoichiometry were relatively stable in fine roots. Quantitative characteristics in fine roots were affected less in different seasons in L. principis-rupprechtii in Qinling, which helps in analysis of the ecological system.

Bryophytes (mosses) are sensitive to air pollution because of their unique morphological and physiological characteristics. They are widely used to monitor environmental quality and changes in suburbs and urban areas. We evaluated the capacity of bryophytes to absorb and accumulate heavy metals by analysis of heavy-metal content in mosses and soil at Mt. Lao, Qingdao. Grimmia pilifera is a good biomonitor because of its wide distribution and good capacity to absorb and retain heavy metals such as Pb, Zn, Cu and Cd. Taxiphyllum taxirameum, Hypnum plumaeforme and Entodon luridus, widely distributed in Qingdao, also have high capacity to absorb and accumulate heavy metals. We established a valuable method to monitor atmospheric deposition of heavy metals in Qingdao using the moss biomonitor technique.

Scattering and backscattering properties were measured for 4 main fresh water alga species cultured in the laboratory: Microcystis aeruginosa, Chlorella vulgaris, Cyclotella meneghiniana and Cryptomonas ovata. Chlorophyll a-specific scattering and backscattering were used to represent scattering ability. M. aeruginosa had the strongest scattering and backscattering ability, followed by C. meneghiniana, and C. vulgaris had the weakest. M. aeruginosa and C. meneghiniana showed greater backscattering ability than C. vulgaris and C. ovata. The main factor affecting backscattering was the ratio of chlorophyll a to phycocyanin content. Backscattering coefficient varied with chlorophyll a content and chlorophyll a proportion to total pigment. We found a good correlation between cell size and backscattering coefficient.

The plant transient expression system plays an important role in analysis of subcellular localization, interaction and promoter activity of protein. Here, we established a transient expression system in cotton cotyledons based on Agrobacterium-mediated transformation with GUS and eGFP as reporter genes. We investigated the optimal conditions for the system, including cotyledon growth time, Agrobacterium concentration, injection volume and co-culture time. The highest efficiency of exogenous gene expression was 50 μL Agrobacterium LBA4404 or GV3101 with OD₆₀₀=0.5 and co-culture for 2–3 days in cotton cotyledons germinated for 6 days. The transient expression system is convenient and only needs 8 to 13 days to detect exogenous protein expression from germination to results. The system may have a good application for analysis of gene function in cotton.

We used leaves (12-d-old) of Rosa hybrida as explants and MS medium to examine the effect of combinations and concentrations of growth regulators on callus, adventitious buds and root induction. The optimal medium for inducing calli was MS medium with 3.0 mg·L^–12,4-D+1.0 mg·L^–16-BA; 100% callus induction ratio was obtained. 6-BA played a key role in adventitious bud induction. Adventitious buds were regenerated from calli on MS medium containing 1.0 mg·L^–16-BA, (0.05–0.5) mg·L^–1NAA and (0.02–0.2) mg·L^–1TDZ. The callus redifferentiation ratio was about 92.6% in MS medium supplied with 1.0 mg·L^–16-BA+0.1 mg·L^–1NAA+0.02 mg·L^–1TDZ. Auxin is an important factor for inducing rooting; 100% rooting was obtained on 1/4 MS medium containing 0.1 mg·L^–1NAA. We established a tissue culture and high-frequency regeneration system of R. hybrida.

Newly born stems with axillary buds of eminent Acacia melanoxylon (AMY12004) were used as explants and cultured on MS after sterilization. The aseptic leaf, petiole and stem of germinated axillaries were used to induce callus, and high-frequency regeneration systems were established via indirect organogenesis. The optimal material for callus induction was the stem, the optimal medium for induction was MS+1.5 mg·L^–16-BA+0.2 mg·L^–1NAA+3 sucrose, and the optimal medium for redifferentiation was MS+2.0 mg·L^–16-BA+0.5 mg·L^–1NAA+3%sucrose. The callus induction rate, redifferentiation rate and regeneration coefficient was 93.33%, 79.17% and 9.58, respectively. The optimal rooting medium was MS+0.5 mg·L^–1IBA+0.5 mg·L^–1NAA+4%sucrose and the highest rooting rate was 96.05%; the transplant survival rate was 81.40%.

Near-infrared reflectance spectroscopy was used for rapid and nondestructive determination of proteins in Epimedium. The calibration model was developed under the following conditions: second-derivative, standard multiplicative scatter correction, principal component analysis and modified partial least-squares regression. R squared, standard error of cross-validation and 1 minus variance ratio values were 0.923, 0.554 and 0.717, respectively. Protein content did not differ by near-infrared reflectance spectroscopy or Kjedahl nitrogen determination methods, and their relationship was close (R²=0.933 9). The proposed near-infrared reflectance spectroscopy method is a simple analytical technique with satisfactory accuracy and repeatability (RSD=0.937%). Protein content in 8 species of Epimedium were determined by near-infrared reflectance spectroscopy. The method shows great potential for protein assay in quality control and resource utilization of Epimedium.

Extracellular ATP (eATP) is an important signaling agent in plant growth and the defense response to environmental stimuli. eATP has dual functions in plant cell signaling, which largely depend on its concentration in the extracellular matrix (ECM). A lethal level of eATP (extremely low or high) causes cell death, whereas a moderate level benefits plant growth and development. Ecto-apyrases help controlling eATP content in the ECM and thus contribute to mediating the plant growth and defense response to environmental stress. We summarize the discovery, generation and removal of eATP; the receptors of eATP and eATP signaling in plants; and highlight the physiological function of eATP under stress. We also give a brief outlook of future research of eATP in plants.

Plant secondary metabolites are important natural sources for drugs and chemical raw materials. The formation of these metabolites is closely related to the normal growth and adaptation to environments by plants and could be regulated by a variety of factors. As an endogenous hormone in plants, ethylene plays important roles in regulating most plant physiological processes such as growth, development, stress resistance and secondary metabolite biosynthesis. Here, we review the signal transduction mechanism and regulatory effects of ethylene, especially its dual regulatory effects, on the formation of plant secondary metabolites, namely, how ethylene promotes the biosynthesis of secondary metabolites within a range of concentration in plants but has an inhibitory effect on the formation of secondary metabolites outside of a certain threshold of concentration. We give prospects for further research in this field.