Plant science in China has been developing rapidly in 2012. Chinese scientists reported a lot of original research findings of high level in various aspects of plant biology, including the research into plant genome, the signaling pathway of plant innate immune resistance, the mechanism of DNA demethylation and DNA double-strand break repair in plants, and so on. This review aims to provide an overall picture of plant research in China and highlights some of the important findings in 2012.

We studied the biomass allocation and clonal growth characteristics of Bambusa pervariabilis × Dendrocalamopsis daii and B. rigida in Changning County, Sichuan Province. The biomass of stem was higher but those of branches and leaves lower in B. rigida than B. pervariabilis × D. daii, so B. rigida had greater nutrient assimilation efficiency. The reproduction ratio of both species did not differ. However, the degenerated shoot ratio was lower for B. rigida than B. pervariabilis × D. daii, so reproduction of B. rigida was more efficient. The rhizome length was longer for B. rigida than B. pervariabilis × D. daii, so B. rigida had faster expansion ability. The growth characteristics of new bamboo were significantly associated with quantity, size and age structure of mother bamboo in B. pervariabilis × D. daii and B. rigida forests. B. rigida had a K-strategy reproductive strategy, for strong ability to produce shoots with higher ratio of grown bamboo, and B. pervariabilis × D. daii had an R-strategy, with higher ratio of shoot production and degeneration. The numbers and diameters of new bamboo at breast height were strongly correlated with that of the mother bamboo, which could be simulated with a linear model.

Amorphophallus konjac plants with strong resistance to soft-rot disease were identified from the A. konjac field in Changyang, Yichang. Karyotype analysis showed that the number of chromosomes in resistant plants were consistent with that in common A. konjac plants (susceptible), and both were 2n=26. Resistant plants were compared with susceptible A. konjac plants for disease resistance. Soft-rot-resistant plants showed stronger resistance against Erwinia carotovora var. carotovora than susceptible plants did. ELISA revealed hormone levels induced within 30 h after infection with E. carotovora. However, susceptible plants showed higher levels of jasmonate and salicylic acid than resistant plants did. These results imply a different disease resistance mechanism in resistant A. konjac plants, which can be examined by further studies.

We investigated the effect of different Cu²⁺ concentrations in the root medium on root growth, reactive oxygen species (ROS) accumulation, antioxidative response, DNA damage, plasma membrane integrity and cell viability in roots of Arabidopsis thaliana, and the toxicity range was explored with split-root technique. Primary root length was significantly inhibited. Cu²⁺ enhanced the activities of antioxidant enzymes, induced ROS accumulation and DNA damage, and reduced plasma membrane integrity. Cell death was significantly increased with increased concentration of Cu²⁺. ROS accumulation was significantly and positively correlated with the activities of total superoxide dismutase, catalase, peroxidase and ascorbate peroxidase. ROS accumulation increased linearly with DNA damage, plasma membrane integrity and cell viability. In the split-root experiment, root growth was inhibited in culture medium supplemented with 75 μmol·L^–1 Cu²⁺; however, roots were not inhibited in medium without supplementary Cu²⁺. ROS accumulation and cell death took place in only half the dish, so Cu²⁺ toxicity was local, not systemic. Local ROS accumulation in roots likely mediates the cell death caused by Cu²⁺ stress.

Brassica napus (rape) seedlings were treated with different concentrations of strontium (1, 5, 10, 20 mmol·L^–1SrCl₂) for 21 days, and the effect of strontium on the photosynthesis of rape leaves was investigated by chlorophyll fluorescence induction dynamics and photosynthetic gas exchange parameters. Photosystem II potential activity, actual photochemical efficiency, apparent photosynthetic electronic transfer rate, and photochemical quenching increased with low strontium concentration (1, 5 mmol·L^–1) but decreased with high concentration (10, 20 mmol·L^–1). Minimum fluorescence and non-photochemical quenching did not change significantly with low strontium concentration but significantly increased with high concentration. Net photosynthetic rate and transpiration rate of leaves significantly increased with low strontium concentration but decreased with high concentration; stomatal conductance significantly decreased with increasing strontium concentration; intercellular CO₂ concentration increased with high concentration. Chlorophyll content significantly increased with low strontium concentration and decreased with high concentration. Thus, low strontium concentration could improve photosynthetic function of rape seedlings and increase photosynthetic efficiency, but a high concentration can harm the photosynthetic apparatus and significantly inhibit photosynthetic efficiency.

Phosphoenolpyruvate carboxykinase (PEPCK) is ubiquitous in flowering plants but present in only certain tissues and cells. It is highly regulated by phosphorylation (which can be regulated by light) and metabolites. In plants, ATP-dependent PEPCK often generates PEP, which plays roles in many biological processes. PEPCK may be involved in these processes indirectly, including gluconeogenesis after germination of triglyceride-storing seeds and fruit ripening; photosynthetic CO₂-concentrating mechanisms of C₄ and crassulacean acid metabolism plants; cellular pH homeostasis; and nitrogen metabolism. This paper reviews the regulation of PEPCK activity in plants and its physiological functions.

Abscisic acid is an important phytohormone that has many functions in higher plants, including seed germination, development and dormancy; regulating stomatal movement; and improving stress tolerance. However, two major drawbacks have restricted its application as a plant growth regulator for agrochemical use: It is easily metabolized in plants and this leads to concomitant loss of biological activity and geometry (2Z, 4E) of its 2, 4-pentadienoic acid moiety, which is crucial for its hormonal activities to be readily isomerized to biologically inactive (2E, 4E) isomers by light. Accordingly, synthesis of new abscisic acid analogues with higher activity and better photo-stability is important. This paper reviews research advances in the chemical and biological activities of antimetabolic and photostable analogs of abscisic acid.

MicroRNA (miRNA) chip and sequencing have been used to detect miRNAs in species. With the discovery of more miRNAs, miRNA target genes are the key to study miRNA biological function. Finding miRNA target genes mainly relies on computational prediction, AGO protein co-immunoprecipitation and luciferase. Deep sequencing, or degradome sequencing, can be used for high-throughput identification of targets of miRNAs. The method includes deep sequencing, bioinformatic analysis and 5'-rapid amplification of cDNA ends. It has been successfully used for global identification of miRNA-target RNA pairs in Arabidopsis thaliana, Oryza sativa and Physcomitrella patens. This paper reviews research progress in degradome sequencing in plant miRNA target study and discusses trends in further application of degradome sequencing.