Water lily (Nymphaea spp.) is a perennial aquatic flower plant. We investigated color of 57 hardy water lily cultivars by the Royal Horticultural Society Colour Chart (RHSCC) and International Commission on Illumination CIEL^*a^*b^* scale. High-performance liquid chromatography (HPLC) with photodiode array detection (DAD) and HPLC electrospray ionization mass spectrometry (HPLC-ESI-MSⁿ) identified 14 anthocyanins. Eight compounds were identified in the petals of 119 hardy water lily cultivars for the first time. Multiple linear regression revealed that Dp3Ga, Dp3galloylGa, Cy3Ga(1→2)Ga and Cy3galloylGa compounds were key pigments in petal color. We discuss differences in anthocyanin components between hardy and tropical water lily and blue color breeding of hardy water lily.

The formation and maintenance of the cytotype mixture in plant natural populations has been found related to genetic and epigenetic variations of genomes. We investigated the patterns of genetic variation, genetic structure and methylation levels, as well as epigenetic differentiation, of a cytotype mixture population of the Actinidia chinensis complex by amplified fragment-length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP). The mixture population had high genetic and epigenetic diversity. The relationship between population genetic diversity and altitude but not epigenetic diversity and altitude was significant (P<0.05). As well, patterns of genetic and epigenetic variation were not positively correlated. Analysis of molecular variance revealed that most genetic and epigenetic variations occurred within ploidy races (97.65% vs 99.84%, P<0.05). Neighbor-joining tree analysis based on AFLP analysis revealed that the same ploidy individuals clustered preferentially, with no obvious cluster based on ploidy levels in the MSAP tree. The total methylation level in the cytotype mixture population was 24.86%. Moreover, tetraploids and hexaploids showed more variation than diploids in genomic methylation, including increase and loss of methylation loci. We provide a theoretical basis to understand the formation and maintenance mechanism in the cytotype mixture population of A. chinensis.

We used the homolog search strategy or RACE to obtain 5 precursor microRNAs (miRNAs) of larch, Larix leptolepis. Mature miRNAs shared high similarity among plant species, and non-mature sequences showed distinct similarity related to genetic relationships. Expression profiles of the 5 precursor and mature miRNAs were examined during 8 developmental stages with quantitative RT-PCR. The expression of precursor and mature miRNAs changed dynamically during developmental stages, with major peaks in expression for mature miRNAs in late cotyledonous embryos, which might be associated with promoting embryo dormancy. However, miR397 and miR408 showed minor peaks in expression at PEMIII, miR398 at the early single embryo stage, and miR156 and miR166 at the early cotyledonous embryo stage, which might be related to regulation to maintain a thin cell wall, proton transfer between photo systems, and formation of shoot meristem. However, the expression of mature miRNAs was not linearly associated with that of precursor miRNAs, which might be regulated at several levels. Our study sheds light on miRNA evolution, expression regulation of mature miRNAs, and regulation of somatic embryogenesis in larch.

Plants have developed various adaptive mechanisms to drought, salt, temperature and other stresses. Receptor-like kinases play significant roles in plant growth regulation and responses to stresses. We found that a receptor-like kinase with an S-locus domain, OsSRL, might be involved in drought stress response in rice. Downregulation of OsSRL expression by RNA interference produced enhanced drought tolerance and increased seedling survival rate, chlorophyll content and fresh weight as compared with control plants after drought stress treatment. The expression of OsSRL was induced by 30% PEG and 100 μmol·L^–1 abscisic acid. Knocking down OsSRL expression enhanced the expression of drought-response genes RAB16A and LEA3. OsSRL was expressed in plumule, radicula, root, node, and flower. These data suggest that OsSRL, as a receptor kinase with an S-locus domain, may play roles in drought stress tolerance in rice.

Ca²⁺ ions play an essential role in various plant developmental processes and in plant response to environmental stimuli. Plants have evolved a diversity of unique proteins that bind Ca²⁺. Calcineurin B-like proteins (CBLs) represent one of the main classes of Ca²⁺ sensors in plants. There are 10 members of CBLs in rice genome. Here, we used western blot analysis to examine the expression patterns of CBLs in rice leaves at different developmental stages under normal growth conditions. We then investigated the expression of CBLs at different time-points in rice incompatible responses against Xanthomonas oryzae pv. oryzae (Xoo) mediated by bacterial blight-resistant gene Xa21. The expression of OsCBL-1, -3, -5, -9 and -10 changed in incompatible responses. Furthermore, the expression of CBL proteins differed among compatible and incompatible interaction and mock controls, which suggests that CBL proteins may play roles in the interaction between rice and Xoo.

We investigated the effect of 30-day NaCl treatment on chlorophyll fluorescence variables, chlorophyll content and water potential in 4 legume seedlings, Amorpha fruticosa, Hedysarum scoparium, Caragana korshinskii and Alhagi sparsifolia, introduced in Tazhong Botanical Garden, Xinjiang, northwestern China. NaCl did not change chlorophyll fluorescence values, chlorophyll content, or leaf water potential in C. korshinskii and A. sparsifolia, but the results were opposite for A. fruticosa and H. scoparium. C. korshinskii and A. sparsifolia showed more stable photosynthetic and physiological characteristics than A. fruticosa and H. scoparium with NaCl. Leaf chlorophyll content and water potential were related in part to chlorophyll fluorescence values with 30-day NaCl treatment and may be used to indicate plant responses to NaCl.

We investigated the effect of moderate NaCl on photosynthesis and water absorption in arrowleaf saltbush (Atriplex triangularis) under PEG-induced osmotic stress to understand the effect of NaCl on plant adaptation to drought stress. PEG-induced osmotic stress led to reduced water absorption and chlorophyll content, injured photosystem and growth and reduced biomass. The addition of NaCl at 10–40 mmol·L^–1 could reduce water potential and osmotic potential, maintain a high turgor, alleviate the destructive effect of osmotic stress to the photosystem, ensure a relatively high rate of photosynthesis and plant growth, and thus increase the adaptability of the plant to osmotic stress.

Phaeocystis globosa frequently causes extensive harmful algal blooms in coastal waters of China. It has unusual life cycles, transferring between solitary cell and colonies. Solitary cells are generally a few microns in diameter, but colonies are up to 3 cm in diameter. The giant colony may result in its unique structure and cell distribution. We measured the colony diameter, colony-cell abundance and solitary-cell abundance in P. globosa (Shantou strain, isolated from South China Sea in 1997) to investigate the relationship of colony architecture and cell distribution. The results showed that colony is the dominant form during the polymorphic life cycle of P. globosa, with contributions of 38% to 95% to total biomass, especially in the late exponential and stationary phases, when colony-cell abundance assumed absolute superiority over solitary cells. Log colony-cell abundance increased with log colony diameter with the slope of 1.34 on the regression line; whereas the value was significantly lower than those in the previous studies. Therefore, the colony of P. globosa (Shantou strain) contains relatively fewer cells per unit surface area, which means the Shantou strain differed from other strains in colony architecture and cell distribution. P. globosa from Shantou can form a giant colony, which effectively protects against predators and may significantly influence the food web structure and function in regions with P. globosa blooms.

Abscisic acid (ABA), as one of the pivotal plant hormones, is essential in mediating plant growth and development and responding to biotic or abiotic stress in plants. Recent breakthroughs in screening for and confirming the ABA receptor have made great contributions to elucidating the pathways of ABA signaling transduction. Here, we offer a brief introduction of the advances in research into several candidates of ABA receptors, including ABA-binding protein/H subunit of Mg-chelatase (ABAR/CHLH), G protein-coupled receptor 2, GPCR-type G protein 1/2, and pyrabactin resistant/PYR-like/regulatory component of ABA (PYR/PYL/RCAR). We emphasize the putative ABA signaling transduction pathway of ABAR/CHLH or PYR/PYL/RCAR as a receptor. These progresses could be useful for studying ABA receptors and the pathways of ABA signaling transduction.

Folates are water-soluble B-vitamins that contain tetrahydrofolate (THF) and its derivatives. In plants, they are essential cofactors in C1 metabolism, being involved in the formation of purines and thymidylates for DNA synthesis, production of amino acids and proteins. They play a central role in the methyl cycle. Novel functions of folates in plants have been discovered recently. For example, folates regulate gene expression by the riboswitch, work as the electron donor when phenylalanine is converted to tyrosine, and harvest light as the coenzyme of photolyase and plant cryptochrome. Moreover, folate is involved in chlorophyll biosynthesis and oxidative tolerance of seeds, for example. We review these discoveries and give prospects for plant folate research.

Autophagy is a highly conserved biological progress in degradation of the cell components and has key roles in starvation, senescence and infection by pathogens. Moreover, reactive oxygen species (ROS) is a byproduct of higher plants during normal and stress conditions and plays an important role in regulation of growth and development and programmed cell death during stress response. Recent research has shown that ROS and autophagy both regulate programmed cell death in the hypersensitive reaction during infection by pathogens, growth and development and stress adaptation. We discuss the signal interaction between ROS and autophagy in plants, including species and characteristics of ROS, the molecular basis of plant autophagy, and  functions of ROS in plant autophagy.

The hypersensitive reaction is an important process in plant disease resistance. Similar to apoptosis in animals, it is programmed cell death (PCD) process in plants. Caspases (cysteine-dependent aspartate-specific proteases) play a central role in animal apoptotic pathways. No orthologous proteins of caspases have been found in plants, but a group of proteins with similar structures, termed metacaspases, have been found. In plants, some PCD processes depend on metacaspases, and others do not. We discuss researches into the structure and function of metacaspases. The biological functions of metacaspases and their roles in PCD pathways in plants remain to be explored.