The Biogenesis of the Photosynthetic Apparatus and the Activity of Chlorophyll Biosynthesis in a Plastome Mutant of Sunflower

It was demonstrated that, in the phenotypically colorless leaves of a sunflower (Helianthus annuusL.) plastome mutant with a heavily reduced level of chlorophyll, all pigment–protein complexes of the photosynthetic apparatus typical for the wild type were present. However, the ratio between them was changed. During aging of the mutant leaves, pigment–protein complexes of photosystem I were destroyed first followed by those of photosystem II. Chlorophyll a/b-containing light-harvesting complex II turned out to be the most stable. This conforms to an increased content of lutein and violaxanthin in mutant leaves. A synchrony of the decreases in the chlorophyll and 5-aminolevulinic acid (ALA) contents throughout all ontogenetic stages of the colorless mutant leaves made it possible to suggest that a decrease in the synthesis and resynthesis of chlorophyll during the formation and development of such leaves is caused by the inhibition of an initial stage of this process, namely, the biosynthesis of ALA molecules. The activity of the enzymes converting ALA into protochlorophyllide did not limit chlorophyll biosynthesis. Possible mechanisms controlling the synthesis of ALA destined for chlorophyll formation are discussed.     

A taxonomic study on Saxifraga ser. Radioflorae (Saxifragaceae) in Japan,the Kuril Islands and Kamchatka

Plants of Saxifraga ser. Radioflorae (A. M. Johnson) Zhmylev, now commonly regarded as belonging to the genus Micranthes, including Saxifraga fusca Maxim. and Saxifraga purpurascens Kom. (Saxifragaceae), distributed from Kamchatka to southern Japan through the Kuril Islands, are here taxonomically revised on the basis of floral morphology. The results suggest that the plants can be divided into three groups: 1) those from Kamchatka and the northern Kurils, 2) those from Kunashiri to the Japanese archipelago, through Hokkaido and Honshu, and 3) those from the southern Kurils from Chirpoi to Etorofu Islands. Leaf characteristics and habitat preferences also correlate with these groupings. The first group is identified as Micranthes ohwii ( = Saxifraga purpurascens Kom.), and the second group as M. fusca. The third group is similar to M. fusca in floral proportions, but has petals with non‐revolute margins, larger floral discs and disc and filaments developing throughout anthesis. The third group may be derived from M. fusca, adapted to the coastal environment.     

Factors Associated with Unplanned Dialysis Starts in Patients followed by Nephrologists: A Retropective Cohort Study

The number of patients starting dialysis is increasing world wide. Unplanned dialysis starts (patients urgently starting dialysis in hospital) is associated with increased costs and high morbidity and mortality. Risk factors for starting dialysis urgently in hospital have not been well studied. The primary objective of this study was to identify risk factors for unplanned dialysis starts in patients followed in a multidisciplinary chronic kidney disease (CKD) clinic. We performed a retrospective cohort study of 649 advanced CKD patients followed in a multidisciplinary CKD clinic at a tertiary care hospital from January 01, 2010 to April 30, 2013. Patients were classified as unplanned start (in hospital) or elective start. Multivariable logistic regression was used to identify variables associated with unplanned dialysis initiation. 184 patients (28.4%) initiated dialysis, of which 76 patients (41.3%) initiated dialysis in an unplanned fashion and 108 (58.7%) starting electively. Unplanned start patients were more likely to have diabetes (68.4% versus 51.9%; p = 0.04), CAD (42.1% versus 24.1%; p = 0.02), congestive heart failure (36.8% versus 17.6%; p = 0.01), and were less likely to receive modality education (64.5% vs 89.8%; p < 0.01) or be assessed by a surgeon for access creation (40.8% vesrus78.7% p < 0.01). On multivariable analysis, higher body mass index (OR 1.07, 95% CI 1.02, 1.13), and a history of congestive heart failure (OR 2.41, 95% CI 1.09, 5.41) were independently associated with an unplanned start. Unplanned dialysis initiation is common among advanced CKD patients, even if they are followed in a multidisciplinary chronic kidney disease clinic. Timely education and access creation in patients at risk may lead to lower costs and less morbidity and mortality.     

Cracking the case: Seed traits and phylogeny predict time to germination in prairie restoration species

Traits are important for understanding how plant communities assemble and function, providing a common currency for studying ecological processes across species, locations, and habitat types. However, the majority of studies relating species traits to community assembly rely upon vegetative traits of mature plants. Seed traits, which are understudied relative to whole‐plant traits, are key to understanding assembly of plant communities. This is particularly true for restored communities, which are typically started de novo from seed, making seed germination a critical first step in community assembly and an early filter for plant establishment. We experimentally tested the effects of seed traits (mass, shape, and embryo to seed size ratio) and phylogeny on germination response in 32 species commonly used in prairie grassland restoration in the Midwestern USA, analyzing data using time‐to‐event (survival) analysis. As germination is also influenced by seed dormancy, and dormancy break treatments are commonly employed in restoration, we also tested the effects of two pretreatments (cold stratification and gibberellic acid application) on time to germination. Seed traits, phylogeny, and seed pretreatments all affected time to germination. Of all traits tested, variables related to seed shape (height and shape variance) best predicted germination response, with high‐variance (i.e., pointier and narrower) seeds germinating faster. Phylogenetic position (the location of species on the phylogenetic tree relative to other tested species) was also an important predictor of germination response, that is, closely related species showed similar patterns in time to germination. This was true despite the fact that all measured seed traits showed phylogenetic signal, therefore phylogeny provided residual information that was not already captured by measured seed traits. Seed traits, phylogenetic position, and germination pretreatments were important predictors of germination response for a suite of species commonly used in grassland restoration. Shape traits were especially important, while mass, often the only seed trait used in studies of community assembly, was not a strong predictor of germination timing. These findings illustrate the ecological importance of seed traits that are rarely incorporated into functional studies of plant communities. This information can also be used to advance restoration practice by guiding restoration planning and seed mix design.