Contents
 	Summary	30	
I.	Allocation in perspective	31	
II.	Topics of this review	32	
III.	Methodology	32	
IV.	Environmental effects	33	
V.	Ontogeny	36	
VI.	Differences between species	40	
VII.	Physiology and molecular regulation	41	
VIII.	Ecological aspects	42	
IX.	Perspectives	45	
 	Acknowledgements	45	
 	References	45	
 	Appendices A1–A4	49	


Summary
We quantified the biomass allocation patterns to leaves, stems and roots in vegetative plants, and how this is influenced by the growth environment, plant size, evolutionary history and competition. Dose–response curves of allocation were constructed by means of a meta-analysis from a wide array of experimental data. They show that the fraction of whole-plant mass represented by leaves (LMF) increases most strongly with nutrients and decreases most strongly with light. Correction for size-induced allocation patterns diminishes the LMF-response to light, but makes the effect of temperature on LMF more apparent. There is a clear phylogenetic effect on allocation, as eudicots invest relatively more than monocots in leaves, as do gymnosperms compared with woody angiosperms. Plants grown at high densities show a clear increase in the stem fraction. However, in most comparisons across species groups or environmental factors, the variation in LMF is smaller than the variation in one of the other components of the growth analysis equation: the leaf area : leaf mass ratio (SLA). In competitive situations, the stem mass fraction increases to a smaller extent than the specific stem length (stem length : stem mass). Thus, we conclude that plants generally are less able to adjust allocation than to alter organ morphology.

https://nph.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1469-8137.2011.03952.x

Biomass allocation to leaves, stems and roots: meta-analyses of interspecific variation and environmental control

The worldwide incidence of bone disorders and conditions has trended steeply upward and is expected to double by 2020, especially in populations where aging is coupled with increased obesity and poor physical activity. Engineered bone tissue has been viewed as a potential alternative to the conventional use of bone grafts, due to their limitless supply and no disease transmission. However, bone tissue engineering practices have not proceeded to clinical practice due to several limitations or challenges. Bone tissue engineering aims to induce new functional bone regeneration via the synergistic combination of biomaterials, cells, and factor therapy. In this review, we discuss the fundamentals of bone tissue engineering, highlighting the current state of this field. Further, we review the recent advances of biomaterial and cell-based research, as well as approaches used to enhance bone regeneration. Specifically, we discuss widely investigated biomaterial scaffolds, micro- and nano-structural properties of these scaffolds, and the incorporation of biomimetic properties and/or growth factors. In addition, we examine various cellular approaches, including the use of mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), adult stem cells, induced pluripotent stem cells (iPSCs), and platelet-rich plasma (PRP), and their clinical application strengths and limitations. We conclude by overviewing the challenges that face the bone tissue engineering field, such as the lack of sufficient vascularization at the defect site, and the research aimed at functional bone tissue engineering. These challenges will drive future research in the field.

/pdf/bone-tissue-engineering-recent-advances-and-challenges-4gc67py9d5.pdf

Bone Tissue Engineering: Recent Advances and Challenges

Bioceramics of calcium orthophosphates

Geneticists and breeders are positioned to breed plants with root traits that improve productivity under drought. However, a better understanding of root functional traits and how traits are related to whole plant strategies to increase crop productivity under different drought conditions is needed. Root traits associated with maintaining plant productivity under drought include small fine root diameters, long specific root length, and considerable root length density, especially at depths in soil with available water. In environments with late season water deficits, small xylem diameters in targeted seminal roots save soil water deep in the soil profile for use during crop maturation and result in improved yields. Capacity for deep root growth and large xylem diameters in deep roots may also improve root acquisition of water when ample water at depth is available. Xylem pit anatomy that makes xylem less "leaky" and prone to cavitation warrants further exploration holding promise that such traits may improve plant productivity in water-limited environments without negatively impacting yield under adequate water conditions. Rapid resumption of root growth following soil rewetting may improve plant productivity under episodic drought. Genetic control of many of these traits through breeding appears feasible. Several recent reviews have covered methods for screening root traits but an appreciation for the complexity of root systems (e.g., functional differences between fine and coarse roots) needs to be paired with these methods to successfully identify relevant traits for crop improvement. Screening of root traits at early stages in plant development can proxy traits at mature stages but verification is needed on a case by case basis that traits are linked to increased crop productivity under drought. Examples in lesquerella (Physaria) and rice (Oryza) show approaches to phenotyping of root traits and current understanding of root trait genetics for breeding.

/pdf/root-traits-contributing-to-plant-productivity-under-drought-3jg834tnub.pdf

Root traits contributing to plant productivity under drought.

The field of tissue engineering places complex demands on the materials it uses. The materials chosen to support the intricate processes of tissue development and maintenance need to have properties which serve both the bulk mechanical and structural requirements of the target tissue, as well as enabling interactions with cells at the molecular scale. In this critical review we explore how synthetic polymers can be utilised to meet the needs of tissue engineering applications, and how biomimetic principles can be applied to polymeric materials in order to enhance the biological response to scaffolding materials (105 references).

Synthetic polymer scaffolds for tissue engineering

Different materials were implanted in muscles of dogs to study the osteoinduction of calcium phosphate biomaterials. Bone formation was only seen in calcium phosphate biomaterials with micropores, and could be found in hydroxyapatite (HA) ceramic, tricalcium phosphate/hydroxyapatite ceramic (BCP), β-TCP ceramic and calcium phosphate cement. The osteoinductive potential was different in different materials. The results indicate that osteoinduction can be a property of calcium phosphate biomaterials when they exhibit specific chemical and structural characteristics. © 1998 Kluwer Academic Publishers

Osteoinduction by calcium phosphate biomaterials.

Temperature effect on transpiration response of maize plants to vapour pressure deficit

To investigate the relationship between bone morphogenetic proteins (BMP) and calcium phosphate ceramic-induced osteogenesis in soft tissues, in vitro and in vivo experiments were performed. In an in vitro study, the ability of different calcium phosphate ceramics to absorb bovine BMP (bBMP) from a bBMP solution was tested. In vivo studies included immunohistochemical BMP staining before bone formation in the ceramics was detected, and the enhancement of bone formation in calcium phosphate ceramics by bBMP. The results were: (1) calcium phosphate ceramics have a strong ability to absorb bBMP; (2) a high BMP concentration reaches inside the ceramic implants before bone formation in soft tissues of domestic pig occurs; (3) by 56% at 50 d and by 23% at 100 d, bBMP enhances bone formation in calcium phosphate ceramics implanted in soft tissues of dogs. The results indicate the BMP plays an important role in calcium phosphate ceramic-induced osteogenesis and that adsorption of native BMP from the body fluids to ceramic implants may be a key step in osteoinduction by calcium phosphate ceramics © 1998 Kluwer Academic Publishers

Bone morphogenetic protein and ceramic-induced osteogenesis

Kernel weight is an important factor determining grain yield and nutritional quality in sorghum, yet the developmental processes underlying the genotypic differences in potential kernel weight remain unclear. The aim of this study was to determine the stage in development at which genetic effects on potential kernel weight were realized, and to investigate the developmental mechanisms by which potential kernel weight is controlled in sorghum. Kernel development was studied in two field experiments with five genotypes known to differ in kernel weight at maturity. Pre-fertilization floret and ovary development was examined and post-fertilization kernel-filling characteristics were analysed. Large kernels had a higher rate of kernel filling and contained more endosperm cells and starch granules than normal-sized kernels. Genotypic differences in kernel development appeared before stamen primordia initiation in the developing florets, with sessile spikelets of large-seeded genotypes having larger floret apical meristems than normal-seeded genotypes. At anthesis, the ovaries for large-sized kernels were larger in volume, with more cells per layer and more vascular bundles in the ovary wall. Across experiments and genotypes, there was a significant positive correlation between kernel dry weight at maturity and ovary volume at anthesis. Genotypic effects on meristem size, ovary volume, and kernel weight were all consistent with additive genetic control, suggesting that they were causally related. The pre-fertilization genetic control of kernel weight probably operated through the developing pericarp, which is derived from the ovary wall and potentially constrains kernel expansion.

/pdf/pre-anthesis-ovary-development-determines-genotypic-1s9u8fc9so.pdf

Zongjian Yang

Papers

Osteoinduction by calcium phosphate biomaterials.

Temperature effect on transpiration response of maize plants to vapour pressure deficit

Bone morphogenetic protein and ceramic-induced osteogenesis

Pre-anthesis ovary development determines genotypic differences in potential kernel weight in sorghum

Modelling plant resource allocation and growth partitioning in response to environmental heterogeneity