With the completion of the Arabidopsis genome sequencing project, the next major challenge is the large-scale determination of gene function. As a model organism for agricultural biotechnology, Arabidopsis presents the opportunity to provide key insights into the way that gene function can affect commercial crop production. In an attempt to aid in the rapid discovery of gene function, we have established a high throughput phenotypic analysis process based on a series of defined growth stages that serve both as developmental landmarks and as triggers for the collection of morphological data. The data collection process has been divided into two complementary platforms to ensure the capture of detailed data describing Arabidopsis growth and development over the entire life of the plant. The first platform characterizes early seedling growth on vertical plates for a period of 2 weeks. The second platform consists of an extensive set of measurements from plants grown on soil for a period of approximately 2 months. When combined with parallel processes for metabolic and gene expression profiling, these platforms constitute a core technology in the high throughput determination of gene function. We present here analyses of the development of wild-type Columbia (Col-0) plants and selected mutants to illustrate a framework methodology that can be used to identify and interpret phenotypic differences in plants resulting from genetic variation and/or environmental stress.

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Growth Stage –Based Phenotypic Analysis of Arabidopsis: A Model for High Throughput Functional Genomics in Plants

Reflectance measurement of canopy biomass and nitrogen status in wheat crops using normalized difference vegetation indices and partial least squares regression

The large area of rice (Oryza sativa L) production worldwide is critical to the well being of large numbers of the world's people Yet for rice, the most important single plant species for human nutrition, there is not a widely used growth staging system Despite good points of the published rice growth staging systems, none has been used widely for describing rice growth and development Consequently, an objective growth staging system with enumeration adapted to cumulative leaf number (CLN) would improve communication among scientists, farmers, and educators We propose a rice developmental staging system divided into three main phases of development: seedling, vegetative, and reproductive Seedling development consists of four growth stages: unimbibed seed (S0), radicle and coleoptile emergence from the seed (S1,S2), and prophyll emergence from the coleoptile (S3) Vegetative development consists of stages V1, V2 VN; N being equal to the final number of leaves with collars on the main stem Reproductive development consists of 10 growth stages based on discrete morphological criteria: panicle initiation (R0), panicle differentiation (R1), flag leaf collar formation (R2), panicle exertion (R3), anthesis (R4), grain length and width expansion (R5), grain depth expansion (R6), grain dry down (R7), single grain maturity (R8), and complete panicle maturity (R9) Assigning rice growth stages based on discrete morphological criteria will result in unambiguous growth-stage determination For example, using this system, two people staging the same plant will arrive at the same growth stage This is because the system exploits the presence or absence of distinct morphological criteria in a symbolic logic dichotomous framework that only permits yes or no answers

A Uniform, Objective, and Adaptive System for Expressing Rice Development

Combining UAV-based plant height from crop surface models, visible, and near infrared vegetation indices for biomass monitoring in barley

In mammals, cadmium is widely considered as a non-genotoxic carcinogen acting through a methylation-dependent epigenetic mechanism. Here, the effects of Cd treatment on the DNA methylation patten are examined together with its effect on chromatin reconfiguration in Posidonia oceanica. DNA methylation level and pattern were analysed in actively growing organs, under short- (6 h) and long- (2 d or 4 d) term and low (10 mM) and high (50 mM) doses of Cd, through a Methylation-Sensitive Amplification Polymorphism technique and an immunocytological approach, respectively. The expression of one member of the CHROMOMETHYLASE (CMT) family, a DNA methyltransferase, was also assessed by qRT-PCR. Nuclear chromatin ultrastructure was investigated by transmission electron microscopy. Cd treatment induced a DNA hypermethylation, as well as an up-regulation of CMT, indicating that de novo methylation did indeed occur. Moreover, a high dose of Cd led to a progressive heterochromatinization of interphase nuclei and apoptotic figures were also observed after long-term treatment. The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase. Such changes are linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin. Overall, the data show an epigenetic basis to the mechanism underlying Cd toxicity in plants.

/pdf/in-posidonia-oceanica-cadmium-induces-changes-in-dna-3cu7uj83mr.pdf

In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning

Summary
A universal scale (to be known as the BBCH scale) using a decimal code for the description of the growth stages of most agricultural crops and weeds is proposed. The scale and codes are based on the well-known Zadoks code for cereals.

Developmentally similar growth stages of different crops are given the same codes. The general scale provides a framework within which more specific scales for individual crops may be constructed. The uniformity of the scale makes it easy to remember and use in agricultural practice and simplifies storage and retrieval in a computer system.

A description of the general scale is given followed by specific scales for cereals, rice, maize, oilseed rape, field beans, peas and sunflower. Comparisons with scales currently in use are given where appropriate.

A. Witzenberger

Papers

A uniform decimal code for growth stages of crops and weeds

A new uniform decimal code for growth stages of crops and weeds