Lattice strain and tilt mapping in stressed Ge microstructures using X-ray Laue micro-diffraction and rainbow-filtering

Micro-Laue diffraction and simultaneous rainbow-filtered micro-diffraction were used to measure accurately the full strain tensor and the lattice orientation distribution at the sub-micron scale in highly strained, suspended Ge micro-devices. A numerical approach to obtain the full strain tensor from the deviatoric strain measurement alone is also demonstrated and used for faster full strain mapping. We performed the measurements in a series of micro-devices under either uniaxial or biaxial stress and found an excellent agreement with numerical simulations. This shows the superior potential of Laue micro-diffraction for the investigation of highly strained micro-devices.Comment: 28 pages, 10 figure

Use of maize haploid inducer line to decipher plant reproduction

International audienc

Communications et échanges au sein du grain de maïs

National audienc

Haploid Embryos: Being Like Mommy or Like Daddy?

International audienceIn planta haploid embryo induction is a powerful plant breeding tool, but is limited to very few crops. Two recent studies by Wang et al. and Lv et al. report seed-based haploid systems that produce paternal haploid embryos by engineering CENTROMERIC HISTONE H3 (CENH3). Together with recent translation of maize maternal haploid induction ability into wheat and rice, this extends our collection of haploid inducer lines

Absent daddy, but important father

International audienceMixing maternal and paternal genomes is the base of plant sexual reproduction, but some so-called 'haploid inducer lines' lead to the formation of seeds bearing well-developed embryos with solely the maternal genome. A recent study adds a new piece to the puzzle of this enigmatic in planta haploid embryo induction process

Overview of In Vitro and In Vivo Doubled Haploid Technologies

International audienceDoubled haploids (DH) have become a powerful tool to assist in different basic research studies, and also in applied research. The principal (but not the only) and routine use of DH by breeding companies is to produce pure lines for hybrid seed production in different crop species. Several decades after the discovery of haploid inducer lines in maize and of anther culture as a method to produce haploid plants from pollen precursors, the biotechnological revolution of the last decades allowed to the development of a variety of approaches to pursue the goal of doubled haploid production. Now, it is possible to produce haploids and DHs in many different species, because when a method does not work properly, there are several others to test. In this chapter, we overview the currently available approaches used to produce haploids and DHs by using methods based on in vitro culture, or involving the in vivo induction of haploid embryo development, or a combination of both

Embryo-endosperm-sporophyte interactions in maize seeds

Maize seeds, like those of all other angiosperms, are highly complex biological systems. This complexity is a consequence of the fact that the angiosperm seed is composed of tissues that evolved from three genetically distinct organisms: the mother plant (maternal sporophyte-specifically the nucellus, integuments, and in the case of maize and other cereals, other floral organs that fuse with the integuments to form the pericarp); the developing embryo (zygotic sporophyte); and the endosperm (arising through fertilization-dependent proliferation of a second fertilization competent cell of the female gametophyte). In evolutionary terms, the two main interactions that will be addressed in this chapter initially arose well before emergence of the angiosperms. The first and probably most ancient association is "retention and nourishment" of the sporophytic embryo by the female gametophyte. The second association is derived from the "retention of the megaspore" by the maternal sporophyte, and the subsequent extended interaction of maternal tissues (the nucellus and integuments) with the developing female gametophyte (and subsequently, in angiosperms, the endosperm). This chapter addresses interactions that occur at compartment interfaces. After a short description of their structures, it focuses mainly on three aspects: (i) the potential role of signalling peptides (and other mobile substances) and their receptors as signalling components in cell fate decisions and intercompartmental communication; (ii) the role of sugars both as nutrients and as signalling molecules; and (iii) the role and control of cell death processes as a consequence of physical interactions and as a potential source of signalling molecules for intercompartmental communication