The growth of vegetative and reproductive structures (leaves and silks) respond similarly to hydraulic cues in maize.

The elongation of styles and stigma (silks) of maize (Zea mays) flowers is rapid (1-3 mm h(-1) ), occurs over a short period and plays a pivotal role in reproductive success in adverse environments. Silk elongation rate was measured using displacement transducers in 350 plants of eight genotypes during eight experiments with varying evaporative demand and soil water status. Measured time courses revealed that silk elongation rate closely followed changes in soil water status and evaporative demand, with day-night alternations similar to those in leaves. Day-night alternations were steeper with high than with low plant transpiration rate, manipulated via evaporative demand or by covering part of the leaf area. Half times of changes in silk elongation rate upon changes in evaporative demand or soil water status were 10-30 min, similar to those in leaves. The sensitivity of silk elongation rate to xylem water potential was genetically linked to that of leaf elongation rate. Lines greatly differed for these sensitivities. These results are consistent with a common hydraulic control of expansive growth in vegetative and reproductive structures upon changes in environmental conditions via a close connection with the xylem water potential. They have important implications for breeding, modelling and phenotyping.

[1]  F. Tardieu,et al.  Control of Leaf Expansion Rate of Droughted Maize Plants under Fluctuating Evaporative Demand (A Superposition of Hydraulic and Chemical Messages?) , 1997, Plant physiology.

[2]  Y. Gibon,et al.  Water deficits uncouple growth from photosynthesis, increase C content, and modify the relationships between C and growth in sink organs. , 2011, Journal of experimental botany.

[3]  François Tardieu,et al.  Aquaporin-Mediated Reduction in Maize Root Hydraulic Conductivity Impacts Cell Turgor and Leaf Elongation Even without Changing Transpiration1[W] , 2009, Plant Physiology.

[4]  R. R. Johnson,et al.  Drought Stress and Its Effects on Maize Reproductive Systems1 , 1981 .

[5]  Christian Körner,et al.  Moving beyond photosynthesis: from carbon source to sink-driven vegetation modeling. , 2014, The New phytologist.

[6]  François Tardieu,et al.  Water deficit and growth. Co-ordinating processes without an orchestrator? , 2011, Current opinion in plant biology.

[7]  François Tardieu,et al.  Dealing with the genotype x environment interaction via a modelling approach: a comparison of QTLs of maize leaf length or width with QTLs of model parameters. , 2004, Journal of experimental botany.

[8]  Francois Tardieu,et al.  Leaf growth rate per unit thermal time follows QTL-dependent daily patterns in hundreds of maize lines under naturally fluctuating conditions. , 2007, Plant, cell & environment.

[9]  F. Tardieu,et al.  Drought and Abscisic Acid Effects on Aquaporin Content Translate into Changes in Hydraulic Conductivity and Leaf Growth Rate: A Trans-Scale Approach1[W][OA] , 2009, Plant Physiology.

[10]  François Chaumont,et al.  A Hydraulic Model Is Compatible with Rapid Changes in Leaf Elongation under Fluctuating Evaporative Demand and Soil Water Status1[C][W][OPEN] , 2014, Plant Physiology.

[11]  Valeriy Y. Ivanov,et al.  Modeling plant–water interactions: an ecohydrological overview from the cell to the global scale , 2016 .

[12]  D. Hoisington,et al.  Identification of quantitative trait loci under drought conditions in tropical maize. 2. Yield components and marker-assisted selection strategies , 1997, Theoretical and Applied Genetics.

[13]  P. Chourey,et al.  The Maize Invertase-Deficient miniature-1 Seed Mutation Is Associated with Aberrant Pedicel and Endosperm Development. , 1992, The Plant cell.

[14]  T. Setter,et al.  Comparative Transcriptional Profiling of Placenta and Endosperm in Developing Maize Kernels in Response to Water Deficit1 , 2003, Plant Physiology.

[15]  F. Tardieu,et al.  Spatial distributions of expansion rate, cell division rate and cell size in maize leaves: a synthesis of the effects of soil water status, evaporative demand and temperature. , 2000, Journal of experimental botany.

[16]  J. Shannon,et al.  Movement of C-labeled Assimilates into Kernels of Zea mays L: III. AN ANATOMICAL EXAMINATION AND MICROAUTORADIOGRAPHIC STUDY OF ASSIMILATE TRANSFER. , 1980, Plant physiology.

[17]  J. Lockhart.  An analysis of irreversible plant cell elongation. , 1965, Journal of theoretical biology.

[18]  R. Loomis,et al.  Nitrogen and density influences on silk emergence, endosperm development, and grain yield in maize (Zea mays L.) , 1994 .

[19]  F. Tardieu,et al.  Genetic and Physiological Controls of Growth under Water Deficit1 , 2014, Plant Physiology.

[20]  F. Tardieu,et al.  A Common Genetic Determinism for Sensitivities to Soil Water Deficit and Evaporative Demand: Meta-Analysis of Quantitative Trait Loci and Introgression Lines of Maize1[W][OA] , 2011, Plant Physiology.

[21]  J. Heslop-Harrison,et al.  THE POLLEN‐STIGMA INTERACTION IN THE GRASSES. 5. TISSUE ORGANISATION AND CYTOCHEMISTRY OF THE STIGMA (“SILK”) OF ZEA MAYS L. , 1984 .

[22]  W. Bruening,et al.  Fruit development and reproductive survival in soybean: Position and age effects , 2006 .

[23]  F. Tardieu,et al.  Control of leaf growth by abscisic acid: hydraulic or non-hydraulic processes? , 2010, Plant, cell & environment.

[24]  F. Tardieu,et al.  Are source and sink strengths genetically linked in maize plants subjected to water deficit? A QTL study of the responses of leaf growth and of Anthesis-Silking Interval to water deficit. , 2006, Journal of experimental botany.

[25]  P. Weatherwax.  Morphology of the Flowers of Zea mays , 1916 .

[26]  D. Susko.  Effect of ovule position on patterns of seed maturation and abortion in Robinia pseudoacacia (Fabaceae) , 2006 .

[27]  Alain Charcosset,et al.  Combining Quantitative Trait Loci Analysis and an Ecophysiological Model to Analyze the Genetic Variability of the Responses of Maize Leaf Growth to Temperature and Water Deficit1 , 2003, Plant Physiology.

[28]  M. Stitt,et al.  Modelling temperature-compensated physiological rates, based on the co-ordination of responses to temperature of developmental processes. , 2010, Journal of experimental botany.

[29]  Roland Chapuis,et al.  Resiliences to water deficit in a phenotyping platform and in the field: How related are they in maize? , 2012 .

[30]  G. Edmeades,et al.  Molecular and physiological approaches to maize improvement for drought tolerance. , 2002, Journal of experimental botany.

[31]  Christoforos Pappas,et al.  Modeling terrestrial carbon and water dynamics across climatic gradients: does plant trait diversity matter? , 2016, The New phytologist.

[32]  F. Tardieu,et al.  Modelling the coordination of the controls of stomatal aperture, transpiration, leaf growth, and abscisic acid: update and extension of the Tardieu-Davies model. , 2015, Journal of Experimental Botany.

[33]  J. Boyer,et al.  Leaf enlargement and metabolic rates in corn, soybean, and sunflower at various leaf water potentials. , 1970, Plant physiology.

[34]  O. Turc,et al.  Phenological response of pea to water stress during reproductive development , 1994 .

[35]  M. Westgate,et al.  Plant factors controlling seed set in maize : the influence of silk, pollen, and ear-leaf water status and tassel heat treatment at pollination. , 1987, Plant physiology.

[36]  Y. Gibon,et al.  Is Change in Ovary Carbon Status a Cause or a Consequence of Maize Ovary Abortion in Water Deficit during Flowering?1[OPEN] , 2016, Plant Physiology.

[37]  D. Johnson,et al.  Characterization of a novel glycine-rich protein from the cell wall of maize silk tissues , 2006, Plant Cell Reports.

[38]  François Tardieu,et al.  Ovary Apical Abortion under Water Deficit Is Caused by Changes in Sequential Development of Ovaries and in Silk Growth Rate in Maize1[OPEN] , 2015, Plant Physiology.

[39]  D. Hoisington,et al.  Identification of quantitative trait loci under drought conditions in tropical maize. 1. Flowering parameters and the anthesis-silking interval , 1996, Theoretical and Applied Genetics.

[40]  Wei Zhang,et al.  Genome-wide identification and characterization of maize expansin genes expressed in endosperm , 2014, Molecular Genetics and Genomics.

[41]  D. Cosgrove.  Growth of the plant cell wall , 2005, Nature Reviews Molecular Cell Biology.

[42]  Mark E. Westgate,et al.  Emergence, Elongation, and Senescence of Maize Silks , 1993 .

[43]  François Tardieu,et al.  Drought-induced changes in anthesis-silking interval are related to silk expansion: a spatio-temporal growth analysis in maize plants subjected to soil water deficit. , 2008, Plant, cell & environment.

[44]  S. Lutts,et al.  Resource availability regulates reproductive meristem activity, development of reproductive structures and seed set in buckwheat (Fagopyrum esculentum). , 2007, Physiologia plantarum.

[45]  F. Tardieu,et al.  The growths of leaves, shoots, roots and reproductive organs partly share their genetic control in maize plants. , 2013, Plant, cell & environment.

[46]  M. Westgate,et al.  Osmotic adjustment and the inhibition of leaf, root, stem and silk growth at low water potentials in maize , 1985, Planta.

[47]  A. Stephenson,et al.  Order of fertilization within the ovary in Phaseolus coccineus L. (Leguminosae) , 1991, Sexual Plant Reproduction.

[48]  R. Shibles,et al.  Pollination Timing Effects on Kernel Set and Silk Receptivity in Four Maize Hybrids , 2004 .