Structure and Function of Plant Roots

The 2nd International Symposium on Structure and Function of Roots or­ ganised by the Slovak Academy of Sciences was held in Bratislava in early September 1980 and continued the theme ofits 1971 predecessor at Tatranska Lomnica. The symposium started with 'structural characteristics of roots in relation to the process of growth'. The approach was notable for the way in which it brought together cytologists, electron microscopists and physiologists to discuss pro­ blems of common interest and set the scene for a muItidisciplinary approach to the remainder of the Symposium. Metabolie aspects of roots under normal conditions and after being exposed to stress received considerable attention, together with interesting contributions concerned with responses of roots to gravity. The session on water movement provided a useful balance between theoretical papers on the one hand and the resuIts ofthe use ofnew experimental approaches to the problem on the other. The Symposium continued with the examination of factors affecting the transport 01' ions into and across roots, particular attention focussing on metabolie aspects concerned with delivery ofions to the shoot. The problems associated with coordinating the separate functions 01' the root were introduced by a group ofpapers, again supported by contributions in which new experimental methods were described.

I. Growth processes, structural characteristics.- 1. Cellular organization of root growth.- 2. Growth region of the primary root of maize (Zea mays L.).- 3. Regulation of the mitotic cycle in seedling roots of Vicia faba by environmental factors.- 4. Maturing seed root growth and metabolism.- 5. Development of the mature root growth pattern in the course of seed germination.- 6. Structural and functional aspects of roots of germinating seeds.- 7. Cell proliferation during the development of lateral root primordia.- 8. Argyrophilic nuclear structures in root apices.- 9. Can induced autopolyploidy replace naturally occurring endopolyploidization in roots?.- 10. In situ 3H rRNA/DNA hybridization and silver staining of NORs during growth and differentiation of root cortex cells in the presence or absence of DNA endoreplication.- 11. Abnormalities in the ultrastructure of root cap cells in Raphanus sativus L. induced by actinomycin D, hydroxyurea, ?-naphthylacetic acid and streptomycin.- 12. DNA content in metaxylem of barley roots.- 13. A light microscopic study of the central metaxylem ontoge¬nesis in the root of barley (Hordeum distichum L.).- 14. Correlative morphogenesis of endodermis and xylem elements in the developing barley root.- 15. Division and differentiation during regeneration at the root apex.- 16. Root growth and gravireaetion. Endogenous hormone balance.- 17. ABA effects on root growth and gravireaction of Zea mays L..- 18. Critical study of the elongation and gravireaction of maize roots: light effect.- 19. The differentiation of rhizodermal cells in grasses.- 20. Distribution of plasmodesmata in root epidermis.- 21. Suberization and browning of grapevine roots.- II. Metabolism of roots.- 22. Regulation of enzymes involved in inorganic N metabolism in pea roots.- 23. The effect of manganese nutrition on nitrogen assimilation in roots.- 24. RNA synthesis in the root tip of maize.- 25. Development of protein patterns in the maize root stele.- 26. Glycosidases in the root tip.- 27. Glycosidase isoenzymes in root growth zones.- III. Transport phenomena.- A. Water transport.- 28. The movement of water across the plant root.- 29. Pressure-flow characteristics of the roots of Zea mays.- 30. On the nature of root pressure.- 31. Electroosmotic phenomena in longitudinal transport of solutes in roots.- 32. A possible driving force for the transport of water in roots: the temperature gradient.- 33. Conducting efficiency of roots for the longitudinal flow of water.- B. Ion uptake and transport.- 34. Mechanism of ion uptake across barley roots.- 35. Evidence for an ion uptake controller in Helianthus annuus.- 36. Efficiency of passive movement of ions in the root.- 37. Comparison of some membrane-bound ATPases of glycophytes and halophytes.- 38. Uptake and translocation of sodium in salt-sensitive and salt-tolerant Plantago species.- 39. The effect of CCCP on potassium uptake by root cells.- 40. Specialization of root tissues in ion transport.- 41. Sugar beet root as an organ for sucrose accumulation.- 42. Influence of IAA and ABA on compartmentation in red beet cells (Beta vulgaris L. ssp. vulgaris L. var. rubra).- 43. The effect of calcium on the accumulation and transport of sodium into different parts of barley roots.- 44. Permeability and conductance properties of the maize root epidermis.- 45. Absorption and transport of nutrient cations and anions in maize roots.- 46. Absorption and transport of anions by different roots of Zea mays L..- 47. Metabolic aspects of the transport of ions by cells and tissues of roots.- 48. Accumulation of cations and the functional activity of mitochondria from roots.- 49. Absorption and transport of sulphate in relation to its metabolism.- 50. The effect of phenolic acids on metabolism and nutrient uptake of roots.- 51. Effects of endomyeorrhizal infection on phosphate and cation uptake by Trifolium subterraneum.- IV. Functional integrity of the root system.- 52. Co-ordination of growth phenomena within a root system of intact maize plants.- 53. Relation between root respiration and root activity.- 54. The efficiency of root respiration in different environments.- 55. The influence of mechanical resistance and phosphate supply on morphology and function of corn roots.- 56. Genetical variability of the size of the lucerne root system determined by its electrical capacity.- 57. Genetical variation in efficiency of plant root systems.- V. Responses of roots to stress.- 58. Structure and function in absorption and transport of nutrients.- 59. Some aspects of structural and functional modifications induced by drought in root systems.- 60. Ultrastructure of maize root cells under water stress conditions.- 61. The effect of flooding on metabolism and structure of maize roots.- 62. The response of Zea mays roots to chilling.- 63. The study of root growth under low temperatures at the cell level.- 64. Nitrogen assimilation in wheat in relation to the root zone temperature.- 65. Effect of aluminium toxicity on root morphology of barley.- 66. Effect of heavy metals and chelating agents on potassium uptake of cereal roots.- 67. Transport and metabolism of sulphate under salt stress.- VI. Interaction between roots and shoots.- 68. Shoot: root functional equilibria — thermodynamic stability of the plant system.- 69. Root-shoot relationships in mature grass plants.- 70. Inter-organ control of photosynthesis mediated by emerging nodal roots in young maize plants.- 71. Root-shoot interactions in fruiting tomato plants.- 72. Function of roots in NaCl-stressed bean plants.- 73. The distribution of 14C-photoassimilates in wheat seedlings under root anaerobiosis and DNP application to the roots.- 74. Influence of nitrate and aeration on growth and chemical composition of Zea mays L..- 75. Relationship between the root and above ground parts of different sunflower inbreds regarding the content of some mineral elements.- 76. Response of barley roots to infection by the parasitic fungus Erysiphe graminis DC.- 77. Translocation of growth regulators from roots in relation to the stem apical dominance in pea (Pisum sativum L.) seedlings.