During the past decade ecologist have devoted considerable energy to demographic studies of flowers and fruits between anthesis and dispersal. These efforts have led to the growing realization that the number of flowers and fruits and the way they are clustered in time and space influence pollinator attraction...

Flower and Fruit Abortion: Proximate Causes and Ultimate Functions

Optimal leaf size in relation to environment

Climate changes and trends in phenology and yields of field crops in China, 1981-2000

It was once proposed that there are only two kinds of biology: elegant genetics and sloppy biochemistry (E.C. Pauling, unpublished). For those who study auxin metabolism in Arabidopsis, this geneticist’s view of the different approaches to biological research has particular resonance. Arabidopsis has the advantage of providing a model molecular genetic system in a plant that uses the indole ring to produce diverse compounds, such as the glucosinolate glucobrassicin, the phytoalexin camalexin and the phytohormone indole-3-acetic acid (IAA). This model plant genetic system offers unique opportunities to apply new approaches to answer long-standing questions regarding auxin. However, studies in Arabidopsis can often present us with confounding problems when it comes to careful dissection of the network of indolic pathways in either normal or mutant plants. In this review, we focus our attention on IAA metabolism in Arabidopsis, However, by necessity we have been obliged to draw complementary information from the literature on other species to delineate as completely as possible the most current views on processes responsible for IAA production and its regulation.

Biosynthesis, conjugation, catabolism and homeostasis of indole-3-acetic acid in Arabidopsis thaliana.

. Despite intensive research effort, the role of growth substances in the life of the intact growing plant is far from clear. Two reasons are suggested which may account for the lack of progress. The first is the failure to recognize the unique aspects of plant development. These which are expressed by the regenerative, organizational and developmental plasticity of the meristem probably result from the possession of growth substances. The second is the concept of growth substances as hormones. This represents the main conceptual thrust of research and is considered critically, starting with the historical system, the coleoptile and dealing with other major growth substance systems in turn. It is concluded that a hormonal concept which includes control by changes in growth substance concentration fails to explain the developmental phenomena under examination. A role for growth substances as integrating agents is suggested and the notion of quantitative tissue sensitivity variation is developed to explain the major growth patterns of developing shoots.

How do plant growth substances work? II

Plant growth and development , Plant growth and development , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

A. Carl Leopold

Papers

Plant Growth and Development