The transformation of normal plant tissue into tumor tissue occurs in three steps, which have been designated conditioning, induction, and promotion.' Conditioning is accomplished by substances present in the wound juice; induction by a tumorinducing principle (T-iP) produced by virulent Agrobacterium tumefaciens grown in unheated plant juice; and promotion, by indoleacetic acid or its physiolo...

Jasmonic acid (JA) and methyl jasm onate (JA-Me, 1) are naturally occurring substances in plants. They are representatives of a group of plant growth regulators [1], The exact quantifica­ tion of JA in plant materials is of great interest for further studies on transport, metabolism and en­ dogenous importance of JA. Using the GC/M SSIM method deuterium-labelled JA should be a good internal sta...

Insect antifeeding substances contained in plant leaves were widely surveyed by monitoring with 'leaf-disc test'. Larvae of tobacco cutworm, Spodoptera litura F., were mainly the test insects and leaves of sweet potato, Ipomoea batatas Lamark var. edulis Makino, the insect baits. Leaves of Cocculus trilobus DC, Parabenzoin trilobum Nakai (= Lindera triloba Blume), Orixa japonica Thunberg, Clero...

Earthworms (Eisenia foetida) produce humic substances that can influence plant growth by mechanisms that are not yet clear. In this work, we investigated the effects of humic acids (HAs) isolated from cattle manure earthworm compost on the earliest stages of lateral root development and on the plasma membrane H(+)-ATPase activity. These HAs enhance the root growth of maize (Zea mays) seedlings ...

The production of antifungal substances by bacteria has long been recognized and this knowledge is entering practical life through the use of bacterial antagonists to protect crops against their fungal enemies. Recently, it has become clear that in addition to diffusible substances, bacteria emit a wide range of volatile compounds into the atmosphere. Over the last ten years, evidence has accum...

WHEN a piece of a stem is cut out from a plant one or more new shoots will usually arise at the apical, and roots at the basal end of the piece. This phenomenon of axial polarity was explained by the older botanists as being due to a flow of shoot-forming substances to the apex and of root-forming sulbstances to the base. The gathering of these substances at opposite ends of the piece was belie...