Crop rotation was practiced in ancient times by alternating the use of leguminous and nonleguminous plants. The basis for the benefit derived from this practice was not understood, but it was observed empirically that crops were improved and the condition of the soil was maintained better with rotation than by continual cropping with nonleguminous plants. Rotation was recognized as good husband...

The control exerted by light on leaf and stem growth in light-grown Alaska pea seedlings was studied during the main photoperiod. Two high irradiance responses were observed. The action spectrum for one had a single sharp peak at 600 nanometers. The action spectrum for the other showed a broad peak between 440 and 470 nanometers. These two light responses must be activated simultaneously for an...

Activity of indoleacetic acid oxidase was shown to increase following a period of water stress. Two fractions of indoleacetic acid oxidase were extracted from plant extracts. Similarly, two protein peaks (determined by ultraviolet absorption) were isolated. One peak, associated with an indoleacetic acid oxidase peak, increased following water stress. The second peak, not associated with extract...

Flavonoicl synthesis is, in many plants, either promloted by light or (lepen(lent upoIn light (3). The nature of this light re(quirement appears to vary depending UpOnl the conmpounds ancl plant miiaterials being studiedl ( 15, 17, 19, 21, 23 ), and little is known regalrding the relationship between photoinduced sy-nthesis of these compounds and photoincluced growth an(l (levelopmlenit. In eti...

Auxin treatment of aged pea stems (Pisum sativum L. var. Alaska) caused a decrease in monosomes (especially free monosomes) and an increase in polysomes (especially membrane-bound polysomes). These effects were not duplicated by gibberellic acid or benzyladenine. These auxin-stimulated shifts in polysome distribution commenced at least 9 hours before significant growth took place. It is suggest...