Knowledge concerning the enzymic systems of various pathogenic bacteria and their dependence on specific vitamins or accessory substances is still rather vague. The work of Davis (1917), Thj6tta and Avery (1921), and Fildes (1921) has demonstrated that Hemophilus influenzae requires two substances for its growth: x, a heat-stable substance, probably hematin, and v, a heat-labile substance. Klig...

A method for estimating inhibition of pollen tube growth was developed. Pollen is placed in straight lines on an agar surface where it responds uniformly and predictably to aqueous solutions of germination-inhibiting substances located in wells at the ends of the lines. A scale of ratings, roughly corresponding to serial, doubled concentrations of inhibiting substances, was devised. Water-solub...

Lanolin is frequently used as a diluent for applying growth substances 'to plants. Its earliest use was described by LAIBACH (1). He applied unilaterally, to the first internodes of Phaseolus multiflorus seedlings, a lanolin paste containing the test substance. The presence of growth substances induced negative stem curvatures. Subsequently, Laibach and co-workers (2, 3) applied lanolin pastes ...

humic substances as an active part of soil organic maters can improve germination and seedling properties, plant establishment and plant growth. in order to study the effects of different concentrations of humic and fulvic acids on germination and seedling properties of two varieties of triticale (triticosecale hexaploide lart.), a factorial experiment based on a completely randomized design wi...

Cellular senescence is characterized by cellular hypertrophy: cell growth in the absence of cell division. The genes that regulate this process can be activated or inactivated by numerous plant polyphenols such as resveratrol, quercetin, butein, fistein, piceatannol, curcumin. Many of these substances have been shown to lengthen the lifespan of invertebrates. Many of these compounds have other ...