Temperature stress during kernel development affects maize (Zea mays 1.) grain growth and yield stability. Maize kernels (hybrid A619 x W64A) were cultured in vitro at 3 d after pollination and either maintained at 25°C or transferred to 35'C for 4 or 8 d, then returned to 25'C until physiological maturity. Kernel fresh and dry matter accumulation was severely disrupted by the long-term heat st...

Cytokinin flow from roots to shoots can serve as a long-distance signal important for root-to-shoot communication. In the past, changes in cytokinin flow from roots to shoots have been mainly attributed to changes in the rate of synthesis or breakdown in the roots. The present research tested the possibility that active uptake of cytokinin by root cells may also influence its export to shoots. ...

A cytokinin-binding protein has been isolated from wheat germ via ammonium sulfate precipitation, carboxymethyl Sephadex chromatography, and affinity chromatography on a column substituted with a derivative of kinetin riboside. On Sephadex G-200, the protein migrated with an apparent molecular weight of 122,000 daltons. The dissociation constant for kinetin was determined by equilibrium dialysi...

Three cytokinin-active constituents have been isolated from the culture medium of Corynebacterium fascians, a plant pathogen causing fasciation. One constituent is now identified as cis-zeatin [6-(4-hydroxy-3-methyl-cis-2-butenylamino)purine]. It represents the first unequivocal demonstration of the production of a zeatin isomer by a bacterial species. Another constituent was identified earlier...

Until now numbers of efforts have been made to deduce the optimized conditions for the in vitro regeneration of tomato plant. The optimized conditions deduced are contradictory to each other and to validate the optimum conditions the present investigation was carried out which directs the use of 1.5 mg/l IAA + 1.5 mg/l Zeatin with full strength Murashige and Skoog’s (MS) medium for the developm...

Cytokinin-like activity in samples of xylem and phloem sap collected from field-grown plants of white lupin (Lupinus albus L.) over a period of 9 to 24 weeks after sowing was measured using the soybean hypocotyl callus bioassay following paper chromatographic separation. The phloem sap was collected from shallow incisions made at the base of the stem, the base of the inflorescence (e.g. stem to...

Class 1 KNOTTED-like (KNOX) transcription factors control cell meristematic identity. An investigation was carried out to determine whether they maintain this function in peach plants and might act in leaf curliness caused by the ascomycete Taphrina deformans. KNOPE1 function was assessed by overexpression in Arabidopsis and by yeast two-hybrid assays with Arabidopsis BELL proteins. Subsequentl...

Ultra-performance liquid chromatography-tandem mass spectrometry was used to establish the cytokinin profile of the bryophyte Physcomitrella patens (Hedw.) B.S.G.; of 40 analyzed cytokinins, 20 were detected. cis-Zeatin-riboside-O-glucoside, N(6)-(Delta(2)-isopentenyl)adenosine-5'-monophosphate (iPRMP), and trans-zeatin-riboside-O-glucoside were the most abundant intracellular cytokinins. In ad...