1 Pisolithus.- 2 Suillus.- 3 Laccaria.- 4 Hebeloma.- 5 Rhizopogon.- 6 Tuber.- 7 Scleroderma.- 8 Amanita.- 9 Paxillus.- 10 Cantharellus.- 11 Lactarius.- 12 Cenococcum.- 13 Hysterangium.- 14 Thelephora.- 15 Resupinate Ectomycorrhizal Fungal Genera.

Ectomycorrhizal fungi : key genera in profile

Present evidence indicates that only the root systems of plants have been shown conclusively to synthesize cytokinins. Although most of these compounds are apparently exported to the shoot via the xylem, there are indications that more attention should be given to the possibility of translocation through the phloem. Within mature leaves the cytokinins derived from the roots are converted to inactive or storage forms by means of glucosylation. While it would appear that glucosylation could occur in all living plant cells whenever the cytokinins are no longer required for active growth, and could provide the plant with a potential reservoir of cytokinins, very little is known with regard to the transport and reutilisation of these compounds.

The synthesis, transport and metabolism of endogenous cytokinins

Biosynthesis and Metabolism of Plant Hormones

Publisher Summary Orchids are considered to have magical properties and medicinal values. The Orchidaceae is a vast family, with staggering 20,000–30,000 orchids, in specific with 600–800 genera and 25,000–35,000 species. In context to size, orchids range from the few millimeters and grams to several meters and tons. They are soft, delicate, and herbaceous or can be hard and nearly woody. Their pollination ranges from natural selfing to pseudocopulation in one and the same or different species. Fertilization does not immediately follow pollination in orchids and can occur in days, weeks, or even months after the flowers have been pollinated. The fruits develop slowly and can take a year or more to ripen. Carbon fixation patterns include C3, C4, and CAM. The chemical diversity and adaptive features of the orchids are enormous. They can be found in all climatic regions and most niches populated by flowering plants (except under water). The most surprising feature of orchids is that it can be compiled from studies of relatively few species by a limited number of investigators.

Aspects of the Physiology of Orchids

9 – Cytokinins and Senescence

When [8-14C]-N6-(Δ2-isopentenyl) adenosine is incubated with the endosperm of corn (2 weeks after pollination), it is converted to [14C]-N6-(4-hydroxy-3-methylbut-2-trans-enyl) adenosine, trans-ribosylzeatin. This biosynthetic step, N6-(Δ2-isopentenyl) adenosine to ribosylzeatin, also occurs in the mycorrhizal fungus, Rhizopogon roseolus.

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George Miura

Papers

trans-Ribosylzeatin Its Biosynthesis in Zea mays Endosperm and the Mycorrhizal Fungus, Rhizopogon roseolus