Physiological integration of parents and ramets of Agave deserti: Carbon relations during vegetative and sexually reproductive growth

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5673872

Tissue, D T

Agave deserti is a semelparous perennial occurring in the northwestern Sonoran Desert that flowers after 50-55 years, but propagates primarily vegetatively by ramets. Shading ramets in the field to light compensation for two years did not decrease their relative growth rate compared with unshaded ramets. However, parents experienced a 30% decrease in total nonstructural carbohydrate (TNC) level, indicating that carbohydrates were translocated from parents to ramets. Parents were also shaded in the field for two years and about 10% of the growth of the shaded parents was attributed to TNC received from their attached, unshaded ramets indicating bidirectional translocation of carbohydrates between parents and ramets. The amount of carbon imported by a ramet from its parent, measured using {sup 14}CO{sub 2} techniques, was related to its photosynthetically active radiation environment, shaded ramets received 2.1 times more carbon than unshaded ramets, and was inversely related to the mass of the ramet, small ramets received up to 4.5 times more carbon than large ramets. The physiological integration of parents and ramets allows ramets to draw upon the reserves of the parent, thereby facilitating ramet growth and establishment in a resource-limited environment. Rosettes of Agave deserti must attain a minimum size (> 1,000 g dry mass) to initiate flowering, unless they are connected to a large flowering parent. Ramets that flower precociously can not complete formation of their inflorescence unless partially supported by carbon supplied by their attached parent. TNC reserves of the parent provided 70% of the carbon required to produce its own inflorescence, typically 4 m tall and 1.5 kg in dry mass, and CO{sub 2} uptake by the leaves and the inflorescence provided the remaining 30%.

• Research Organization: California Univ., Los Angeles, CA (United States)
• OSTI ID: 5673872
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ARID LANDS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
GROWTH
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANT GROWTH
PLANTS
PROGENY
SYNTHESIS
TRACER TECHNIQUES
TRANSLOCATION