No abstract

We present a method for estimating the construction costs of plant tissues from measurements of heat of combustion, ash content, and organic nitrogen eontent. The method prediets glucose equivalents, the amount of glucose required to provide earbon skeletons and r-eduetant to synthesize a quantity of organic produet. Glueose equivalents have previously been ealculated frorn the elemental eomposition of tissue. We define construetion cost as the amount of glueose requir-ed to provide carbon skeletons, reduetant and ATP for synthesizing the organie eompounds in a tissue via standard biochemieal pathways. The fraetion of the total construetion eost of a eompound or tissue (excluding costs of transporting eompounds) that is reflected in its glueose equivalents is the biosynthetie efficieney (£"). This quantity varies between 0.84 and 0.95 for tissues with a wide range of compositions. Using the new method, total eonstruetion cost ean be estimated to +6% of the value obtained from bioehemical pathway analysis.Construction costs of leaves ot" three ehaparral species -were estimated using the proposed method and compared to previously published values, derived using different methods. Agreement among methods was generally good. Differenees were probably due to a eornbination of inaeeuracy in the estimated biosynthetie efficiency and teehnieal difficulties with bioehernieal analysis, one of the older methods of determining construction cost.

We present a method for estimating the construction costs of plant tissues from measurements of heat of combustion, ash content, and organic nitrogen eontent. The method prediets glucose equivalents, the amount of glucose required to provide earbon skeletons and r-eduetant to synthesize a quantity of organic produet. Glueose equivalents have previously been ealculated frorn the elemental eomposition of tissue. We define construetion cost as the amount of glueose requir-ed to provide carbon skeletons, reduetant and ATP for synthesizing the organie eompounds in a tissue via standard biochemieal pathways. The fraetion of the total construetion eost of a eompound or tissue (excluding costs of transporting eompounds) that is reflected in its glueose equivalents is the biosynthetie efficieney (£"). This quantity varies between 0.84 and 0.95 for tissues with a wide range of compositions. Using the new method, total eonstruetion cost ean be estimated to +6% of the value obtained from bioehemical pathway analysis.Construction costs of leaves ot" three ehaparral species -were estimated using the proposed method and compared to previously published values, derived using different methods. Agreement among methods was generally good. Differenees were probably due to a eornbination of inaeeuracy in the estimated biosynthetie efficiency and teehnieal difficulties with bioehernieal analysis, one of the older methods of determining construction cost.