Plant ageing system indicator

Major equipment, stmcture, and other things to be managed under plant ageing system have been shown in Table I/6.2.3-1. This is an indicative list only, there can be others also, depending on plant type. 

Recent investigations indicate that the failure to obtain a positive chemotropic response may be an artifact. Failure to observe chemotropism may result from interference by pollen tube growth inhibitors, a factor causing negative chemotropism, by inherent errors in the surface test method, by the existence of genetically controlled incompatibility systems, and by factors of age of tissues and other characteristics of the plants. 

Mineral deficiency strongly affects the development of leaves and of the photosynthetic apparatus. We were interested to know whether carbon flux is more restricted in mineral deficient leaves by the thylakoid system or the Calvin cycle. Spinach was grown under mineral deficiency as shown in Tab. 1. Leaves of different age were detached and photosynthesis and F was measured. Rates of photosynthesis were on a unit leaf area basis consistently higher in the control leaves than in leaves deficient in phosphorus, sulfur or nitrogen. Sulfur and old nitrogen deficient leaves were chlorotic. F was increased under all deficiency conditions and particularly so in old leaves of phosphate and nitrogen starved plants and in young leaves of sulfur-deprived plants. The increase in F clearly correlated with the development of pronounced deficiency symptoms and reduced rates of photosynthesis. The data indicate that mineral deficiency introduces flux limitations in the Calvin cycle. 

Analysis of volatiles is frequently utilised in food industry to quality control food products and to determine shelf-life for various products. Some recent examples are the use of sensor arrays to differentiate milk products according to their aging times (12) and the use of solid phase microextraction-mass spectrometry-multivariate data system to predict the shelf-life of pasteurised milk (13). Volatiles emitted by plants have also been correlated to abiotic or biotic stress and the degree of damage caused by the stress (14). Similar principles should be applicable to polymeric materials i.e. the formation of certain volatiles or indicator products during degradation of the polymer is related to the changes in the polymer matrix (Fig. 1). 

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