The Law Of Material And Energy Metabolism Regulated By The Key Enzyme Of Respiration In The Process Of Seed Germination

Since Kleiber proposed 3/4 law, many scholars have devoted to study on the allometric relationship of organism on all levels. WBE model holds that the allometric exponent between metabolic rate and body mass of plant is 3/4. However, Metabolic Theory of Ecology(Brown et al., 2004) describes that allometric relationship of exponent for 3/4 applies only to the great individuals of plants. For small individuals of plants, it may be isometric relationship between metabolic rate and body mass, namely exponent is 1. These uncertain relationships may be related to the special process of seed germination progress and seedling growth. For example, the accumulation of metabolic inert organization; metabolic rate changing with the degree of activity of metabolic active parts. At present, there are few reports on this research, especially for the relationship between the characteristic attributes in the progress of seed germination and seedling growth.Based on the above reasons, this paper choose the germinal seeds and seedlings as the research objects, the allometric relationships between the key enzyme activity of respiration and body mass /respiratory rate /moisture content in the process of seed germination are studied by experiment. The experimental results show that: 1) PFK activity of the key enzyme of EMP approach increases continually with cultivating time; IDH activity of the key enzyme of TCA approach rises early and then decreases, presenting a inverted "V" shape trend with cultivating time; MDH activity of the key enzyme of TCA approach rises early and then decreases; G6 PDH activity of the key enzyme of PPP approach rises early and then decreases, and increasing rapidly to reach the peak in a short period of time, then decreases gradually. This trend may be related to the various roles of different metabolic approaches in the progress of seed germination and seedling growth. 2) The allometric between the activity of PFK/MDH/IDH/G6 PDH and body mass are 1.377/1.478/1.150/1.116. Overall, the relationship between the four enzymes and body mass is isometric and the exponents are slightly bigger than 1. 3) The allometric exponents between the activity of PFK/ IDH/ MDH/ G6 PDH and body mass are 0.898/1.085/0.832/1.112, all experimental values are close to 1. This is similar to isometric relationship between metabolic rate and body mass of small plants proposed by Metabolic Theory of Ecology(MTE); 4) The allometric exponent between the activity of PFK/IDH and individual moisture content are 0.557/ 0.562; the allometric exponent between the activity of MDH/ G6 PDH and individual moisture content are 1.041/-0.991. The allometric exponents between the latter two enzymes and body mass is close to 1, which is approximate to isometric relationship.To analyze the causes of the above results, we consider it may be associated with the complexity and diversity of plant respiration metabolism during seed germination and seedling growth progress. So we can’t use a single model to explain the growth process because different respiration pathways are activated to varying degrees. The role of different respiration pathways are also quite different. In addition different respiration pathways are not entirely independent. But from the research results of our experiment, we could make generalizations of general changing rules of various respiration pathways in the progress of seed germination and seedling growth. In the transformation period from breaking dormancy to seed germination and the early stage of seeds germination. PPP respiration pathway plays a significant role; during the whole process from seed germination to seedling, the activation degree of EMP respiration pathway continuously push forward and become more and more significant in the later; TCA respiration pathway follows the EMP respiration pathway, the activation degree increased gradually in the early and decline gradually in the later. The results of this study has certain reference value for the study of the allometric relationships between different characteristic attributes of plants’ small individuals, and laid a solid foundation for further study.