Trade-offs For Leaf Nitrogen Allocation To Photosynthetic Machinery And Insecticidal Protein Or Genetic Material

Invasion plants cause serious costs on the ecological environment, social economy and human health in the invaded ranges. Studies on mechanisms for the successness of the invasive plants is one of the key aspects of the invasion biology. Unravelling these mechanisms is also valuable for predicting and controlling invasive plant. Hypothesis of the evolution of nitrogen allocation is a new theory in plant invasion, which proposes that the successness of exotic plants in invasive ranges could be explained by partitioning nitrogen, originally allocated to plant defense, to photosynthetic organs as the escape of natural enemies of the exotic plants in invasive ranges. As it has been proposed recently, more experiments are needed for further validation of this hypothesis. In this study, we used three plant species, an insect-resistant cotton, an insect-resistant rice and an autotetraploid strawberry. We aimed to examine trade-off relationships between leaf nitrogen allocated to photosynthetic machinery and insecticidal protein or genetic material, and how the tradeoffs varied under low, intermediate and high nitrogen addition treatments. The insect-resistant transgenic plants synthesize insect-resistant protein, which enhance their defense capability during the growth. Autopolyploid strawberries with more genetic material might entail more nitrogen compared with than diploid strawberries. According to the hypothesis of the evolution of increased nitrogen allocation, the increased allocation to defense or genetical materials may affect the leaf nitrogen allocation to photosynthetic apparatus, and hence influence the photosynthetic capacity and efficiency of photosynthetic nitrogen use efficientcy as well as plant morphology and biomass allocation of plant, etc.There is a negative correlation between leaf anti-insect protein nitrogen content and photosynthetic apparatus nitrogen in the insect-resistant cotton under low and middle nitrogen treatments, while no such correlation was found under all the three nitrogen treatments for the insect-resistant rice. There’s a significantly negative correlation of autopolyploid between the genetic material nitrogen and photosynthetic apparatus nitrogen under the high nitrogen addition treatment (r=-0.754; P=0.012), wheras no such correlation appeared for the autotetraploid Fragaria pentaphylla L. of red-fruited under each of the three N addition treatments.The results showed that in transgenic insect-resistant plants the trade-offs between nitrogen in photosynthetic apparatus and nitrogen in anti-insect proteins were affected by levels of these protein expression, soil nitrogen availability and individual plant life history traits. For autotetraploid strawberries, the trade-offs between the photosynthetic apparatus nitrogen and genetic material nitrogen were influenced by levels of soil nitrogen and life history traits.