Seasonal Variation Of Reed Photosynthetie Pigments Of Different Leaf Age Class From Heterogeneous Habitats In Songnen Plain

Leaf is the only place where the photosynthesis process occurs and is the productionworkshop of plants. Most of leaf’s inner tissue differentiated into parenchyma rich inchlorophyll and made the leaves looks green. Photosynthesis is the process that plants usessolar energy to transform water and carbon dioxide into organic matter which stored chemicalenergy and release oxygen. Both chlorophyll a and chlorophyll b are unstable and are easy todecomposition whenever the climate such us light intensity and light quality changed. Theplasticity and variation of form, structure, physiological and biochemical characteristics,content and proportion of organic and inorganic components of leaf are quiet important forplants’ adapting. The plasticity and variation of pigments in reed (Phragmites communis)leaves from4heterogeneous habitats, that is, seasonal watered habitat (H1), Leymuschinensis-Phragmites communis mixed habitat (H2), alkali spot habitat (H3) and sandyhabitat at artificial forest edge (H4), respectively, in Songnen Plains of China were analyzedquantitatively, and the following results are reached:(1) Pigments of reed leaves sampled from heterogeneous habitats showed significantplasticity. The average contents of chlorophyll a and chlorophyll b are significantly higher inH4rather than other habitats, while the average content of carotenoids is higher in H3thanany other habitats during the growing season. The different variations of different pigmentsare useful adaptation to various environments for reed.(2) The decrease of chlorophyll content was the main reason leads leaf brown andsenescence. The highest chlorophyll content in July is2.0~3.3times of that in September,while the carotenoids content increase only1.6~1.9times compared to the bottom co ntent,and the carotenoids content even decrease a little in September in H4.(3) The seasonal variation of chlorophyll content and carotenoids content followingdifferent laws. The former one following parabolas with a downward opening, while the latterone following a parabolas with a upward opening, and both reached their extremum duringthe late July and early August.(4) The pigments contents of reed from heterogeneous habitats followed the sameregularity to adapt the climate. The average contents of chlorophyll a and chlorophyll b ofreed leaves from every habitat we tested reached their peak around the last ten days of July,while carotenoids the valley value. From the local climate data we known that the average temperature and the average precipitation for every ten days during1953and2011reachedtheir peak at the last ten days of July,23.82℃and49.91mm, respectively. It means that thereeds from any heterogeneous habits in Songnen Plain have already adapted the local climateindependent of niches.