Studies On Albinism Of Crassula Arborescens

Crassula arborescens belongs to Crassulaceae Crassula.The leaves fleshy,strong-storage-capacity,drought,strong-cold-resistant. By hypothermia induced Crassula arborescens blades produced different color but unique Crassula arborescens albino leaf,and a red leaf edge around circle, which not only brings a unique visual sense,also adds color to the landscape. By analyzing the albino leaf Rubisco and chlorophyll biosynthesis enzyme activity to determine the expression of two-way signaling and coordinated response system feedback mechanism between chloroplast genome and the nuclear genome, and further provide a theoretical basis for the mechanism of Crassula arborescens albino leaves.The experiment using microplate reader analyzed Rubisco activity changes in the process of greenable albino Crassula arborescens,in which was induced through hypothermia produce albino blade,then through the change of Rubisco activity to determine the Crassula arborescens albino leaves carbon sequestration capacity, viability and practical value;By the change of key chlorophyll synthesis activity to evaluated the ability of chlorophyll synthesis;To evaluate the activities of life through soluble protein content changes in albino leaves;By light and electron microscopy to compare the differences in the microscopic and submicroscopic structure, namely through organizational structure,cell structure and ultrastructure to determine the differences of the hypothermia induced in Crassula arborescens albino leaf with normal leaf structure,further infer its metabolism. Using microplate reader analysis results show that the activity change, low-temperature-induced albino Crassula arborescens Rubisco initial activity(156.23pg/ml) when compared to fully recover leafy piece (323.43pg/ml) is low,less than half the normal leaves,but the ability of photosynthesis still exist,producing organic synthesis. Showing that albino Crassula arborescens still could carry on photosynthesis,still have the ability to survive, have ornamental value; Changes in the way of soluble protein is consistent with Rubisco, shows that at low-temperature-induced,albino Crassula arborescens chloroplast ribosomes translation process is unusual; hypothermia induced albino Crassula arborescens in the process of greenable,Crassula arborescens all white leaves Rubisco activity and soluble protein content gradually increased. With the increase of leaf pigment content, the chloroplast photosynthesis gradually increased, photosynthetic products gradually accumulated,thus contributing to increased life energy plant substances soluble protein in vivo.Chlorophyll biosynthetic enzyme glutamyl-tRNA reductase(GluTR) and Mg2+-chelating enzymes and protochlorophyllid oxidoreductase(POR) activity showed a negative correlation.At low-temperature-induced, starting Crassula arborescens albino plants GluTR activity is relatively high,so that makes intermediate ALA accumulation,resulting in chlorophyll biosynthesis intermediates significantly reduced at subsequent stages, which matches with Mg2+-chelating activity and the POR activity lower at initial stage.Thus speculated:chlorophyll biosynthesis may be blocked in the glutamyl-tRNA to protoporphyrin IX biosynthesis stage.Through the change of Rubisco activity to determine the Crassula arborescens albino leaves carbon sequestration capacity, viability and practical value and by the change of key chlorophyll synthesis activity to evaluated the ability of chlorophyll synthesis,Which could provide a theoretical basis for the study of low-temperature-induced albino Crassula arborescens leaf.According to light and electron microscopy to observe the greenable Crassula arborescens and the low-temperature-induced albino Crassula arborescens,the light microscopy observations showed that:Crassula arborescens leaf epidermal cells of stomata was anisocytic type, epidermal cells is flat, mesophyll tissue cells without palisade and spongy tissue differentiation.The structure of stomata was anisocytic type at hypothermia induced albino Crassula arborescens,which is similar to the normal Crassula arborescens,but mostly closed, and the bottom of the epidermal cells have many idioblast,which were stained dark brown; the normal Crassula arborescens epidermis stomata mostly open.In order to avoid excessive moisture loss and ensure the normal photosynthesis,stomatal closure in albino Crassula arborescens.Transmission electron microscopy observations shows that the number of hypothermia induced albino Crassula arborescens mesophyll chloroplasts is small, more elongated oval or spherical,the structure is relatively loose, grana lamellae sparse. In a non-all-white period, appeared in many cystic vesicles,in which focus on the chloroplast membrane edge,then these cystic vesicles forming the electron density sparse vacuoles,and near the site of vacuolar the chloroplast lamination stack is blur,grana thylakoid structure suffered varying degrees of damage, suggesting that the chloroplast is constantly degraded;Until all white era,some chloroplast completely disintegrated almost mitochondria completely degraded or disappeared, remaining cell walls form a grid-like profile, there is no structural integrity of chloroplast and mitochondrial structure, almost no other cellular structures,indicating that the cells at this time has been completely degraded.However,the greenable Crassula arborescens chloroplast grana lamellae clearly evident, mitochondria clear.Scanning electron microscopy results showed that:normal Crassula arborescens leaf starch granules,lipid droplets and aleurone were more intensive than the hypothermia induced Crassula arborescens, indicating its strong chloroplast photosynthesis; There is no significant difference between the two of vascular structures, but in the low-temperature-induced Crassula arborescens saw many storage protein crystalline or amorphous solid structure,which were more than the greenable Crassula arborescens.Through organizational structure,cell structure and ultrastructure to determine the differences of the hypothermia induced in Crassula arborescens albino leaf with normal leaf structure, further infer its metabolism.