Study On The Characteristics Of Growth And Development Of Jacaranda Mimosifolia

With the change of the external environmental conditions, the perennial woody plants showed a series of physiological and morphological changes, and presented some growth development regular pattern. With the change of climate, the plant showed different physiological and morphological changes in the life course, known as growth cycle. Understanding and mastering the plant growth cycle was one of the core content of the plant arrangement and landscape expression. To this end, for some unstudied fields on growth and development characteristics of plants was particularly important, such as Jacaranda mimosifolia.This study took the adult tree of Jacaranda mimosifolia grown in Neijiang and Chengdu of Sichuan Province as test material. Through two years entire observation in2010to2011and a combination of biology and other related theories, the paper discussed the basic law of growth and development and its related factors of Jacaranda mimosifolia. In order to provide theoretical and technical basis for plant landscape and nursery stock production of Jacaranda mimosifolia. The following conclusions can be drawn through the experimental study:1. The growth phenophase of Jacaranda mimosifoliaGermination period was March to early April, Leaf-expansion period was April to late May, Florescence I was early April to late July, Florescence Ⅱ was August to September, Fructescence was July to mid-November, and Deciduous Dormant period was early December to next February or early March. When month average temperatures up to10～15℃between March and April, Jacaranda mimosifolia began to break dormancy and into infancy, and then after50～70d leaf exhibition, sprouting and other vegetative growth process, finally entered the reproductive growth stage. The Florescence I was in late April to early July, and Florescence II was in mid-August until the end of September. The squid appeared green flat ovoid fruit in early July, and the fruit would successively litter after the weather got warmer in the following year. In early December to next February or early March, the leaves began to gradually disappearing, and went into the period of dormancy. This was the full-year growth and development of Jacaranda mimosifolia.2. The growth and development characteristics of Jacaranda mimosifoliaAccording the survey in Neijiang and Chengdu Wenjiang found that Jacaranda mimosifolia sprouted shoots three times a year, namely spring shoot in April to June, summer shoot from July to late August and autumn shoot at late August to late September. The adult trees in Neijiang pumped annual shoots at the average length of31.9cm. Among them, the spring shoots was14.2cm, summer shoot was at average length of10.6cm, autumn shoot was7.1cm. But in Wenjiang, the annual shoots was29.6cm, the spring shoots was13.2cm, summer shoot was at average length of10.3cm, autumn shoot was6.1cm. There was no difference in the annual shoots length, the spring and summer shoots accounted78%of the shoot length, autumn shoot represented22%of annual growth. In the horizontal branches was associated with a small amount of leggy branches, and the leggy branch was at average length of180cm around, equivalent to six times of the vegetative shoots. Throughout the whole year of sprouting process, it also appeared twice florescence phenology, namely florescence Ⅰ in late spring&early summer (May to June) and florescence Ⅱ in autumn (August to September). The flowering branch was at average length of25cm, and they were mainly birthed on the current nutrition branches, but a little amount of part was birthed on the biennial branches, and had alternate flowering habit. But from the point of flower mass of florescence Ⅰ and Ⅱ, the former was four times that of the latter. It could be seen that the annual growth of Jacaranda mimosifolia was large, its vegetative growth was mainly concentrated in spring and summer, Florescence was from spring continually to autumn, and performed all better in the spring and summer.3. The relationship between growth&development and temperature&humidity Meanwhile, according to the relationship between biological growth&development and environment, the growth&development of Jacaranda mimosifolia and its ecological factors existed following relations:its growth biological zero is between8℃to10℃.When the month average temperature in11～13℃above, relative humidity among75%, emerged vegetative growth, and the effective accumulated temperature was in370～440℃. When the month average temperature between15℃to20℃, relative humidity at80%, appeared reproductive growth., and the effective accumulated temperature was in2300～2600℃.Therefore, it existed intrinsic link between growth&development of Jacaranda mimosifolia and environmental conditions. This provided a certain theoretical basis and technological support for on cultivation, configuration and landscaping of garden plant.4. Floral organs structure of Jacaranda mimosifoliaThe survey found that the inflorescence of Jacaranda mimosifolia was panicle and perfect flower. Corolla edge was2lipped,4stamens,2long2short or4long. Another stamen was degraded, top filamentous crack, middle covered dense white fluff, and fit grew with style.1single pistil, no faceplate, ovary oblong and superior, two-compartment, each compartment was1-2crack with majority ovule, upper half was sparsely puberulent. Style20～21mm long, Stigma not significant and slightly flattened in nearly triangular.However, some issues remain to be studied further. For instance, during the whole growth and development process of Jacaranda mimosifolia, the intrinsic link with light and soil, and the growth correlation between aboveground and belowground.