Amphicarpy And Ecological Adaptation Of Ceratocarpus Arenarius L. In Xinjiang

The reproductive characteristics of amphicarpy of monoecious Ceratocarpus arenarius L. were elementarily studied in the Junggar Desert, including phenology, floral morphology and space place, fruit types and morphology, fruit space place, fruit growth and development characteristics, fruit distribution pattern, seed germination characteristics, and reproductive allocation. The results of research as follow:1)Life history of C. arenarius is eight month. The reproductive growth phase was much longer than the vegetative growth phase that was only one month. C. arenarius goes in reproductive growth phase with nutritious growth phase after pure nutritious growth phase.2)The flowering sustainability is a characteristic of C. arenarius. Generally,the female flowers are axillary and solitary; the staminate flowers are acrogenic. When it is flowering, the female flowers and the staminate flowers crowdedly arrange in cephalanthium. It is believed that the female and staminate flower spatial arrangement provides the better space place for the female flower pollination.3)C. arenarius has amphicarpy in which a plant produces aerial as well as subterranean fruits. The subterranean fruits originate from two female flowers in the binate axils of the first node of principal axis. At the last ten-day of April, the two female flowers are pollinated on the ground; after bracts entirely concrete, the two subterranean fruits develop into underground in the middle ten days of June. And other females develop aerial fruits. Two types of fruits are different in colour, size, shape, weight, number and distribution. It is found that the number of green aerial fruits is greatly more than the orange subterranean fruits, which are only two.4)The differences of aerial and subterranean seeds result in seed heteroplasmy, and seed heteroplasmy brings on different germination behavior between aerial and subterranean seeds. After 30-days of incubation at different alternating temperature 5/15℃, 5/25℃, 15/25℃in 12 h dark / 12 h light photoperiod, the subterranean and aerial seeds of C. arenarius have different germination percentage and germination rate. The cold stratification can enhance germination percentage and germination rate of the aerial and subterranean seeds, so this indicates that the aerial and subterranean seeds have physiological seed dormancy. The scarification on the seed coat can hasten and increase germination percentage and germination index of the aerial and subterranean seeds in three different alternating temperature. The prolonging storage period can also result in increasing of germination percentage and germination rate of aerial seeds, and partly of the subterranean seeds, and this shows that aerial seed dormancy is lighter than subterranean seeds'.5)In its life history, reproductive allocation of C. arenarius changes all the whole. Reproductive allocation (RA) of reproductive organs is increasing over 50% with time going, while RA of nutritious organs is decreasing. The aerial reproductive organs are in reproductive dormancy period between July and August, and they grow again in September. RA of aerial reproductive organs apparently changes from 0% to 57.8%, and RA of subterranean reproductive organs relatively keeps stabilized. Subterranean fruits mature earlier than aerial fruits from reproductive time.The results show that amphicarpy of C. arenarius is an especial reproductive strategy for adapting to variable environment on desert.