(1) Flowering and fruiting characteristics Plants propagated by seeds bloom in the spring of the second year, with a flowering rate of about 30%; plants propagated by rhizomes bloom in May of the same year, with a flowering rate of 73%; the flowering period of two years old and above is slightly earlier.
From the bud to the first flower open about 11 to 25 days, the flowering period of the early and late flowering period is related to the temperature of the flowering period; flowering time, to the beginning of the flower 2-8 days after the flowering of the most, accounting for 89.08% of the total number of blooms, a day in the morning to 7-9 a.m. most of the blooms, accounting for about 80% of the total number of blooms above.
Generally, the flowering period is from May to August, and the fruiting period is from August to October, but the flowering period is very long, and there are still flowers in September.
(2) Seed Embryo Development The growth and development of the fruit from the expansion of the ovary to the complete development of the embryo requires three major stages, namely, the expansion of the fruit (9 to 12 days), the seed growth period and the development of the embryo (more than 40 days). The rate of progress of each growth period depends on the temperature and humidity conditions at the time, the fruit borne by the May bloom, the completion of the above three stages takes about 60 to 70 days; July bloomers, the completion of the entire reproductive process takes about 50 days, and after September bloomers, the seed embryo is too late to develop the temperature drops and stops growing. It is observed that between the seeds of the same fruit sequence, the size of the embryo also exists a significant difference, due to the different size of the embryo body of each seed, the time required to complete the embryo after ripening is also significantly different. The largest embryo, to reach the embryo length at germination (2.4 mm), at a suitable temperature of 27 ℃, it takes 15 days, the embryo grows about 1 times during this period; the smallest embryo, to reach the embryo of the seed germination, it takes more than 30 to 40 days. Embryo in this period of growth 2.0 to 2.5 times, such as low temperature, this process is significantly delayed.
Seed weight of 9.62 grams per thousand grains, the general germination rate of only 40% to 60%, due to the seed maturity is not the same, resulting in the germination of the seed is very untidy, the germination rate is also low. The use of low-temperature sand storage treatment can greatly improve the germination rate, low temperature (5 ℃ or so) sand storage treatment 30 ~ 40 days better. If the seed by low temperature sand storage treatment (1 ~ 3 ℃ 30 days) after sowing can make the seed germination 9 ~ 10 days earlier, germination rate of 88% ~ 91%. Production should be harvested in August before the flowering of the seed sowing.
Seed germination temperature of 20 ~ 30 ℃, there is enough humidity, about 25 ~ 28 days seedling, such as lower than 10 ℃ or higher than 30 ℃, the germination is inhibited.
(3) rhizome growth characteristics The root growth of Dioscorea bulbifera starts from mid-March and ends in mid-October, about 200 days, with rapid growth from August to September, in which asexual reproduction, the growth rate of the current year is 167.4%, and 90% in the second year; sexual reproduction of the growth rate is much slower than that of the asexual reproduction. The content of Diosgenin, whether sexual or asexual reproduction and different age rhizomes, there is no significant difference.
The distribution of the root system of Dioscorea perforata in the soil: mainly concentrated in the upper layer of the soil, asexual reproduction of one or two years of vertical distribution of the root system, the amplitude of about 10-40 cm, horizontal distribution of the amplitude of the radius of 21.5-66 cm; sexual reproduction of the root system of the vertical distribution of asexual reproduction is basically the same as the amplitude of the horizontal distribution of the radius of 21.5-38 cm.
The formation of Diosgenin, according to seedling observation, found that after sowing the seedling, the growth of about 20 days, rhizomes began to appear, Diosgenin has also been formed, to the late seedling, the content can reach 1.14%. At the same time, it was found that light plays a good role in the growth of rhizomes and the accumulation of saponin elements in the late seedling stage.
(4) Requirements for environmental conditions The temperature conditions of Penstemon are widely adapted to, and the temperature during the growth period in Beijing is from 8 to 35℃, and the suitable temperature for growth is from 15 to 25℃. In the early stage of plant growth, it requires slightly lower temperature, about 8~20℃. High temperatures during flowering and fruiting have the effect of early flowering and accelerated fruit growth. Observed temperature at 15 ~ 20 ℃, the same inflorescence from the pregnant bud to the first floret opening takes 25 days, while the temperature increases to 20 ~ 28 ℃, the time of flowering can be shortened to 11 ~ 14 days. Dormant period is suitable for lower temperatures, high temperatures are not conducive to the dormancy of the rhizome and the growth of the following spring.
Because the root system is more developed, so there is a strong drought tolerance, but the seedling stage of drought tolerance is poor, in the spring drought area, especially the year of asexual reproduction, the root system is not yet fully developed, the need for appropriate irrigation, in order to ensure that the seedling survival and normal growth. In the later stages of plant growth, watering should not be too much, otherwise it will be too high soil moisture, and cause root rot and death.
Light has an adverse effect on seedling emergence and the early stage of seedlings, strong light will often cause the leaves to dry and die. And the late seedling and adult plants, light on the accumulation of Dioscorea saponin element has a certain role in promoting.
The requirements for soil conditions are not strict, and sandy loam soil with medium fertility is the best. Soil pH to weak acid to weak alkaline is more suitable. Because it is more drought-resistant, it is especially suitable for planting in hillside land, hills or ditches.