甜荞果皮开裂类型及其对籽粒早期萌发性状的影响

Cracking types of common buckwheat pericarp and its effect on early germination traits

关键词:  甜荞, 籽粒, 果皮开裂, 萌发特性

Key words:  common buckwheat, grain, husk cracking, germination traits

摘要:

甜荞是我国传统的药食同源植物,籽粒是甜荞的重要贮藏器官,籽粒果皮的开裂类型及其开裂行为影响种子的萌发性状。该研究以5份甜荞为材料,进行果皮裂口的建模与分型,并通过纸床发芽法,检测种子的发芽率、胚根及下胚轴长度。结果表明:(1)甜荞籽粒果皮开裂主要包括纵向完全开裂型、种孔端部半开裂型、种脊中部半开裂型、种脐端部半开裂型和横裂型等5种类型;(2)开裂型籽粒比完整型萌发时间提早约12 h;(3)开裂型籽粒早期萌发率均高于相应的果皮完整型,但48 h后,完整型籽粒的萌发率超过果皮开裂型;(4)开裂型籽粒胚根及下胚轴的早期增长速度比完整型快,但果皮开裂型籽粒胚根与下胚轴增长比值显著小于果皮完整型;(5)不同开裂类型的萌发率从大到小依次为种孔端部半开裂型、纵向完全开裂型、种脐端部半开裂型、种脊中部半开裂型、横裂型,而种子霉烂率从大到小依次为种脐端部半开裂型、纵向完全开裂型、种脊中部半开裂型、种孔端部半开裂型、横裂型。果皮开裂虽然可以提高甜荞种子早期的萌发率,促进胚根及下胚轴早期的伸长速度,但会降低甜荞整体的萌发率以及胚根/下胚轴增长比值,种子霉烂率显著增加,不利于田间壮苗与全苗的形成。

Abstract:

Common buckwheat, a traditional edible and medical plant, which grain is an important storage organ. However, types of husk-cracking of commom buckwheat and it's germination effects is a scientific and technological problem to be solved. In the present study, five samples of common buckwheat were used as materials. The grain model of common buckwheat was established and the types of pericarp cracking were classified; at the same time, through the paper bed germination method, testing the seed germination rate, the radicle and hypocotyl length. The results were as follows:(1)There are five kinds of cracking types in the grain of common buckwheat, which are longitudinal complete dehiscence type(LCD), semi-dehiscent micropyle(SDM), semi-dehiscent mid-ridge(SDMR), semi-dehiscent hilum(SDH)and transverse cracking type(TC);(2)Five test common buckwheat pericarp cracked type germinates about 12 hours earlier than the pericarp intact type;(3)The early germination rate of common buckwheat varieties with pericarp cracking was higher than that of the corresponding pericarp intact type, however, 48 h later, the germination rate of seeds with intact pericarp continued to increase, and exceeded that of all pericarp cracked types;(4)On the extension characteristics of radicle and hypocotyl, although the growth rate of radicle and hypocotyl of pericarp cracking type were faster than that of intact type of pericarp, the ratio of radicle to hypocotyl of intact pericarp type was higher than that of pericarp cracking type;(5)Different type of pericarp cracking had different effects on seed germination, from big to small, which is SDM, SDH, LCD, SDMR and TC, respectively. Different type of pericarp cracking had different mildew rate, from big to small, which is SDH, LCD, SDMR, SDM and TC. There are five common cracking types in common buckwheat grain pericarp; although pericarp cracking can improve the early germination rate of common buckwheat seeds and promote the early extension rate of radicle and hypocotyl, it can reduce the germination rate and the ratio of radicle to hypocotyl growth of common buckwheat as a whole, it may not be conducive to the formation of strong seedlings and whole seedlings in the field.