野生鸭儿芹种子休眠特性及破除方法

鸭儿芹种子具有休眠特性,且休眠期长,不经任何处理的种子很难萌发,影响其人工种植。研究了鸭儿芹种子的休眠特性和解除休眠的最佳方法,为我国人工种植野生鸭儿芹提供理论依据。结果表明:TTC法对种子活力的测定表明有活力的种子为(55.33±3.71)%;切破种皮种子与完整种子吸水率在前12 h相差较大,但最终吸水率相差不大,分别达到(70.00±1)%和(68.32±0.32)%,表明种皮并不阻碍种子吸水;种子中存在内源抑制物,其粗提液在较低浓度下即可抑制芹菜种子的萌发;鸭儿芹种子成熟时胚未分化完全,胚率为(28.65±2.488)%,经过低温处理后完成后熟,胚率达到(65.93±3.86)%,萌发率达到100%,因此鸭儿芹种子具有形态生理休眠特性。清水浸种和低温冷藏共同处理可有效解除其休眠,浸种和低温冷藏具有交互效应,浸种36 h、5℃冷藏30d即可解除其休眠,萌发率达到100%,发芽势达到(91.11±0.91)%。已破除休眠的种子适宜其萌发的温度范围扩大(15.0—27.5℃),而且在土壤中也可较好地萌发,萌发率达到(96.67±3.33)%,发芽势达到(71.11±1.93)%。

Dormancy break approaches and property of dormant seeds of wild Cryptotaenia japonica

Cryptotaenia japonica Hassk.(Umbelliferae),a perennial herbaceous plant,is native to China and Japan.It usually favors humid eco-environment.This plant species is both an edible and pharmaceutical plant.C.japonica is a popular vegetable in Japan and usually served as salad or prepared in soup.But in China it is usually cooked and then served.This plant can be cultivated year round in green houses.And due to easy handling,C.japonica is also grown hydroponically.Its nutritious and pharmaceutical nature are of great concerns among agriculturalists and farmers.The aromatic ingredient in the whole plant also has commercial and industrial potential.To the best of my knowledge,only a few studies have been addressed to C.japonica as yet.And these studies have been concentrating on the nutrient and mineral elements,its potential as dietary food,the volatile constituent,the pharmaceutical purposes and toxicology,and its morphological anatomy.No studies however according to my knowledge have ever tried to investigate its ontogenesis like seed germination and seed dormancy.Our studies will lend support to the artificial cultivation of C.japonica.C.japonica seeds are characterized by a long dormancy period and will not germinate without any treatment,thereby impeding its agricultural cultivation.The objectives of the present research were to investigate the reasons for seed dormancy and optimal approaches to dormancy break of C.japonica seed and to supply theoretical fundamentals for its artificial cultivation.The results showed that,based on TTC(triphenyltetrazolium chloride) staining method,only(55.33±3.71)% of the seeds were viable,but the germination rate was close to zero.Although the imbibition rates of broken and intact seeds differ markedly in the early 12 hours,the final imbibition rates were almost the same,i.e.(70.00±1)% and(68.32±0.32)%,respectively,suggesting that seed imbibition is not impeded by seed coat.When celery seeds were treated with the crude extracts of C.japonica seeds for about 24 hours,the seed germination of celery was inhibited.A possible reason is that there are endogenous inhibitants in the low-concentration crude extracts of C.japonica.The embryo of matural C.japonica seed was not developed completely since the percentage of the length of embryo/length of endosperm was only(28.65±2.488)%.After post maturation under low temperature it was close to(65.93±3.86)% and the germination rate was almost 100%.C.japonica seed therefore was featured by morphophysiological dormancy.Both soaking with tap water and storage under low temperature can break effectively the dormancy of C.japonica seeds and both methods interact with each other.Similarly,with increasing soaking and storage time,seed germination rate and germination potential also increased gradually.In particular,soaking with tap water for 36 hours and storage at 5 ℃ for 30 days can break seed dormancy and the germination rate and germination potential can be close to 100% and(91.11±0.91)%,respectively.The optimal temperature for the germination of dormancy-broken seeds was 15.0—27.5 ℃ and better germination rate and germination potential in soil can be(96.67±3.33)% and(71.11±1.93)%,respectively.