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蓝花丹开花生物学观测及花粉储存研究

Flowering biological characteristics and pollen preservation of Plumbago auriculata

  • 摘要: 对四川引种栽培的蓝花丹(Plumbago auriculata Lam.)花粉与柱头形态、花部特征及开花物候进行了系统观测,并对其花粉的采集时间与储存温度进行了初步研究。结果显示:(1)两种类型花粉和柱头形态均具有较大差异,短花柱型(S型)花粉的极轴长P值和赤道轴长E值均显著大于长花柱型(L型)花粉,L型柱头则明显长于S型,且两种花粉的纹饰和柱头的瘤状突起物形态也明显不同;(2)蓝花丹具有较高的开花同步性指数(为0.89),但相对开花强度不高,属于中等强度;(3)蓝花丹两种花型在花蕾半开放时采收花粉,其活力最高,L型花粉活力可达85.24%±4.22%,S型可达87.74%±2.95%;(4)L型与S型花粉分别于25℃干燥0.5 h和1 h后再低温储存,其活力保持更好;(5)干燥后的花粉在-86℃条件下保存效果最好,储存30 d后L型花粉活力高达66.51%±0.85%、S型达69.07%±1.57%。本研究表明蓝花丹二型植株在生殖资源分配上存在明显差异,这种差异一方面导致花粉大小和形态及其所需干燥时间的不同,另一方面导致二型花柱头表现出明显不同的特征,这些差异性的结构是否参与了蓝花丹自交不亲和反应的识别过程,还有待进一步研究。此外,较低的开花强度会造成虫媒传粉困难,这可能是蓝花丹自然结实率极低的重要因素之一。

     

    Abstract: Pollen and stigma morphologies, floral characteristics, and flowering phenologies of introduced and cultivated Plumbago auriculata Lam. in Sichuan were systematically observed, with the collection period and storage temperature of pollen also examined. Results showed:(1) There were obvious differences between pollen and stigma morphology; P (polar axis length) and E (equatorial axis length) values of S-morph pollen were significantly higher than that of L-morph pollen; the stigma of the L-morph pollen was significantly longer than that of the S-morph pollen; and the exine ornamentation and stigma stromae of the two morphs of pollen were significantly different. (2) P. auriculata had a high flowering synchrony index of 0.89, but its relative flowering intensity was at a mid-level. (3) When the two morphs of pollen were harvested during the half-flowering period, viability reached the highest levels. The L-morph pollen viability reached 85.24% ±4.22% and S-morph pollen viability reached 87.74% ±2.95%. (4) L-morph and S-morph pollen maintained better viability when stored at low temperatures after drying at a constant temperature of 25℃ for 0.5 h and 1 h, respectively. (5) Dried pollen was best stored at -86℃, and after 30 d of storage the L-morph pollen viability was 66.51% ±0.85% and S-morph pollen viability was 69.07% ±1.57%. In summary, there were significant differences in the reproductive resource allocation between the two morph plants of P. auriculata, with differences in the size, morphology, and drying time of pollen, and significantly different characteristics in the stigma. Whether these different structures participate in the self-incompatibility reaction of P. auriculata remains to be further studied. In addition, low flowering intensity can cause insect pollination difficulties, which may be an important factor in the extremely low natural seed setting rate.

     

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