Karun A, Sjini K K, Niral V, Amarnth C H, Remya P, Rajesh M K, Samsudeen K, Jerard B A, Engelmann F
Central Plantation Crops Research Institute, Kasaragod, Kerala, India.
Central Plantation Crops Research Institute, Kasaragod, Kerala,India.
Cryo Letters. 2014 Sep-Oct;35(5):407-17.
Coconut genetic resources are threatened by pests and pathogens, natural hazards and human activities. Cryopreservation is the only method allowing the safe and cost-effective long-term conservation of recalcitrant seed species such as coconut.
The objective of this work was to test the effect of cryopreservation and of cryostorage duration on coconut pollen germination and fertility.
Pollen of two coconut varieties (West Coast Tall WWCTW and Chowghat Orange Dwarf CODC) was collected in March-May over three successive years, desiccated to 7.5 % moisture content (FW) and cryopreserved by direct immersion in liquid nitrogen.
Germination and pollen tube length (PTL) of desiccated and cryopreserved pollen were not significantly different for both WCT and COD over the three harvest months of the three consecutive years of study. Pollen germination ranged from 24 to 32 % in desiccated pollen whereas it was between 26 and 29 % in cryopreserved COD pollen. In the case of WCT, germination ranged from 30 to 31 % in desiccated pollen, while it was between 28 and 32 % in cryopreserved pollen. PTL of cryopreserved pollen ranged between 224-390 nm and 226-396 mm for COD and WCT, respectively. Germination of COD pollen varied between 29.0 and 44.1 % after 4 years and 1.0/1.5 years cryostorage, respectively. Germination of WCT pollen did not change significantly between 0 and 6 years cryostorage, being comprised between 32 (24 h) and 40 % (1.5 years). Germination and vigour of cryopreserved pollen were generally higher compared to that of pollen dried in oven and non-cryopreserved. Normal seed set was observed in COD and WCT palms using pollen cryostored for 6 months and 4 years. Cryopreserved pollen of five Tall and five Dwarf accessions displayed 24-31 % and 25-49 % germination, respectively.
These results show that it is now possible to establish pollen cryobanks to contribute to coconut germplasm long-term conservation.
椰子遗传资源受到病虫害、自然灾害和人类活动的威胁。超低温保存是唯一能够安全且经济高效地长期保存像椰子这样顽拗型种子物种的方法。
本研究旨在测试超低温保存及超低温保存时长对椰子花粉萌发和育性的影响。
连续三年在3月至5月采集两个椰子品种（西海岸高种WWCTW和乔格哈特橙矮种CODC）的花粉，干燥至含水量7.5%（鲜重），然后直接浸入液氮进行超低温保存。
在连续三年研究的三个收获月份中，干燥并超低温保存的WCT和COD花粉的萌发率和花粉管长度（PTL）均无显著差异。干燥花粉的萌发率在24%至32%之间，而超低温保存的COD花粉萌发率在26%至29%之间。对于WCT，干燥花粉的萌发率在30%至31%之间，超低温保存花粉的萌发率在28%至32%之间。超低温保存的COD和WCT花粉的PTL分别在224 - 390纳米和226 - 396毫米之间。CODC花粉在超低温保存4年和1.0/1.5年后，萌发率分别在29.0%至44.1%之间变化。WCT花粉在超低温保存0至6年期间萌发率无显著变化，在32%（24小时）至40%（1.5年）之间。与烘干和未超低温保存的花粉相比，超低温保存的花粉的萌发率和活力通常更高。使用超低温保存6个月和4年的花粉，在CODC和WCT植株上观察到了正常的坐果。五个高种和五个矮种种质的超低温保存花粉的萌发率分别为24%至31%和25%至49%。
这些结果表明，现在有可能建立花粉超低温库以助力椰子种质的长期保存。
