Abstract: The initiating effects of Ca²⁺ on pollen germination and its regulative role in pollen tube growth were investigated in Pinus yunnanensis and Nicotiana tabacum. High concentration of Ca²⁺(10^-1 ～10^-2mol/L) in the medium caused severe inhibition of pollen germination and tube growth, but lower concentration of Ca²⁺ or Ca²⁺-deficiency(10^-3 ～ 0 mol/L)had little effect onpollen germination and tube growth. Measurement of Ca content ingerminating pollen showed that there was a significant Ca²⁺ release from pollen during the hydration and early germination phase. However, Ca²⁺ specific chelating agent EGTA led to the inhibition of pollen germination, and this inhibition could be eliminated by re-adding excess Ca²⁺ to the medium containing EGTA. Ca²⁺ channel blockers verapamil and Co₂₊ also caused the inhibition or failure of pollen germination. In addition, Ca²⁺ ionophore A₂₃₁₈₇impeded pollen germination and tube growth. Unlike verapamil and Co₂₊ treatments, pollen tube growth was more sensitive to A₂₃₁₈₇ than pollen germination. These results suggested that Ca²⁺ is indispensible for pollen germination and tube growthalthough exogenous addition of Ca²⁺ to the medium is not necessary. The uptake of Ca²⁺ occurred mainly in early germination phase, and Ca²⁺ could act as an initiator of pollen germination and also as a regulator of pollen tube growth.

Key words: pollen germination, pollen tube growth, Calcium, Ca²⁺ channel blockers, Ca²⁺ ionophore

摘要： 本文以云南松和烟草为材料，研究了钙对花粉萌发和花粉管生长的效应。结果表明花粉萌发介质中高浓度的钙(10^-1～10^-2mol/L)显著抑制了云南松和烟草的花粉萌发和花粉管生长，而较低浓度的钙或缺钙(10^-3～0mol/L)对花粉萌发和花粉管生长无明显影响。测定萌发过程中花粉钙含量变化的结果表明，花粉水合阶段和萌发早期有一急剧的钙释放高峰。在培养介质中加入钙螫合剂EGTA抑制了花粉的萌发，但这种抑制可被随后加入的钙所逆转。钙通道阻塞剂Vera-pamil和Co²⁺也能抑制或阻止花粉萌发，但这种抑制主要发生在花粉萌发的早期。此外，在同浓度的钙载离子体A₂₃₁₈₇的处理下，花粉管生长比花粉萌发过程更为敏感。上述结果暗示着钙可能作为花粉萌发的启动者（Initiator)和花粉管生长的调解者（Regulator）来启动花粉萌发和调节花粉管生长。

关键词: 花粉萌发, 花粉管生长, 钙, 钙通道阻塞剂, 钙载离子体