GLOBAL MARKETS-Relief for Europe as Scotland stays in United Kingdom

* Sterling runs out of puff after jump on Scotland result * World stocks head for fifth week of gains in six * Nikkei surges after yen bumps to 6-year low vs dollar * Alibaba prices IPO at top of range, bolstering sentiment * Wall Street's S&P 500 expected to open 0.3-0.4 pct higher By Marc Jones LONDON, Sept 19 (Reuters) - World markets rallied on Friday as Scotland's decision to stay in the United Kingdom lifted Europe and got investors over the latest in a recent run of tricky global political hurdles.

Scotland voted to remain in the UK by 55 percent to 45 percent, a clear outcome likely to bring relief to a number of countries in Europe, particularly Spain, which is facing similar secessionist pressures in Catalonia.

Sterling initially surged to a two-week high against the dollar and a two-year peak against the euro before losing some steam, while London's FTSE share index and Spanish stocks and bonds jumped.

Global shares were already heading towards their fifth weekly gain in the last six. They have been boosted by further assurances this week that interest rates are likely to remain at record lows in many major economies for some time.

News that Chinese internet giant Alibaba priced its IPO at $68 a share on Thursday, the top end of the expected range to raise $21.8 billion in one of the world's largest-ever stock offerings, also supported the market.

"I am happy today, risk is back on, everybody is happy today," said Geir Lode, head of global equities for fund manager Hermes in London. "We have Scotland, Alibaba is huge - what could be better?" Scotland's vote against independence ended a fraught two weeks for markets that had seen the value of sterling fall sharply after some polls suggested the 307-year old union was on the brink of collapse.

The vote not only keeps Britain intact but also reduces the likelihood of its leaving the European Union, potentially a much greater risk for markets and something Scottish independence might well have precipitated, analysts said.

The pound's bounce against the dollar was not as large as some had predicted though and it had retreated to $1.6386 as U.S. trading began.

But it remained strong against some of the other major currencies, hitting a two-year high of 78.10 pence per euro and a six-year high of 180.70 yen.

YEN FLOOR, NIKKEI ROAR The cheer from the still-United Kingdom spread to the rest of Europe's bourses, and Wall Street was also expected to start on the front foot after another week of record highs.

The euro zone's blue-chip Euro STOXX 50 index rose 0.7 percent before traders took profits in London and Frankfurt and nerves started to show in France ahead of a sovereign rating review by Moody's.

Spain's IBEX outperformed with a 0.7 percent rise, helped by a fall in Spanish 10-year government bond yields as markets viewed Scotland's "No" vote as having reduced prospects of a stronger push for a breakaway in Catalonia.

"For the markets in general, the Scottish result is probably the best outcome because the 'Yes' vote winning was really not priced in and that could have caused chaos, with contagion to Europe," said Clairinvest fund manager Ion-Marc Valahu.

Asia shares outside Japan had added 0.2 percent, supported by Wall Street's strong showing overnight after Alibaba's IPO bonanza, though the region was still on track for a weekly loss of about 1.4 percent.

Japan's Nikkei ended up 1.6 percent at a seven-year closing high, giving it a 2.3 percent gain for the week. Shares got a tailwind as the yen hit a new six-year low of 109.46 yen to the dollar and as Prime Minister Shinzo Abe said he aimed to reform the country's $1.2 trillion public fund as soon as possible.

ECB FRUSTRATION The dollar index, which tracks the currency against a basket of six peers, stood at 84.547, edging up on the day after it climbed as high as 84.743 on Thursday, its strongest level in more than four years.

There was further frustration for the ECB on Friday. Its favoured inflation gauge, the five-year/five-year forward , hit a new low and banks handed back 20 billion euros just a day after taking a disappointing 83 billion euros in the first of its much-hyped TLTRO loan offerings.

The euro shed about 0.5 percent to $1.2858 after hitting a 14-month low on Thursday, when it fell as low as $1.2834.

Risk sentiment seemed unruffled by geopolitical clouds on the horizon. The U.S. Senate on Thursday approved a bill requested by President Barack Obama to arm and train moderate Syrian rebels fighting Islamic State militants, while tensions continued to rumble between Ukraine and Russia.

Among commodities, Brent crude held below $98 a barrel, but was set for its first weekly gain in three on the possibility of lower OPEC output. Brent edged down to $97.63 a barrel, while U.S. crude slipped slightly to $92.94.

Traditional safe-haven gold inched lower to $1,224.40 an ounce after touching $1,216.01 in the previous session, its lowest since Jan. 2. Copper was also limping toward a fourth straight week in the red, hurt by concerns over slowing economic growth in top consumer China.

(Additional reporting by Anirban Nag in London; Editing by John Stonestreet and Hugh Lawson)