* Shares slide on strengthened bets on early U.S. rate hike
* Too-close-to-call Scotland vote unnerves markets
* Santander's Emilio Botin dies, bank's shares weigh
* Apple euphoria short-lived
By Jamie McGeever
LONDON, Sept 10 (Reuters) - Global shares struggled on Wednesday as markets added to bets on an early U.S. rate hike while nagging concerns over Scotland's future unnerved investors in Europe, hurting sterling and helping the dollar hold on to recent gains.
European stocks flirted with their fourth daily decline in a row and benchmark U.S. Treasury yields rose for the fifth straight session, something not seen since early June.
Shares in the euro zone's biggest bank Santander fell as much as 2 percent, lagging the euro zone and pan-European financials indices , after the sudden death of its 79-year old chairman Emilio Botin.
Earlier, MSCI's broadest index of Asia-Pacific shares outside Japan fell 1.3 percent, its largest fall in nearly six months.
At mid-session the FTSEurofirst index of leading European shares was down 0.1 percent at 1384 points. Germany's DAX was down 0.1 percent, France's CAC 40 was flat and Britain's FTSE 100 up 0.1 percent.
Stock markets' struggles on Wednesday followed broad weakness on Wall Street the previous day after initial excitement over Apple Inc's new products evaporated, and as bond yields continued their march higher.
The 10-year U.S. yield scaled 2.5 percent, lifting European yields, as investors continued to digest a study earlier this week by the San Francisco Fed that showed investors expect slower rate hikes than policymakers themselves expect.
Germany's 10-year yield rose back above 1 percent to 1.02 percent, its highest in a month, and Spain's rose 10 basis points to 2.29 percent.
"The study by the San Francisco Fed unnerved investors that markets are too complacent about the pace of Fed rate hikes," said Nick Stamenkovic, bond strategist at RIA Capital Markets.
"It is only a matter of time before the Fed moves for tighter policy."
The shift towards pricing in an earlier U.S. rate hike helped the dollar hold onto its recent gains.
The dollar hit a six-year high against the yen of 106.79 yen and the dollar index, a basket of its value against six major currencies, hovered near Tuesday's 14-month high.
The euro recovered from Tuesday's 14-month low of $1.2860 back to $1.2943, and sterling hit a 10-month low of $1.6052 before recovering almost a cent.
But with latest official polls suggesting the outcome of the Scottish independence referendum is now too close to call, the "risk premium" surrounding the possibility the 300 year-old United Kingdom could cease to exist next week continues to hang over British financial assets.
The brief sterling dip followed an unverified web poll by an independent blogger that showed the pro-independence camp leading with 53.9 percent.barker.co.uk/scotlandpoll.
Prime Minister David Cameron and the leaders of the other two main political parties travelled to Scotland on Wednesday to try and save the union.
"What you've got is the spectacle of the three main political leaders rushing up to Scotland like a spurned boyfriend trying to placate an aggrieved girlfriend with offers to stay, plucking promises out of thin air," said Michael Hewson, chief strategist at CMC Markets.
On Tuesday, Bank of England governor Mark Carney said Scotland could not be fully independent and have a currency union with the rest of the UK, warning that currency union is "incompatible with sovereignty".
Gold recovered from Tuesday's three-month low of $1,247.15 per ounce to stand at $1,254.10.
For a wrap-up of the news and events driving markets on Wednesday, click on Reuters TV link: reut.rs/1p69LWp