Blue-helmeted riot police and combat ready soldiers patrolled the streets of Lohore today in the aftermath of Prime Minister Zulfigar Ali Bhutto's lughnting to his rule by arresting its leaders.

Apprehenson was mounting about what may happen Saturday when the leading opposition group, the Pakistan National Alliance, has scheduled a general strike.

It will coinclde with the convening of the newly elected National Assembly in Islamabad. The Alliance is boycotting the session and waging its protest campaign on the ground that the March 7 national elections were rigged by Bhutto's followers.

The key to the success of its campaign lies with the province of Punjab, whose capital is Lahore, contains almost 60 per cent of Pakistan's 74 million people.

AS ONE GOVERNMENT OFFICIAL SAID, "The Punjab still sleeps, but if te glant awakes Bhutto will have to go." No protest movement and no government can hope to survive if the Punjab turns against it.

Islamabad, the national capital, is a new town of government offices and embassies. Karachi, the nation's largest city and the economic capital, is excitable and quick to riot out still a separate entity that can be isolated.

But Labore, with its nearly 3 million people is the political heart of the Punjab and Bhutto himself has called it the most sensitive city in the country.

Bhutto's crackdown on the opposition came before dawn this morning when 24 members of the Pakistan National Alliance were arrested here and in other cities, With the exception of the Alliance's vice chairman, Nawab Zada Nasrullah Khan, virtually all of the Alliance's top leadership are either in jail or under house arrest.

In addition, the president of the Lahore High Court Bar Association, Aammer Raza Knan, along with 83 other presidents of provincial bar associations throughout the Punjab were also placed under detention.

The Punjab's chief minister Sadiq Hussian Qureshi, announced last night that orders have been given to shoot on sight anyone committing arson, looting, damaging private or public property or attempting to disrupt means f communications.

The Punjab may not be fully awake but it is beginning to stir. The alleged election frauds, almost without exception, took place in the Punjab and the fiercely anti-government but sparsely populated provinces of Baluchistan and the Northwest Frontier are watching the Punjob to take their cue.

There was serious trouble reported in the Punjabi city of Multan today out not in Lahore.

Diplomats and knowledgeable Pakistanis say that if Saturday's general strilke is successful in bringing Lahore to a halt, it will be an accurate measure of how long Bhutto can politically survive.

In the meantime one of the few remaining opposition leaders not in jail, Nawab Zaba Nasrullahkhan, gave a press conference today, dressed in a red fez and smoking a water pipe in the rundown offices of the alliance headquarters here. He said the movement to unseat Bhutto would continue even with the opposition leaders in jail "because it is now the people's movement."

Political demonstrations in Lahore follow a certain ritualistic pattern. Today, following afternoon prayers, demonstrators protesting Bhutto's rule forth from seven Mosques throughout the city chanting "there is no Good But Allah and Mohammad is his prophet." They gather in Mosques because the law does not permit free assembly of five or more persons except in the Mosques at prayer time.

In the dung-covered streets and in the narrow alleys outside, riot police awaited them - armed with rifles, tear gas and the dreaded five-foot, steeltipped sticks called "lathis" that the police use to beat the unruly.

Moslem women in black veils hurried by and water buffalos scrambled for a footing in the slippery road.

Suddenly the demonstrators were at the gate, their leaders, garbed in brightly colored cloth, carrying the Koran aloft.

Outside the city gates more police were waiting and the leaders were escorted to a jeep, substituting for a paddy wagon. The protest leaders climbed aboard and were carried off to jail for violating the law prohibiting assembly.

When things go wrong, when the spark is lit, there is a lot of pushing and shoving and there follows the flailing lathis and tear gas. Today the police had a round in the chamber of their rifles. But today the protesters disbanded after their leaders disappeared in custody.

The most impressive of today's processions of protest were the lawyers. At noon about 600 lawyers, dressed in black frock coats and white ties, marched out of the Mogul-style law courts and proceeded down the mall of the new town with the population out and cheering in the streets, in the windows and on roofs along the way.

The lawyers of Lahore have passed a resolution deploring the arrest of their leaders. They have refused to attend court sessions until their leaders are released.

The lawyers of Lahore had intended to march down the mall two by two, so as not to break the law prohibiting assembly, but they were so angry that they all marched together, inviting arrest. Arrest never came, however, and the police simply kept the crowds back.

The populace, although increasingly anti-Bhutto, cheered the police and clapped when the soliders rode by in trucks. Their tactic is to treat the army troops as their downtrodden brothers as well.

The tactic has its ironies. It was Bhutto himself who, 10 years ago, organized the lawyers of Lahore in protest against the dictator of the day, Gen. Ayub Khan. It was Bhutto who encouraged the people to clap when the soldiers or the police arrived to break up protests.