Proposition 13 has turned sour for some Southern California lemon growers, but it has helped to sweeten the guacamole for the state's avocado producers.

These are among the freakier immediate effects of the Jarvis-Gann Property Tax Limitation Initiative, which became law yesterday. As the new 1 percent of market value property tax limit became official, the consequences included:

People who live in cities where voters have approved bond issues will find themselves with a tax bill higher than the 1 percent rate. The initiative contains an escape clause, allowing this additional tax, which will boost taxes on the average, statewide, 10 to 15 percent higher than Jarvis-Gann supposedly allows. In some communities the actual bill will be 50 percent higher than the supposed legal limit.

Some renters will find significant decreases in their rents as Howard Jarvis promised when he was campaigning for Proposition 13, while others will face increases. One large Northern California landlord, L. B. Nelson of Menlo Park, has announced rent reductions averaging $30 a month beginning Aug. 1. But two renters' organizations in Southern California said they had received many complaints about rent increases, despite the new tax break.

Business leaders, including many who opposed the initiative, continue to forecast new prosperity because of Proposition 13. The state Chamber of Commerce says that a poll of its members shows that business plans to invest $2.9 billion in expansion in the next year and create 2.400 new jobs. The state's businesses received an estimated $3.5 billion tax break under the measure.

Many homeowners will receive a double break from Proposition 13, at least in the short run. In addition to lower taxes, surveys by real estate companies indicate a strong surge in the housing market, as lower taxes bring more buyers into the field. Southern California's long housing boom had begun to flatten in recent months, partly because of the high property taxes.

What has become apparent in the 3 1/2 weeks since Proposition 13 was approved is that the measure is likely to have very uneven impacts.

A case in point is the contrary example of the lemon growers and the avocado growers. A shortage of lemon acreage in 1975, the base year for property tax assessment under Jarvis-Gann, and a strong demand for lemons in Japan sent values up to $7,000 an acre.

Since then, overplanting of lemon groves, bumper crops and a reduced demand abroad have caused the value of lemon groves to plummet to a few hundred dollars an acre. But unless the groves have changed hands, they will have to be assessed at the 1975 market value.

The situation is the reverse for avocado growers.

Assessments on avocado land in Ventura County more than doubled in 1976 and 1977, up to $5,500 an acre, because of increased demand for guacamole in the East and Midwest. Avocado growers, whose land is still increasing in value, will be assesed at the $2,500-per-acre values of 1975.

Such variations will be commonplace in California because the inflation here and the property taxes that reflect this inflation have not been uniform in growth.

The situation was further complicated Thursday by the State Board of Equalization, which reversed an earlier ruling and ordered county assessors to update all their 1975-1976 assessments.

The Jarvis-Gann Initiative required the 1975-1976 roll be used for assessment purposes, but ignored the fact that some properties had not been reassessed since 1969. The board's decision instructs assessors to update all properties to what they would have been if reassessed in 1975, a decision that will add an estimated $320 million in property tax revenues for local governments.

In the atmosphere of uncertainty prevailing in California, two of state's largest banks, Crocker National and Wells Fargo, have taken full-page ads in the state's major newspapers to pledge reinvestment of their proposition 13 tax windfalls.

Many of the state's banks and almost all of the savings and loan companies have reduced monthly payments for homeowners, reflecting the tax decrease. Crocker and Wells Fargo claimed in their ads that this would mean more money for consumers and stimulation for the economy.

Privately, some big businessmen acknowledge that they are worried about the long-term potential of a proposal by labor unions and teachers' groups to create a tax rall that would limit the benefits of Proposition 13 to privately owned residences. It is almost certain that such an initiative will not be on this November's ballot, but businesses fear it will become a real alternative in future years, when the decrease in government revenues triggers a corresponding decrease in services.

Whatever else Proposition 13 does, it already has added to a boom in legal business as governments, businesses and individuals take to the courts in an effort to resolve the many questions posed by the initiative.

Though Howard Jarvis and other Proposition 13 supporters were fond of saying that their initiative was in plain language anyone could understand, it is already apparent that the language of the measure has raised more questions than it has answered. In the early hours of its existence. Proposition 13 has proved to be the lawyers's friend.