Ignat Solzhenitsyn finds his repertoire close to the heart. His programs with the Chamber Orchestra of Philadelphia trace to some deeply personal event or connection. In the ensemble's concert Sunday at the Perelman Theater, he led the premiere of Vladimir Martynov's

De Profundis

, a work dedicated to his late father. But, in leading two of Mendelssohn's teenage symphonies, he was returning to his own student discoveries of these extraordinary pieces. These programs are a kind of self-portraiture.

The Muscovite Martynov, 62, wrote his work for the ensemble as a tribute to Alexander Solzhenitsyn. It evokes the solemn procession of chanting monks, a four-note motif in basses and violas moving through gradual changes as other strings join. The mood remains hushed and dark, leavened by a soaring viola interlude, played by principal Alexandra Leem, then joined by Ellen Trainer and Philip Kramp. The work gradually moves higher, with a dull throb of timpani, and ends with the ensemble searching a high, tense note, the last cry of anguish. The work's economy is in the tradition of Barber's

Adagio for Strings

and many of the Eastern European composers who work in dark shades, gradual evolutions, and long-held notes.

That somber note contrasted starkly with the other works on the program. Carl Nielsen's

Flute Concerto

splashes instrumental color, and challenges the flute to find its place with joyous outbursts, suave lyrical moments, and spicy orchestral textures. Edward Schultz, the orchestra's principal, proved adept at finding the piece's mood, textural shifts and expansive nature.

The concerto is ripe with novelty. The flutist finds himself paired with bass trombone in one place, and in another discovers his playing stretched over throbbing timpani. The cadenza was shared with other strings. Schultz's command of the work let its individuality emerge as incisive musical thinking, giving it the feeling of superb achievement.

Solzhenitsyn has lived with the teenage Mendelssohn almost since his own teens, having appeared at piano lessons at Curtis to play one symphony or another for then-director Gary Graffman's approval. Sunday, he opened with

Symphony No. 3

and

Symphony No. 8

, giving the orchestra wings in sharing his admiration for the precocious music. The latter, with winds and brass, caught the best of their efforts - here were color, transparency and wit. Imagine the 13-year-old writing that slow movement; imagine the restraint of the child in shaping the quick movements. Solzhenitsyn let his audience imagine all that.