Dominant Gene cplsr1 Corresponding to Premature Leaf Senescence Resistance in Cotton (Gossypium hirsutum L.) A Comparative Study on Photosynthetic Characteristics and Photoprotective Mechanisms between Torreya grandis cv. ‘Merrilli’ and Torreya grandis Direct Primary Somatic Embryogenesis and Shoot Formation from Immature Leaves of Manihot esculenta Research on the photoprotection and photosynthesis characteristics of young cotton leaves under field conditions