Bouton J H, Brown R H, Evans P T, Jernstedt J A
Department of Agronomy, University of Georgia, Athens, Georgia 30602.
Plant Physiol. 1986 Feb;80(2):487-92. doi: 10.1104/pp.80.2.487.
Species in the Laxa group of Panicum have C(3) or C(3)/C(4) photosynthesis based on leaf anatomical and CO(2) exchange characteristics. Hybrids were previously made between C(3)/C(4) and C(3) species in this group (RH Brown et al. 1985 Plant Physiol 77: 653-658). In this paper, CO(2) exchange, morphological, and leaf anatomical characteristics of F(2) or F(5) progeny from colchicine-induced amphiploids of C(3)/C(4) x C(3) hybrids (Panicum milioides Nees ex Trin. [C(3)/C(4)] x Panicum laxum Mez [C(3)] and Panicum spathellosum Doell [C(3)/C(4)] x Panicum boliviense Hack. [C(3)]) were studied.There were no differences found in morphology or physiology between the amphiploids and the F(1) hybrids from which they were produced. In the segregating progeny, CO(2) compensation concentration and photorespiration values typical of C(3), but not of C(3)/C(4) plants, were recovered. Progeny were found from both crosses which possessed O(2) inhibition of apparent photosynthesis typical of the parents, and in the case of the P. milioides x P. laxum cross, leaf anatomy and overall plant morphology typical of the parents were observed in some progeny. The progeny were found to possess recombinations of various traits associated with reduced photorespiration, so that no correlation existed among O(2) inhibition of apparent photosynthesis, CO(2) compensation concentration, and leaf anatomical traits. One plant was especially noteworthy in possessing leaf anatomy typical of C(3)/C(4) plants, but with CO(2) exchange characteristics of C(3) plants.
根据叶片解剖结构和二氧化碳交换特征，黍属Laxa组中的物种具有C(3)或C(3)/C(4)光合作用类型。此前已在该组的C(3)/C(4)和C(3)物种之间培育出了杂种（RH Brown等人，1985年，《植物生理学》77: 653 - 658）。在本文中，对秋水仙碱诱导的C(3)/C(4)×C(3)杂种（黍稷[C(3)/C(4)]×黍稷[C(3)]和黍稷[C(3)/C(4)]×黍稷[C(3)]）的F(2)或F(5)后代的二氧化碳交换、形态学和叶片解剖特征进行了研究。在这些双二倍体与其产生的F(1)杂种之间，未发现形态学或生理学上的差异。在分离后代中，恢复了典型C(3)植物而非C(3)/C(4)植物的二氧化碳补偿浓度和光呼吸值。在两个杂交组合的后代中都发现了具有亲本典型的表观光合作用氧气抑制现象的植株，在黍稷×黍稷杂交组合中，在一些后代中观察到了具有亲本典型的叶片解剖结构和整体植株形态。发现这些后代具有与降低光呼吸相关的各种性状的重组，因此表观光合作用的氧气抑制、二氧化碳补偿浓度和叶片解剖性状之间不存在相关性。有一株植物特别值得注意，它具有典型C(3)/C(4)植物的叶片解剖结构，但具有C(3)植物的二氧化碳交换特征。
