Lignin is a phenolic biopolymer that limits the intake potential and energy availability of forage crops. In order to understand the lignification process, enzymatic and biochemical studies were conducted at four different growth stages of tall fescue (Festuca arundinacea Schreb.). An increase in phenylalanine ammonia lyase and tyrosine ammonia lyase activity was observed with advancement of growth from first node palpable stage to third node palpable stage with a decrease at spikelet emergence stage. Cinnamoyl-CoA reductase and peroxidase exhibited a continuous significant (p < .05) increase and positive correlation with lignin concentration. Cinnamyl alcohol dehydrogenase exhibited a significant (p < .05) positive correlation with lignin concentration, suggesting its probable exclusive role in tall fescue lignification. Cellulose and total phenol exhibited a 13.0 and 71.8% increase, whereas pectin and crude protein exhibited a significant (p < .05, p = .0001) decrease of 65.1 and 15.4%, respectively, with the growth advancement from first node palpable to spikelet emergence stage. Klason lignin also exhibited a dramatic 9.4-fold increase from vegetative to reproductive stage. The enzymatic and biochemical alterations were closely associated with the lignification process. This study provides an integrated picture of the enzymatic and biochemical alterations that accompany changes in lignin deposition in tall fescue.

中文翻译：

---

高羊茅不同生长阶段木质素沉积的酶生化变化

木质素是一种酚类生物聚合物，可限制饲料作物的摄入潜力和能量可用性。为了了解木质化过程，在高羊茅 ( Festuca arundinacea Schreb.) 的四个不同生长阶段进行了酶促和生化研究。观察到苯丙氨酸解氨酶和酪氨酸解氨酶活性随着生长从第一节可触及阶段到第三节可触及阶段的进展而增加，而在小穗出现阶段则下降。肉桂酰辅酶 A 还原酶和过氧化物酶表现出持续显着 ( p  < .05) 增加并与木质素浓度呈正相关。肉桂醇脱氢酶表现出显着（p < .05) 与木质素浓度呈正相关，表明它可能在高羊茅木质化中起唯一作用。纤维素和总酚表现出 13.0% 和 71.8% 的增加，而果胶和粗蛋白表现出显着的 ( p  < .05, p  = .0001) 下降，分别为 65.1% 和 15.4%，从第一节可触及到小穗的生长进展萌芽阶段。从营养阶段到生殖阶段，Klason 木质素也表现出惊人的 9.4 倍增加。酶促和生化改变与木质化过程密切相关。这项研究提供了伴随高羊茅中木质素沉积变化的酶促和生化变化的综合图景。