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甘蔗(Saccharum L.)是重要的糖料作物,典型的C4植物。选育抗旱甘蔗品种是当前生产上一个重要任务。本文选择抗旱性不同的7个甘蔗品种,进行桶栽实验,从叶片解剖结构、光合特性和耐旱性方面探讨它们的水碳协调关系。结果表明:(1)叶片厚度、表皮厚度、叶肉细胞厚度表现为强抗旱>中等抗旱>弱抗旱品种;(2)抗旱性强的品种叶脉密度显著高于抗旱性较弱的品种,气孔密度、叶脉密度和净光合速率(P_n)正相关;(3)强抗旱性品种的叶片具有较高的维管束鞘面积比率(BS:M),这种BS:M与Pn、水分利用效率正相关,与叶片膨压丧失点负相关;(4)叶片耐失水能力与P_n正相关。综上可知,抗旱性强的甘蔗品种更具碳水代谢优势,它们的高BS:M既提高了叶片供水能力,又提高了叶片CO_2浓缩能力,进而有利于获得高光合速率;同时,甘蔗的耐旱性与光合能力保持协调。研究结果对甘蔗抗旱栽培和育种具有参考意义,也为解释C_4草本植物高光合效率提供了新证据。
Sugarcane (Saccharum L.) is an important sugar crop, a typical C4 plant. Breeding drought-resistant sugarcane varieties is an important task in current production. In this paper, seven varieties of sugarcane with different drought resistance were selected for barrel experiment to discuss their water-carbon coordination relationship from the anatomical structure, photosynthetic characteristics and drought tolerance of leaves. The results showed that: (1) Leaf thickness, epidermis thickness and mesophyll cell thickness showed strong drought resistance> moderate drought resistance> weak drought resistance varieties; (2) Leaf resistance of drought-resistant cultivars was significantly higher than that of weaker drought resistance stomatal density, Leaf density and net photosynthetic rate (P_n) were positively correlated. (3) The leaves of the highly drought-tolerant cultivars had higher vascular bundling sheath area ratio (BS: M). This BS: M was positively correlated with Pn and water use efficiency, And negatively correlated with the loss of leaf turgor pressure; (4) Leaf resistance to water loss was positively correlated with P_n. In summary, the drought-resistant sugarcane varieties have more carbohydrate metabolism, their high BS: M both increased leaf water supply capacity, but also increased leaf CO2 enrichment capacity, and thus conducive to obtain high photosynthetic rate; the same time, sugar cane resistance Drought and photosynthetic ability to maintain coordination. The research results have reference significance for the drought-resistant cultivation and breeding of sugarcane, and also provided new evidence for explaining the photosynthetic efficiency of C_4 herbaceous plants.