《植物生理学报》 2017, 53(4): 705-712

七个甘蔗品种叶片解剖结构特征与光合能力和耐旱性的关联

秦茜^1,2, 朱俊杰^1,2, 关心怡^1,2, 于天卉^1,2, 曹坤芳^1,2,*

¹广西大学林学院, 广西森林生态与保育重点实验室培育基地, 南宁530004; ²亚热带农业生物资源保护与利用国家重点实验室, 南宁530004

通信作者：曹坤芳；E-mail: kunfangcao@gxu.edu.cn

摘　要：

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P_n、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CO₂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C₄草本植物高光合效率提供了新证据。

关键词：甘蔗; 抗旱性; 叶片解剖; 光合特征; 膨压丧失点; 水分关系

收稿：2017-02-20   修定：2017-03-17

资助：国家自然科学基金(31460102)和广西自然科学基金(2015-GXNSFAA139082)。

The correlations of leaf anatomical characteristics with photosynthetic capacity and drought tolerance in seven sugarcane cultivars

QIN Xi^1,2, ZHU Jun-Jie^1,2, GUAN Xin-Yi^1,2, YU Tian-Hui^1,2, CAO Kun-Fang^1,2,*

¹Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China; ²State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Nanning 530004, China

Corresponding author: CAO Kun-Fang; E-mail: kunfangcao@gxu.edu.cn

Abstract:

Sugarcane (Saccharum L.) is an important sugar-production crop and a typical C4 plant. Presently, an important task in agriculture in subtropical and tropical regions is to breed drought-tolerant sugarcane cultivars. In this paper, we investigated the coordination between water supply and carbon assimilation in sugarcane cultivars with different drought tolerance. Seven sugarcane cultivars were chosen and cultivated in barrels with sufficient water and nutrient supplies. We measured leaf anatomy and hydraulic structure, leaf turgor loss point, as an indicator of drought tolerance, and gas exchange properties from these cultivated plants. The results show that, (1) the leaf thickness, epidermis thickness and mesophyll thickness decreased gradually from high, medium to low drought-tolerant one. (2) Vein density was significantly higher in high drought-tolerant cultivars than in low-tolerant cultivars. Stomatal density and vein density were positively related to net photosynthetic rate. (3) The leaves of high drought tolerance cultivars had higher ratio of bundle sheath area to mesophyll area on cross section basis. This ratio was also correlated positively with net photosynthetic rate, water use efficiency and negatively with the leaf turgor loss point. (4) The capacity of leaf resistance to desiccation was positively related to net photosynthetic rate, which contradicts the conventional knowledge of the trade-off between plant productivity and stress resistance. In conclusion, the sugarcane cultivars with high drought tolerance have particular water and carbon assimilation advantages. The drought tolerance and photosynthetic capacity were coordinated in sugarcane cultivars. The findings of the present study would have important implications for the breeding of drought-tolerant sugarcane cultivars and provide new evidence to explain high photosynthetic efficiency in C₄ grasses.

Key words: sugarcane; drought resistance; leaf anatomy; photosynthetic characteristics; turgor loss point; water relation