Waterlogging Tolerant Indicators and Water Physiology of Chrysanthemum
Date Issued
2012
Date
2012
Author(s)
Chiu, Yi-Hsuan
Abstract
Chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitam.] is majorly cultivated in the field in Taiwan. Heavy rain may result in waterlogging, which affects plant growth and yield. It is vital to determine growth and physiological responses to flooding of chrysanthemum cultivars and to establish the criteria for the breeding or selection of waterlogging tolerant chrysanthemum cultivars. The results in chapter 3 experiment 1 showed that 3 days short-term waterlogging caused growth reduction of 21 chrysanthemum cultivars. Root and shoot weights, plant heights, leaf sizes, and leaf number were reduced, together with chlorosis in recently fully developed leaves on 14 days after the waterlogging treatment. Among the chrysanthemum cultivars tested, ‘F15’ and ‘Remix’ grew well either after a 3-day waterlogging or a 10-day hypoxia.
Three-day waterlogging followed by 7-day recovery in chapter 4 experiment 1 showed that stomatal conductance and net photosynthesis reduced more in ‘Hua-Yu-Dieng’ and ‘Regatta’ than in ‘F15’ and ‘Remix’. After 1-day drainage, stomatal conductance and photosynthesis recovered in ‘F15’ and ‘Remix’. The concomitant increase in intercellular space CO2 concentration and the decrease in stomatal conductance and net photosynthesis after drainage of ‘Hua-Yu-Dieng’ and ‘Regatta’ suggested that waterlogging not only reduced stomatal conductance but also caused carboxylation limitation. No significant decrease in the maximal quantum yield of photosystem II photochemistry (Fv/Fm) after waterlogging in the four tested cultivars. The waterlogging-intolerant ‘Regatta’ grafted on tolerant ‘F15’ rootstock resulted in increased photosynthesis after waterlogging, suggesting that waterlogging tolerance is closely related to root performance.
Three-day waterlogging followed by 6-day recovery in chapter 5 showed that H2O2 and MDA concentrations remained unchanged in ‘F15’ and ‘Remix’, but increased in ‘Hua-Yu-Dieng’ and ‘Regatta’. H2O2 and MDA concentrations in leaves could be reliable makers for evaluating the waterlogging tolerance of chrysanthemum cultivars. The activities of SOD, CAT, APX, and GR were unaffected after waterlogging in ‘Hua-Yu-Dieng’. ‘Regatta’ had higher but appeared insufficient of SOD, CAT, and GR activities after waterlogging, because H2O2 and MDA concentrations still increased.
Linear relationships were found between measurements of WET and SM100, and with gravimetric method, indicating that using WET Sensor (WET) and WaterScout SM100 (SM100) soil moisture sensors to measure volumetric water contents (VWC) would facilate irrigation management. Plants had the highest net photosynthesis rate when grown at 50% VWC as measured with WET. Drought reduced photosynthesis rate earlier than the leaf water potential, suggesting that measurement of photosynthesis was more sensitive than that of leaf water potential. Before visible floral bud stage, chrysanthemum grew well at 30% VWC as measured with SM100. Waterlogging-intolerant cultivars wilted when grown with higher VWC (50% measured with SM100). Lower VWC (below 20% measured with SM100) resulted in reduced plants growth and inflorescence diameter. Stomata conductance and growth were reduced more in ‘Regatta’ than in ‘F15’, ‘Remix’, and ‘Hua-Yu-Dieng’.
Deficit irrigation (14%-22% VWC) after visible floral bud stage did not alter time to anthesis, although plants had smaller inflorescences diameter and shorter main peduncle length at harvest. Well irrigated (40%-55% VWC) plants exhibited increases in inflorescence diameter and number of opened inflorescence during vase life. Plants grown under deficit irrigation after visible floral bud stage had cut flowers with lower stomatal conductance and transpiration rate, which led to better water balance and delayed water loss. However, different irrigation treatments after visible floral bud stage did not affect the vase life of the cultivars tested.
In waterlogging-intolerant cultivars, stomatal conductance and net photosynthesis reduced during waterlogging together with accumulation of H2O2 and MDA in leaves. After drainage, intolerant cultivars exhibited stomatal closure and carboxylation limitation. In contrast, waterlogging-tolerant cultivars showed recovery of stomatal conductance and photosynthesis after drainage. The waterlogging-intolerant cultivars did not grow well when grown under 50% VWC, as measured with SM100. Plant grew faster under well irrigated (30% VWC measured with SM100) before visible floral bud stage than those under 20% VWC. Reduced irrigation to 14%-22% VWC as measured with SM100 after visible floral bud stage resulted in cut flowers with delayed water loss.
Subjects
Dendranthema
flooding
photosynthesis
antioxidative enzyme
soil water content
preharvest water stress
water balance
Type
thesis
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