Identification of Photosynthesis Characteristics and Chlorophyll Metabolism in Leaves of Citrus Cultivar (Harumi) with Varying Degrees of Chlorosis

Abstract

In autumn and spring, citrus leaves with a Ponkan (Citrus reticulata Blanco cv. Ponkan) genetic background (Harumi, Daya, etc.) are prone to abnormal physiological chlorosis. The effects of different degrees of chlorosis (normal, mild, moderate and severe) on photosynthesis and the chlorophyll metabolism of leaves of Citrus cultivar (Harumi) were studied via field experiment. Compared with severe chlorotic leaves, the results showed that chlorosis could break leaf metabolism balance, including reduced chlorophyll content, photosynthetic parameters, antioxidant enzyme activity and enzyme activity related to chlorophyll synthesis, increased catalase and decreased enzyme activity. In addition, the content of chlorophyll synthesis precursors showed an overall downward trend expected for uroporphyrinogen III. Furthermore, the relative expression of genes for chlorophyll synthesis (HEMA1, HEME2, HEMG1 and CHLH) was down-regulated to some extent and chlorophyll degradation (CAO, CLH, PPH, PAO and SGR) showed the opposite trend with increased chlorosis. Changes in degradation were more significant. In general, the chlorosis of Harumi leaves might be related to the blocked transformation of uroporphyrinogen III (Urogen III) to coproporphyrinogen III (Coprogen III), the weakening of antioxidant enzyme system activity, the weakening of chlorophyll synthesis and the enhancement in degradation.

Enhancing Growth and Biochemical Traits of Helianthus annuus L. Under Drought Stress Using a Super Absorbent Dextrin–Polyacrylamide Hydrogel as a Soil Conditioner

“…Additionally, decreased chlorophyll content may be associated with decreased photosynthetic enzymes . In contrast, the results from phase II, where the hydrogel was employed in drought conditions, showed increased chlorophyll concentration compared to the control phase I.…”

“…Additionally, decreased chlorophyll content may be associated with decreased photosynthetic enzymes. 40 In contrast, the results from phase II, where the hydrogel was employed in drought conditions, showed increased chlorophyll concentration compared to the control phase I. This indicates that the hydrogel application can help mitigate the negative impact of drought on the chlorophyll content of sunflower plants.…”

Leaf Traits Explain the Growth Variation and Nitrogen Response of Eucalyptus urophylla × Eucalyptus grandis and Dalbergia odorifera in Mixed Culture

“…On the other hand, interspecific relationships based on complementary effects are largely influenced by N availability [84]. Yao et al reported that leguminous plants transfer N to eucalyptus trees through root contact, as shown by the 15 N isotope labeling method [35,54]. This phenomenon has been observed in mixed plant species such as wheat and faba bean [85], maize and soybean [86], and Acacia mangium and Eucalyptus [55].…”

“…Leaf tissue density (LTD) and leaf dry matter content Plants 2024, 13, 988 2 of 21 (LDMC) are used to estimate the compactness level and extent of leaf tissue growth, which may be related to plant responses to soil nutrient resources [6,12]. Regarding output, the net photosynthetic rate (Pn) is a decisive indicator of photosynthetic efficiency in leaves and is influenced by stomatal conductance (gs), transpiration rate (Tr), and intercellular carbon dioxide concentration (Ci) [13,14], while chlorophyll content (Chl) determines the flux size of photons received in leaves [15]. In addition, Rubisco carboxylation efficiency (CE) reflects the carboxylation efficiency of the key rate-limiting enzyme of photosynthesis [16], and leaf water-use efficiency (WUE) reflects the water use by the leaves and is closely related to the photosynthetic process [17].…”

Genome-Wide Association Study to Identify Possible Candidate Genes of Snap Bean Leaf and Pod Color

“…Phvul.004G031900 and Phvul.004G032000 (at 3,910,100-3,975,292 bp) were associated with chlorosis and variation in maturity caused by a deletion in stop codon [60] and they were a candidate for C* pod interior and exterior in G19833 (the equivalent being Pv5-593.04G036100 in 5-593) (Table S1). In chlorotic tissues, as photosynthesis and the amount of chlorophyll decreases, the decrease in chlorophyll accelerates, and a color change occurs in the tissues by affecting various pigment syntheses [61].…”