Effects of Exogenous Putrescine Application on Hormone Content of Citrus aurantium L. Seedling under Salt Stress

A pot experiment was conducted in lath house to study the response of six month-old seedlings of sour orange （Citrus aurantium L.） irrigated with salinity water （1, 2 or 4 ds/m） for four month. The seedling was sprayed with putrescine at 0, 150 or 300 mg/L concentrations for three times with month interval, for investigation the effects of putrrescine spraying on hormonal changes in sour orange seedlings under salt stress. One month after the last putrescine application, the leaves of the vegetative shoots were picked for endogenous plant hormone determination. The results indicate that increasing level of irrigation water salinity to 4 ds/m significantly increased ABA, Put and SA; whereas, decreasing IAA and GA in leave. Spraying vegetative canopy with putreseine at 300 mg/L increased 1AA, SA, ABA and Put, while decreased GA. It can be concluded that the adverse effects of high salinity irrigated water on endogenous plant hormone can be ameliorated, to some extent, by exogenous application of Put at 150 mg/L or 300 mg/L concentration.

Selection of Tolerant of Some Citrus Hybrids F1 to Calcareous Stress and Identification Sexuall Individuals by SSR Marker

The research was conducted during two seasons 2018-2019 and 2019-2020, at the Scientific Research Center in Lattakia-Syria, where the cross between Sour orange, Cleopatra mandarin and Trifoliate orange. The first season was (Sour orange ♂ × Cleopatra mandarin ♀) and (Cleopatra mandarin ♂ × sour orange ♀) and (sour orange ♂ × trifoliate orange ♀), and the crossing in the second season was (Trifoliate orange ♂ × Sour orange ♀), and (Trifoliate orange ♂ × Cleopatra mandarin ♀). The plants of the first generation F1 were exposed to calcareous stress according to two methods. The first one for a long term (two years) method was grown in plots containing 15% and 35% Calcium Carbonate and the control free of Calcium Carbonate for the first cross, and the second one short term (two months) by watering method was with a solution of 1 mol and 2 mol of Calcium Carbonate for the second cross. The indicators of proline and chlorophyll A, B and T were measured in the first-generation individuals, once at the beginning of the experiment and a second time at the end of study. Seven SSR primers were used to identify sexual individuals, five primers were able to identify sexual F1 individuals are CSM13, CSM17, CSM147, CSM18 and TAA27, F1 individuals in the first season (mixture experiment) gave high values of chlorophyll and were tolerant to calcareous stress from crossing Cleopatra mandarin and Sour orange, where they did not show a deterioration in chlorophyll, but rather increased chlorophyll values, and the Trifoliate orange hybrids were sensitive to this stress, and in the watering experiment the F1 showed significant deterioration in Chlorophyll in all seedlings, and symptoms of Lime-induced chlorosis appeared on the more sensitive seedlings.